# PART IV -- RIGID BASE COURSES

### **ITEM P-301 SOIL-CEMENT BASE COURSE**

DESCRIPTION

**301-1.1** This item shall consist of constructing a base course by
uniformly mixing together soil, portland cement, and water.  The mixed
material shall be spread, shaped, and compacted in accordance with these
specifications and in conformity to the dimensions and typical cross
section shown on the plans. Tests shall be required for each approved
soil that will be included in the treated layer.

Runway, taxiway, or apron pavements shall be built in a series of
parallel lanes using a plan of processing that reduces longitudinal and
transverse joints to a minimum.

MATERIALS

**301-2.1 PORTLAND CEMENT.**  Portland cement shall conform to the
requirements of ASTM **\[ \]**.

**\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \***

> **The Engineer shall specify ASTM C 150, Type I, II, III, IV, or IV.**

**\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \***

**301‑2.2  WATER.**  Water shall be clean and free from sewage, oil,
acid, strong alkalies, or vegetable matter.  Water of questionable
quality shall be tested in accordance with the requirements of AASHTO T
26. 

**301-2.3 SOIL.**  The soil shall consist of an approved select soil. 
The soil shall be free of roots, sod, weeds, and shall not contain
gravel or stone retained on a 1‑inch (25 mm) sieve or more than 45%
retained on a No. 4 sieve, as determined by ASTM C 136.

**301-2.4 BITUMINOUS MATERIAL.**  The types, grades, controlling
specifications, and application temperatures for the bituminous
materials used for curing the soil‑cement are listed in Table 1.  The
Engineer shall designate the specific material used.

**TABLE 1. BITUMINOUS MATERIALS**

  ---------------------- -------------------- --------------- -------------
  **Type and Grade**     **Specification**    **Application   
                                              Temperature**   

                                              **Deg. F**      **Deg. C**

  Cutback Asphalt                                             

  RC‑70                  ASTM D 2028          120‑160         50‑70

  RC‑250                 ASTM D 2028          160‑200         70‑95

  Emulsified Asphalt                                          

  RS‑1, SS‑1             ASTM D 977           75‑130          25‑55

  CRS‑1                  ASTM D 2397          75‑130          25‑55
  ---------------------- -------------------- --------------- -------------

CEMENT QUANTITY

**301-3.1 LABORATORY SOIL TESTS.**  Prior to base course construction,
laboratory tests of soils shall be made to determine the quantity of
cement required in the mix.

Test specimens containing various amounts of cement are to be compacted
in accordance with ASTM D 558, and the optimum moisture for each amount
of cement is to be determined.  Samples at the optimum moisture shall be
subjected to the wet‑dry and the freeze‑thaw test in accordance with
ASTM D 559 and D 560, respectively.

The specified cement content for construction shall be that at which the
weight loss of the specimens subjected to 12 cycles of either the
wet‑dry or the freeze‑thaw is not more than 14% for granular soils, 10%
for the more plastic granular and silty soils, and 7% for clay soils.

The compressive strength of soaked specimens should increase both with
age and with increase in cement content.

CONSTRUCTION METHODS

**301-4.1 WEATHER LIMITATIONS.**  The soil‑cement base shall not be
mixed or placed while the atmospheric temperature is below 35° F (2° C)
or when conditions indicate that the temperature may fall below 35° F
(2° C) within 24 hours, or when the weather is foggy or rainy, or when
the soil or subgrade is frozen.

**301-4.2 EQUIPMENT.**  The soil‑cement may be constructed with any
equipment that will meet the requirements for soil pulverization, cement
application, mixing, water application, incorporation of materials,
compaction, finishing, and curing specified herein.

**301-4.3 PREPARATION.**  The area to be paved shall be graded and
shaped to conform to the grades and typical cross section shown on the
plans.  Any soft or yielding areas in the subgrade shall be removed and
replaced with acceptable soil and compacted as specified.

**301-4.4 PULVERIZATION.**  The soil for the base course shall be so
pulverized that at the completion of moist‑mixing, 100% by dry weight
passes a 1‑inch (25 mm) sieve and a minimum of 80% passes a No. 4 sieve,
exclusive of gravel or stone retained on the No. 4 sieve.

**301-4.5 CEMENT APPLICATION, MIXING, AND SPREADING.**  Mixing of the
soil, cement, and water shall be accomplished either by the
mixed‑in‑place or the central‑plant‑mixed method.

The percentage of moisture in the soil, at the time of cement
application, shall not exceed the quantity that will permit a uniform
and intimate mixture of soil and cement during mixing operations, and it
shall not exceed the specified optimum moisture content for the
soil‑cement mixture.

**Method A -- Mixed-in-place.**  The specified quantity of cement shall
be spread uniformly on the soil.

Cement that has been displaced shall be replaced before mixing is
started.  After the cement has been applied, it shall be mixed with the
soil.  Mixing shall continue until the cement has been sufficiently
blended with the soil to prevent the formation of cement balls when
water is applied.

Immediately after the soil and cement have been mixed, water shall be
incorporated into the mixture.  Excessive concentrations of water on or
near the surface shall be avoided.  A water supply and pressure
distributing equipment shall be provided that will assure the
application within 3 hours of all mixing water on the section being
processed.  After all mixing water has been applied, mixing shall
continue until a uniform and intimate mixture of soil, cement, and water
has been obtained.

**Method B -- Central plant mixed.**  The soil, cement, and water shall
be mixed in a pugmill, either of the batch or continuous‑flow type.  The
plant shall be equipped with feeding and metering devices that will add
the soil, cement, and water into the mixer in the specified quantities. 
Soil and cement shall be mixed sufficiently to prevent cement balls from
forming when water is added.  Mixing shall continue until a uniform and
intimate mixture of soil, cement, and water is obtained.

The mixture shall be hauled to the project in trucks equipped with
protective covers.  The mixture shall be placed on the moistened
subgrade in a uniform layer by an approved spreader(s).  Not more than
30 minutes shall elapse between the placement of soil‑cement in adjacent
lanes.

The layer of soil‑cement shall be uniform in thickness and surface
contour and of such quantity that the completed base will conform to the
required grade and cross section.  Dumping of the mixture in piles or
windrows upon the subgrade will not be permitted.

Not more than 60 minutes shall elapse between the start of moist mixing
and the start of compaction of soil‑cement.

**301-4.6 COMPACTION.**  Immediately upon completion of the spreading
operations, the mixture shall be thoroughly compacted.  The number,
type, and weight of rollers shall be sufficient to compact the mixture
to the required density.

The field density of the compacted mixture shall be at least 98 percent
of the maximum density of laboratory specimens prepared from samples of
the cement‑treated base material taken from the material in place.  The
specimens shall be compacted and tested in accordance with ASTM D 558. 
The in‑place field density shall be determined in accordance with ASTM D
1556.  Any mixture that has not been compacted shall not be left
undisturbed for more than 30 minutes.  The moisture content of the
mixture at the start of compaction shall not be below nor more than 2
percentage points above the optimum moisture content.  The optimum
moisture content shall be determined in accordance with ASTM D 558 and
shall be less than that amount which will cause the mixture to become
unstable during compaction and finishing.

**301-4.7 FINISHING.**  Finishing operations shall be completed during
daylight hours, and the completed base course shall conform to the
required lines, grades, and cross section.  If necessary, the surface
shall be lightly scarified to eliminate any imprints made by the
compacting or shaping equipment.  The surface shall then be recompacted
to the required density.

**301-4.8 CONSTRUCTION JOINTS.**  At the end of each day\'s run, a
transverse construction joint shall be formed by a header or by cutting
back into the compacted material to form a true vertical face free of
loose material.

The protection provided for construction joints shall permit the
placing, spreading, and compacting of base material without injury to
the work previously laid.  Where it is necessary to operate or turn any
equipment on the completed base course, sufficient protection and cover
shall be provided to prevent damage to the finished surface.  A supply
of mats or wooden planks shall be maintained and used as approved and
directed by the Engineer.

Care shall be exercised to ensure thorough compaction of the base
material immediately adjacent to all construction joints.  When
spreading or compacting base material adjacent to a previously
constructed lane, care shall be taken to prevent injury to the work
already constructed.

**301-4.10 PROTECTION AND CURING.**  After the base course has been
finished to grade and compacted as specified herein, it shall be
protected against drying for a period of 7 days by the application of
bituminous material or other acceptable methods.  The curing method
shall begin as soon as possible, but no later than 24 hours after the
completion of finishing operations.  The finished base course shall be
kept moist continuously until the curing material is placed.

The bituminous material specified shall be uniformly applied to the
surface of the completed base course at the rate of approximately 0.2
gallon  per square yard (0.92 liter/square meter) with approved heating
and distributing equipment.  The exact rate and temperature of
application to give complete coverage without excessive runoff shall be
as specified.

At the time the bituminous material is applied, the surface shall be
dense, free of all loose and extraneous material, and shall contain
sufficient moisture to prevent penetration of the bituminous material. 
Water shall be applied in sufficient quantity to fill the surface voids
immediately before the bituminous curing material is applied.

The curing material shall be maintained and applied as needed by the
Contractor during the 7‑day protection period so that all of the
soil‑cement will be covered effectively during this period.

Finished portions of soil‑cement that are used by equipment in
constructing an adjoining section shall be protected to prevent
equipment from marring or damaging the completed work.

When the air temperature may be expected to reach the freezing point,
sufficient protection from freezing shall be given the soil‑cement for 7
days after its construction and until it has hardened.

Other curing materials such as moist straw or hay may be used if
approved.

**301-4.11 CONSTRUCTION LIMITATIONS.**  When any of the operations after
the application of cement are interrupted for more than 30 minutes or
when the uncompacted soil‑cement mixture is wetted by rain so that the
moisture content is exceeded by a small amount, the decision to
reconstruct the portion affected shall rest with the Engineer.  In the
event the uncompacted, rain‑wetted mixture exceeds the specified
moisture content tolerance, the Contractor shall reconstruct at his/her
expense the portion affected.  All material along the longitudinal or
transverse construction joints not properly compacted shall be removed
and replaced, at the Contractor\'s expense, with properly moistened and
mixed soil‑cement compacted to specified density.

**301-4.12 SURFACE TESTS.**  The finished surface shall not vary more
than 3/8 inch (9 mm) when tested with a 16‑foot (4.8 m) straightedge
applied parallel with, or at right angles to, the longitudinal axis of
the pavement.  Any variations in excess of this tolerance shall be
corrected by the Contractor, at his/her own expense, and in a manner
satisfactory to the Engineer.

**301-4.13 THICKNESS.**  The thickness of the soil‑cement base course
shall be determined from measurements of cores drilled from the finished
base or from thickness measurements at holes drilled in the base at
intervals so that each test shall represent no more than 300 square
yards (250 square meters).  The average thickness of the base
constructed during one day shall be within 1/2 inch (12 mm) of the
thickness shown on the plans, except that the thickness of any one point
may be within 3/4 inch (13 mm) of that shown on the plans.  Where the
average thickness shown by the measurements made in one day\'s
construction is not within the tolerance given, the Engineer shall
evaluate the area and determine if, in his/her opinion, it shall be
reconstructed at the Contractor\'s expense or the deficiency deducted
from the total material in place.

**301-4.14 MAINTENANCE.**  The Contractor shall be required to maintain,
at his/her own expense, the entire base course within the limits of
his/her contract in a condition satisfactory to the Engineer from the
time he starts work until all the work has been completed.  Maintenance
shall include immediate repairs of any defects that may occur either
before or after the cement is applied.  The work shall be done by the
Contractor at his/her own expense and repeated as often as necessary to
keep the area intact at all times.  Repairs shall be made in a manner
that will insure restoration of a uniform surface and the durability of
the part repaired.  Faulty work must be replaced for the full depth of
treatment.  Any low areas shall be remedied by replacing the material
for the full depth of treatment rather than by adding a thin layer of
soil‑cement to the completed work.

METHOD OF MEASUREMENT

**301-5.1**  The quantity of soil‑cement base course to be paid for
shall be the number of square yards (square meters) of completed and
accepted base course.

**301-5.2**  Portland cement shall be measured by the hundredweight.

BASIS OF PAYMENT

**301-6.1**  Payment shall be made at the contract unit price per square
yard (square meter) for soil‑cement base course.  This price shall be
full compensation for furnishing all materials, except portland cement,
and for all preparation, delivering, placing, and mixing of these
materials; and for all labor, equipment, tools and incidentals necessary
to complete the item.

**301-6.2**  Payment shall be made at the contract unit price per
hundredweight for cement. This price shall be full compensation for
furnishing this material and for all delivery, placing, and
incorporation of this material, and for all labor, equipment, tools, and
incidentals necessary to complete the item.

Payment will be made under:

Item P‑301‑6.1 Soil‑Cement Base Course---per square yard (square meter)

Item P‑301‑6.2 Portland Cement---per hundredweight

TEST REQUIREMENTS

ASTM C 136 Sieve Analysis of Fine and Coarse Aggregates

ASTM D 558 Moisture‑Density Relations of Soil‑Cement Mixtures

ASTM D 559 Wetting‑and‑Drying Tests of Compacted Soil‑Cement Mixtures

ASTM D 560 Freezing‑and‑Thawing Tests of Compacted Soil‑Cement Mixtures

ASTM D 1556 Test for Density of Soil In‑Place by the Sand Cone Method

AASHTO T 26 Quality of Water to be Used in Concrete

MATERIAL REQUIREMENTS

ASTM C 150 Portland Cement

ASTM D 977 Emulsified Asphalt

ASTM D 202 Cutback Asphalt

ASTM D 239 Cationic Emulsified Asphalt

**END OF ITEM P-301**

**Intentionally Left Blank**

### **ITEM P-304 CEMENT-TREATED BASE COUSE**

#### DESCRIPTION

**304-1.1** This item shall consist of a cement-treated base (CTB)
course composed of mineral aggregate and cement, uniformly blended and
mixed with water. The mixed material shall be spread and shaped with a
mechanical spreader, and compacted with rollers in accordance with these
specifications and in conformance to the lines, grades, dimensions, and
cross-sections shown on the plans.

#### MATERIALS

**304-2.1 AGGREGATE.** The aggregate shall be select granular materials,
comprised of crushed or uncrushed gravel and/or stone, or recycled
crushed and graded portland cement concrete (PCC). The material shall be
free of roots, sod, and weeds. The crushed or uncrushed aggregate shall
consist of hard, durable particles of accepted quality, free from an
excess of soft, flat, elongated, or disintegrated pieces, and
objectionable matter. The method used in producing the aggregate shall
be such that the finished product is as consistent as practicable. All
stones and rocks of inferior quality shall be wasted. When recycled PCC
is used as the aggregate, it must meet the requirements for virgin
aggregate.

The percentage of wear of the crushed aggregate retained on the No. 4
(4.75-mm) sieve shall not be greater than 40 percent when tested in
accordance with ASTM C 131. The sodium sulfate soundness loss shall not
exceed 10 percent, or the magnesium sulfate soundness loss shall not
exceed 13 percent, after five cycles, when tested in accordance with
ASTM C 88.

When tested in accordance with ASTM C 136, the aggregate shall conform
to the gradations shown in Table 1. An aggregate blend that meets the
requirements of Table 1 shall be selected by the Contractor and used in
the final mix design. The final aggregate blend shall be well graded
from coarse to fine within the limits designated in the table and shall
not vary from the low limit on one sieve to the high limit on adjacent
sieves, or vice versa. The portion of final aggregate blend passing the
No. 40 (425-µm) sieve shall have a liquid limit of not more than 25 and
a plasticity index of not more than 6 when tested in accordance with
ASTM D 4318.

### Table 1. Aggregate gradation for CTB material. {#table-1.-aggregate-gradation-for-ctb-material. .Style-Heading-3Heading-3-CharHeading-3-Char1-CharHeading-3-Char-...}

  -------------------- ------------------------ --------------------------
  **Sieve Size**       **Percentage by Weight   
                       Passing Sieves**         

                       **Gradation A**          **Gradation B**

  2 in (51 mm)         100 ^1^                  100 ^1^

  No. 4 (4.75 mm)      45 - 100                 55 - 100

  No. 10 (1.80 mm)     37 - 80                  45 - 100

  No. 40 (450 μm)      15 - 50                  25 - 80

  No. 80 (210 μm)      0 - 25                   10 - 35
  -------------------- ------------------------ --------------------------

^1^ Maximum size of aggregate is 1 in (25.4 mm) when used as a base

course under Item P-501, Portland Cement Concrete Pavement.

All aggregate samples required for testing shall be furnished by the
Contractor at the expense of the Contractor. Sampling shall be performed
by the Contractor in accordance with ASTM D 75.

**304-2.2 CEMENT.** Cement shall conform to the requirements of ASTM \[
\].

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> The Engineer shall specify ASTM C 150 Type I, II, III, IV, or V or
> ASTM C 595 Type IS, IS-A, IP, IP-A, P, or PA. Type II cement shall be
> specified in areas with a history of sulfate reaction with the
> selected aggregate.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

**304-2.3 CEMENTITIOUS ADDITIVIES**. Pozzolanic and ground granulated
blast furnace (GGBF) slag may be added to the CTB mix. If used, each
material must meet the following requirements:

a.  Pozzolan. Pozzolanic materials must meet the requirements of ASTM C
    618, Class C, F, or N with the exception of loss of ignition, where
    the maximum shall be less than 6 percent for Class F or N. \[The
    supplementary optional chemical and physical properties of tables 1A
    and 2A contained in ASTM C 618 shall apply\].

b.  GGBF Slag. Slag shall conform to ASTM C 989, Grade 80, 100, or 120.

**304-2.4 WATER**. Water used in mixing or curing shall be clean and
free of oil, salt, acid, alkali, sugar, vegetable, or other deleterious
substances injurious to the finished product. Water shall be tested in
accordance with the requirements of AASHTO T 26. Water known to be of
potable quality may be used without testing.

**304-2.5 CURING MATERIALS**. Curing materials shall conform to the
requirements provided below, as defined by the type of pavement surface
to be placed on top of the CTB layer.

**304-2.5.1 Portland Cement Concrete (PCC) Pavement**. For curing CTB
placed under PCC pavement, use white-pigmented, liquid membrane-forming
compound conforming to ASTM C 309, Type 2, Class A or Class B
(wax-based).

**304-2.5.2 Hot Mix Asphalt (HMA) Pavement**. For curing CTB placed
under HMA pavement, use emulsified asphalt conforming to ASTM C 977 or
ASTM D 2397 (Table 2).

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> If emulsified asphalt is allowed as a curing agent, the Engineer shall
> specify
>
> the type and grade of material to be used and the corresponding
> application temperature from Table 2.

Table 2. Emulsified asphalt curing material.

  ------------------ ------------------- ------------------- -----------------
  **Type and Grade** **Specification**   **Application       
                                         Temperature**       

                                         **°F**              **°C**

  Emulsified Asphalt                                         

  RS-1, SS-1         ASTM D 977          75 - 130            25 - 55

  CRS-1              ASTM D 2397         75 - 130            25 - 55
  ------------------ ------------------- ------------------- -----------------

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

**304-2.6 SAND BLOTTER**. If emulsified asphalt is used as a curing
material, sand shall be applied, when required, for the prevention of
pick-up of emulsion curing materials. The sand material shall be clean,
dry, and non-plastic.

#### COMPOSITION OF MIXTURE

**304-3.1 GENERAL**. The CTB material shall be composed of a mixture of
aggregate, \[Portland cement\] \[blended hydraulic cement\], and water.
Fly Ash or GGBF slag may be used as a partial replacement for Portland
cement.

304-3.2 MIX DESIGN. The mix design shall utilize a cement content that,
when tested in the laboratory according to ASTM D 1633, produces a 7-day
compressive strength meeting the following requirements:

a.  For CTB placed under PCC pavement: 500 psi (3,447 kPa) minimum and
    1,000 psi (6,895 kPa) maximum.

b.  For CTB placed under HMA pavement: 750 psi (5,170 kPa) minimum and
    1,000 psi (6,895 kPa) maximum.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> In areas subject to considerable wet-dry and/or freeze-thaw cycles,
> insert the following statement:
>
> "Wet-dry and/or freeze-thaw tests shall be performed in accordance
> with ASTM D 559 and D 560, respectively. The weight loss for each type
> of test shall not exceed 14 percent after 12 cycles. However, if a
> 7-day compressive strength of 750 psi (5,170 kPa) is achieved, the
> wet-dry and freeze-thaw tests are not necessary."
>
> An estimated cement content may be determined from Table 1, Chapter 2,
> of the Soil-Cement Laboratory Handbook, published by the Portland
> Cement Association (PCA). In designing the mixture, cement contents
> above and below the initial estimated amount should be tested to
> determine the minimum quantity of cement needed to achieve the
> required strength (or strength and durability where freeze-thaw
> resistance is deemed necessary by the Engineer).
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

The mix design shall include a complete list of materials, including
type, brand, source, and amount of cement, fine aggregate, coarse
aggregate, water, and cementitious additives, if used. It shall also
contain the 7-day compressive strength test results and the results of
the wet-dry and/or freeze-thaw tests.

Should a change be made in aggregate sources or type of cement, or if
cementitious additives are added or deleted from the mix, production of
the CTB mix shall be stopped and a new mix design shall be submitted.

**304-3.3 SUBMITTALS.** At least \[ \] days prior to the placement of
the CTB, the Contractor shall submit certified test reports to the
Engineer for those materials proposed for use during construction, as
well as the mix design information for the CTB material. Tests older
than 6 months shall not be used. The certification shall show the ASTM
or AASHTO specifications or tests for the material, the name of the
company performing the tests, the date of the tests, the test results,
and a statement that the material did or did not comply with the
applicable specifications. The submittal package shall include the
following:

a.  Sources of materials, including aggregate, cement, cementitious
    additives, curing, and bond-breaking materials.

b.  Physical properties of the aggregates, cement, cementitious
    additives, curing, and bond-breaking materials.

c.  Mix design

    -   mix identification number.

    -   aggregate gradation.

    -   cement content.

    -   water content.

    -   cementitious materials content.

> d\. Laboratory test results

-   compaction and strength testing procedures.

-   laboratory compaction characteristics (maximum dry density and
    optimum moisture content).

-   compressive strength at 7 days.

-   Wet-dry and/or freeze-thaw weight loss, if applicable.

No CTB material shall be placed until the submittal is accepted in
writing by the Engineer.

During production, the Contractor shall submit batch tickets for each
delivered load.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> Insert the appropriate number of days for Contractor submittal of
> certified test reports for the proposed materials; 10 to 20 days is
> typical.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

#### EQUIPMENT

All equipment necessary to mix, transport, place, compact, and finish
the CTB material shall be furnished by the Contractor. The equipment
shall be inspected and approved by the Engineer at the job site prior to
the start of construction operations.

**304-4.1 MIXING.** The mixer shall be a batch or continuous-flow type
stationary mixer and shall be equipped with calibrated metering and
feeding devices that introduce the aggregate, cement, water, and
cementitious additives (if used) into the mixer in the specified
quantities. If necessary, a screening device shall be used to remove
oversized material greater than 2 in (51 mm) from the raw aggregate feed
prior to mixing.

Free access to the plant must be provided at all times for inspection of
the plant's equipment and operation and for sampling the CTB mixture and
its components, as deemed necessary by the Engineer.

**304-4.2 HAULING**. The mixed CTB material shall be transported from
the plant to the job site in trucks or other hauling equipment having
beds that are smooth, clean, and tight. Truck bed covers shall be
provided and used to protect the CTB from rain. CTB material that
becomes wet during transport shall be subject to rejection.

**304-4.3 PLACING**. CTB material shall be placed using a mechanical
spreader or a machine capable of receiving, spreading, and shaping the
mixture without segregation into a uniform layer or lift. The equipment
shall be equipped with a strike-off plate capable of being adjusted to
the specified layer thickness. It shall also be equipped with two end
gates or cut off plates, so that the CTB may be spread in widths varying
up to lane width.

**304-4.4 COMPACTION**. Compaction of the CTB layer shall be
accomplished using one or a combination of the following pieces of
equipment:

-   Tamping or grid roller.

-   Steel-wheeled roller

-   Vibratory roller.

-   Pneumatic-tire roller.

-   Vibrating plate compactor (for areas inaccessible to rollers).

The number, type, and weight of rollers and/or compactors shall be
sufficient to compact the mixture to the required density.

**304-4.5 FINISHING**. Final trimming of the compacted CTB to meet
surface requirements shall be accomplished using a self-propelled grader
or trimming machine, with a mold board cutting edge, which is at least
12 ft (3.7 m) wide and is automatically controlled by sensors in
conjunction with an independent grade control from a taut stringline.
Stringline will be required on both sides of the sensor controls for the
pilot lane. For all other lanes, a single stringline on the outside and
grade matching with previously completed adjacent lanes is permissible.

# 

#### CONSTRUCTION METHODS

**304-5.1 WEATHER LIMITATIONS**.

**304-5.1.1 Cold Weather***.* The CTB material shall not be mixed or
placed while the air temperature is below 40°F (4°C) or when conditions
indicate that the temperature may fall below 35°F (2°C) within 24 hours.
The CTB shall not be placed on frozen surfaces.

**304-5.1.1 Rain***.* The CTB may not be placed when rainfall is
occurring. If an unexpected rain event occurs during placement, the
layer should be quickly compacted. CTB material that becomes wet by rain
during transport or placement shall be evaluated by the Engineer, and
may be subject to rejection.

**304-5.2 PREPARATION OF UNDERLYING COURSE**. The underlying course
shall be checked by the Engineer before placing and spreading operations
are started, in order to ensure that it is free of any ruts,
depressions, or bumps and is finished to the correct grade. Any ruts or
soft yielding places caused by improper drainage conditions, hauling, or
any other cause, shall be corrected before the CTB mixture is placed
thereon. The underlying course shall be wetted in advance of placing the
CTB layer. The final prepared grade prior to placing the CTB should be
in a firm and moist condition free of frost. Use of chemicals to
eliminate frost will not be permitted.

To ensure proper drainage, placement of the base shall begin along the
centerline of the pavement on a crowned section or on the highest
elevation contour of a pavement with variable cross slope.

**304-5.3 GRADE CONTROL**. Grade control between the edges of the CTB
shall be accomplished at intervals of 50 ft (15.2 m) or less on the
longitudinal grade and at 25 ft (7.6 m) or less on the transverse grade.

**304-5.4 HANDLING, MEASURING, AND BATCHING**. The continuous flow
central plant site, layout, equipment, and provisions for transporting
material shall assure a

continuous supply of material to the work. Aggregate stockpiles shall be
constructed in a manner that prevents segregation and intermixing of
deleterious materials.

Aggregates that are segregated or mixed with earth or foreign material
will not be accepted.

Continuous flow plants shall be equipped with feeders to proportion
aggregates and bulk cement, by weight, automatically and accurately.
When bulk cement is used, the Contractor shall use a suitable method of
handling the cement from weighing hopper to transporting container or
into the batch itself for transportation to the mixer, such as a chute,
boot or other device, to prevent loss of cement. The device shall be
arranged to provide positive assurance that the cement content specified
is present in each batch.

**304-5.5 MIXING**. Aggregate and cement may be proportioned either by
weight or volume, and shall be mixed sufficiently to prevent the forming
of cement balls when water is added. The mixing time shall be that which
is required to secure an intimate, uniform mixture of aggregate, cement,
water, and pozzolan (if used). The minimum mixing time will be based on
the uniformity and consistency of the mixture.

**304-5.6 PLACING.** The CTB mixture shall be deposited on the moistened
subgrade or subbase and spread into a uniform layer of such width and
thickness that, following compaction and trimming, conforms to the
required grade and cross-section. The Contractor may install the CTB
layer in single or multiple compacted lifts; however, each compacted
lift must be no greater than 6 in (152 mm) thick. In multi-lift
construction, the surface of the compacted lift shall be kept moist
until covered with the next lift. Successive lifts shall be placed and
compacted so that the required total depth of the CTB layer is completed
within 12 hours.

A single spreader may be used, provided it is capable of placing a
uniform, full-depth layer of material across the full width of the base
in one pass. Otherwise, two or more spreaders will be required, and
shall be operated so that spreading progresses along the full width of
the base in a uniform manner.

**304-5.7 COMPACTION**. Immediately upon completion of the spreading
operations, the CTB material shall be thoroughly compacted using
approved compaction equipment. At the start of compaction, the moisture
content shall be within 2 percentage points of the specified optimum
moisture.

**304-5.8 FINISHING.** Upon completion of compaction, the surface of the
CTB layer shall be shaped to the specified lines, grades, and
cross-section. During the finishing process, the surface shall be kept
moist by means of fog-type sprayers. Compaction and finishing shall be
done in such a manner as to produce a smooth, dense surface, free of
ruts, cracks, ridges, and loose material. All placement, compaction, and
finishing operations shall be completed within 2 hours from the start of
mixing. Material not completed within the 2-hour time limit shall be
removed and replaced at the Contractor's expense.

CTB layer limits that extend beyond the edges of the new PCC surface
course shall be rolled down or shaped in such a manner that the drainage
is away from the new PCC surface course edge.

**304-5.9 CONSTRUCTION JOINTS**. At the end of each day\'s construction,
a transverse construction joint shall be formed that is a true vertical
face (perpendicular to the centerline) and is free of loose material.

Longitudinal construction joints (parallel to the centerline) shall be
formed to a consistent, well-defined near vertical edge that is free of
loose material. The longitudinal joints shall be located such that there
is a 2-ft (0.6-m) minimum offset from planned joints in any overlying
layer.

While forming construction joints, the Contractor shall make sure the
material in the joint area is adequately compacted and that the joints
are finished level and even with the remainder of the CTB layer.

**304-5.10 CURING.** The compacted and finished CTB shall be cured with
the approved curing agents as soon as possible, and in no case later
than 2 hours after completion of the finishing operations. The layer
shall be kept moist using a moisture-retaining cover or a light
application of water until the curing material is applied.

When asphalt emulsion is used as the curing agent, the entire surface of
the CTB layer shall be uniformly sprayed with the emulsion at a rate of
between 0.15 and 0.30 gal/yd^2^ (0.7 and 1.4 L/m^2^); the exact
temperature and rate of application being that required to achieve
complete and uniform coverage without runoff. Should it be necessary for
construction equipment or other traffic to use the asphalt-covered
surface, sufficient sand blotter cover shall be applied to prevent
pick-up.

When liquid membrane-forming curing compound is used as the curing
agent, the entire surface of the CTB layer shall be uniformly sprayed
with the compound at the rate of 1 gal (3.8 L) to not more than 200
ft^2^ (18.6 m^2^). The rate of application shall be determined such that
a uniform surface is obtained. The spraying equipment shall be of the
fully atomizing type equipped with a tank agitator. The compound shall
be thoroughly mixed with the pigment uniformly dispersed throughout the
storage tank. During application, the compound shall be stirred
continuously by effective mechanical means. Hand spraying of odd widths
or shapes and CTB surfaces exposed by the removal of forms is permitted.

The curing seal shall be maintained and protected until the pavement is
placed. Should the surface of the finished CTB and/or the curing seal
become damaged, additional curing material shall be applied at the time
it is damaged or when the damage is first observed.

**304-5.11 PROTECTION**. The Contractor shall protect the finished CTB
against traffic. Completed portions of the CTB layer can be opened
immediately to low-speed traffic and to construction equipment, provided
the curing material is not damaged and the CTB is sufficiently stable to
resist permanent deformation. Should the CTB be damaged, it shall be
replaced using full-depth patches, and sprayed with the selected curing
compound as described above. The CTB shall also be protected from
freezing at all times.

**304-5.12 BOND-BREAKER.** When the CTB is to be placed directly beneath
PCC, a bond-breaker selected by the Contractor shall be used. The entire
surface of the CTB shall be coated with a de-bonding compound applied in
a quality sufficient to prevent bonding of the PCC pavement to the base
course. If an impervious membrane or asphalt emulsion is used as a
curing material, additional applications of curing materials may be
required. The Contractor shall be responsible for selecting the
de-bonding compound and determining the necessary application rate. The
de-bonding compound shall be approved by the Engineer prior to being
incorporated into the work.

#### MATERIAL ACCEPTANCE

**304-6.1 ACCEPTANCE SAMPLING AND TESTING**. All acceptance sampling and
testing, with the exception of thickness determination, necessary to
determine conformance with the requirements specified in this section
will be performed by the Engineer. The Contractor shall provide the
required CTB samples during construction for acceptance testing
purposes. The samples shall be taken in the presence of the Engineer.

Testing organizations performing these tests shall meet the requirements
of ASTM D 3666. All test equipment in Contractor-furnished laboratories
shall be calibrated by the testing organization prior to the start of
operations.

The CTB layer shall be tested for density, thickness, grade, and surface
tolerance on a lot basis, with a lot consisting of one of the following:

-   One day's production not to exceed \[2,000 yd^2^ (1,675 m^2^)\].

-   A half day's production, where a day's production consists of
    \[2,000 to 4,000 yd^2^ (1,675 to 3,350 m^2^)\].

Each lot shall be divided into four (4) equal sublots. Within each
sublot, one (1) density test, one (1) thickness measurement, and
continuous surface straightedge tests (surface tolerance testing) shall
be performed, as described below. Sampling locations shall be determined
by the Engineer in accordance with the random sampling procedures
contained in ASTM D 3665.

In the event that only three (3) sublots are produced, the three sublots
shall constitute a complete lot. If one (1) or two (2) sublots are
produced for the same reason, they shall be incorporated into the next
or previous lot, and the total number of sublots shall be used in the
acceptance criteria calculation.

End-of-production sublots (i.e., sublots associated with the final
placement of CTB for the project and are less than a complete lot) shall
be handled as follows:

-   Three (3) sublots shall constitute a lot.

-   One (1) or two (2) sublots shall be incorporated into the previous
    lot.

**304-6.1.1 Density Testing.** CTB samples shall be taken from each
sublot and used to create laboratory test specimens representing the
various sublots. The specimens shall be compacted and tested for density
and moisture content in accordance with ASTM D 558. Using the density
results for each sublot comprising a lot, an average density for the lot
shall be determined, which will serve as the basis for acceptance of the
lot with regard to density.

Within each sublot in the field, one (1) in-place density test shall be
performed in accordance with ASTM D 1556, ASTM D 2167, or ASTM D 2922
and ASTM D 3017. The location of the test shall be randomly selected in
accordance with the procedures contained in ASTM D 3665. The in-place
density results for each sublot comprising the lot shall then be
averaged and compared with the corresponding average lot density.
Acceptance criteria for CTB density are provided in paragraph 304-6.2.1.

**304-6.1.2 Thickness Testing.** The CTB shall be tested for thickness
using the same lot and sublot designations established for density
testing. After 3 days of curing, one (1) 4-in (102-mm) diameter core per
sublot shall be obtained from a random location, as identified using the
procedures contained in ASTM D 3665. The thickness of each sampled core
shall be determined using the caliper measurement procedures provided in
ASTM C 174. The average thickness for the lot shall be determined using
the individual sublot core thicknesses. Acceptance criteria for CTB
thickness are provided in paragraph 304-6.2.2. At all locations where
cores have been drilled, the resulting core holes shall be filled by the
Contractor with CTB, HMA, or non-shrink grout.

**304-6.1.3 Grade Testing**. The elevations of the finished CTB shall be
surveyed every 25 ft (7.6 m) on both sides of the CTB lane as soon as it
has hardened sufficiently. Acceptance criteria for CTB grade are
provided in paragraph 306-6.2.3.

**304-6.1.4 Surface Tolerance Testing**. As soon as the CTB has hardened
sufficiently, it shall be tested for surface tolerance with a 16-ft
(4.9-m) straightedge or other approved measuring device.

**304-6.2 ACCEPTANCE CRITERIA**. Acceptance of CTB will be based on
density, thickness, grade, and surface tolerance, as described in the
paragraphs below.

**304-6.2.1 Density Requirements**. With respect to density, each lot of
compacted material will be accepted without adjustment if the average
in-place density of the lot is equal to or greater than 98 percent of
the average density determined for the lot. Each lot of compacted CTB
shall be accepted and payment adjusted in accordance with Table 3.

Table 3. Sliding pay scale factors for density.

  --------------------------------------- -------------------------------
  **Average Dry Density (%)**             **Payment (%)**

  98.0 and greater                        100

  97.0 - 97.9                             95

  96.0 - 96.9                             90

  95.0 - 95.9                             75

  Less than 95.0                          Reject
  --------------------------------------- -------------------------------

If the average density is below 95 percent, the lot will be rejected and
shall be removed and replaced at the Contractor's expense. In
multi-layer construction, density shall be tested for each lift, and all
lifts within a rejected lot shall be removed and replaced. No payment
shall be made for removed lifts. Replacement lifts shall be paid in
accordance with this section.

**304-6.2.2 Thickness Requirements**. The completed thickness shall be
as shown on the plans. When the average lot thickness is not deficient
by more than ½ in (12.5 mm) from the plan thickness, full payment shall
be made. If the average lot thickness is deficient by more than 1 in
(25.4 mm), it shall be removed and replaced at the Contractor's expense.
When such measurement is deficient by more than ½ in (12.5 mm) but less
than 1 in (25.4 mm) from the plan thickness, one additional core shall
be taken at random from each sublot within the lot. The thickness of
these additional cores shall be determined as indicated in paragraph
304-6.1.2. A new average lot thickness shall be recomputed based on
these additional cores and the original cores taken from each sublot. If
the recomputed average lot thickness is not deficient by more than ½ in
(12.5 mm) from the plan thickness, full payment shall be made. If the
average lot thickness is deficient by more than ½ in (12.5 mm) from the
plan thickness, the entire lot shall be removed and replaced at the
Contractor\'s expense or shall be permitted to remain in-place at an
adjusted payment of 75 percent of the contract unit price.

When the measured thickness is more than that indicated on the plans, it
will be considered as conforming to the requirements, provided the
surface of the completed CTB layer is within the established grade and
surface tolerance requirements.

**304-6.2.3 Grade Requirements**. When the completed surface is higher
than ½ in (12.5 mm) above the grade shown in the plans, the surface
shall be trimmed, at the Contractor's expense, with an approved grinding
machine to an elevation that falls within a tolerance of ¼ in (6 mm) or
less.

**304-6.2.4 Surface Tolerance Requirements**. The finished surface shall
not vary more than ⅜ in (9.5 mm) when tested with a 16-ft (4.9-m)
straightedge applied parallel with, or at right angles to, the
centerline of the CTB area. Areas in the CTB showing high spots greater
than ⅜ in (9.5 mm) over 16 ft (4.9 m) shall be marked and immediately
trimmed with an approved grinding machine. Such trimming shall be at the
Contractor's expense.

#### METHOD OF MEASUREMENT

**304-7.1 CEMENT-TREATED BASE COURSE**. The quantity of cement-treated
base course to be paid for will be determined by measurement of the
number of \[yd^2^ (m^2^)\] of CTB actually constructed and accepted by
the Engineer as complying with the plans and specifications.

#### BASIS OF PAYMENT

**304-8.1 CEMENT-TREATED BASE COURSE**. Payment shall be made at the
contract unit price per \[yd^2^ (m^2^)\] for cement-treated base course.
This price shall be full compensation for furnishing all materials,
including cement; for all preparation, manipulation, placing, and curing
of these materials; and for all labor, equipment, tools, and incidentals
necessary to complete the item.

Each lot of CTB material will be accepted for density at the full
contract price adjusted in accordance with Table 3 in paragraph
304-6.2.1.

Payment will be made for cement-treated base course\--per \[yd^2^
(m^2^)\].

# 

#### TESTING REQUIREMENTS

ASTM C 88 Soundness of Aggregates by Use of Sodium Sulfate or

Magnesium Sulfate

ASTM C 131 Resistance to Degradation of Small-Size Coarse Aggregate

by Abrasion and Impact in the Los Angeles Machine

ASTM C 136 Sieve or Screen Analysis of Fine and Coarse Aggregate

ASTM C 174 Measuring Thickness of Concrete Elements Using Drilled

Concrete Cores

ASTM D 75 Sampling Aggregates

ASTM D 558 Moisture-Density Relations of Soil-Cement Mixtures

ASTM D 559 Test Methods for Wetting & Drying Compacted Soil Cement

Mixtures

ASTM D 560 Freezing-and-Thawing Tests of Compacted Soil-Cement Mixtures

ASTM D 1556 Density of Soil in Place by the Sand-Cone Method

ASTM D 1633 Compressive Strength of Molded Soil-Cement Cylinders

ASTM D 2167 Density of Soil in Place by the Rubber-Balloon Method

ASTM D 2922 Density of Soil and Soil-Aggregate in Place by Nuclear
Methods

ASTM D 3017 Water Content of Soil and Rock in Place by Nuclear Methods

ASTM D 3665 Random Sampling of Paving Materials

ASTM D 3666 Minimum Requirements for Agencies Testing and Inspecting

Road and Paving Materials

ASTM D 4318 Liquid Limit, Plastic Limit, and Plasticity Index of Soils

AASHTO T 26 Quality of Water to be Used in Concrete

#### MATERIAL REQUIREMENTS

ASTM C 150 Portland Cement

ASTM C 309 Liquid Membrane-Forming Compounds for Curing Concrete

ASTM C 595 Blended Hydraulic Cements

ASTM C 618 Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as
a

Mineral Admixture in Concrete

ASTM C 989 Ground Granulated Blast-Furnace Slag for Use in Concrete

and Mortars

ASTM D 977 Emulsified Asphalt

ASTM D 2397 Cationic Emulsified Asphalt

**End P-304**

### **ITEM P-306 ECONOCRETE BASE COURSE**

#### 

#### DESCRIPTION

**306-1.1** This item shall consist of a subbase material, herein termed
econocrete, that is composed of aggregate and cement uniformly blended
together and mixed with water. The mixture may also include approved
cementitious additives, in the form of fly ash or slag, and chemical
admixtures. The mixed material shall be spread, shaped, and consolidated
using concrete paving equipment in accordance with these specifications
and in conformity to the lines, grades, dimensions, and typical
cross-sections shown on the plans.

#### MATERIALS

**306-2.1 AGGREGATE**. The coarse aggregate fraction shall be crushed
stone, crushed or uncrushed gravel, crushed and adequately seasoned,
air-cooled, iron blast furnace slag, crushed recycled concrete, or a
combination thereof. The fine aggregate fraction may be part of the
natural aggregate blend as obtained from the borrow source or it may be
natural sand that is added at the time of mixing.

The aggregate shall consist of hard, durable particles, free from an
excess of flat, elongated, soft, or disintegrated pieces, or
objectionable matter (e.g., roots, sod, weeds, organic impurities,
etc.). A flat particle is one having a ratio of width to thickness
greater than five; an elongated particle is one having a ratio of length
to width greater than five.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> The Engineer should specify limits for deleterious materials using
> guidance contained in ASTM C 33.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

The design aggregate blend shall conform to one of the gradations shown
in Table 1, when tested in accordance with ASTM C 136.

Table 1. Aggregate gradation for econocrete.

+--------------------+------------------------+------------------------+
| **Sieve Size**     | **Percentage by Weight |                        |
|                    | Passing Sieves**       |                        |
| **(square          |                        |                        |
| openings)**        |                        |                        |
+--------------------+------------------------+------------------------+
|                    | **1½ -in (37.5-mm)     | **1-in (25-mm)         |
|                    | Maximum**              | Maximum**              |
+--------------------+------------------------+------------------------+
| 2 in (51 mm)       | \--                    | \--                    |
|                    |                        |                        |
| 1½ in (37.5 mm)    | 100                    | \--                    |
|                    |                        |                        |
| 1 in (25 mm)       | 70 - 95                | 100                    |
|                    |                        |                        |
| ¾ in (19 mm)       | 55 - 85                | 70 - 100               |
|                    |                        |                        |
| No. 4 (4.75 mm)    | 30 - 60                | 35 - 65                |
|                    |                        |                        |
| No. 40 (425 µm)    | 10 - 30                | 15 - 30                |
|                    |                        |                        |
| No. 200 (75 µm)    | 0 - 15                 | 0 -- 15                |
+--------------------+------------------------+------------------------+

**306-2.2 CEMENT**. Cement shall conform to the requirements of ASTM \[
\].

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> The Engineer shall specify ASTM C 150 Type I, II, III, IV, or V or
> ASTM C 595 Type IS, IS-A, IP, IP-A, P, or PA. Type II cement shall be
> specified in areas with a history of sulfate reaction with the
> selected aggregate.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

**306-2.3 CEMENTITIOUS ADDITIVES**. Pozzolanic and ground granulated
blast furnace (GGBF) slag may be added to the econocrete mix. If used,
each material must meet the following requirements:

a.  Pozzolan. Pozzolanic materials must meet the requirements of ASTM C
    618, Class F Flyash.

b.  Ground Granulated Blast Furnace Slag (Slag Cement). Slag shall
    conform to ASTM C 989, Grade 80, 100 or 120.

**306-2.4 CHEMICAL ADMIXTURES.** The Contractor shall submit
certificates indicating that the material to be furnished meets all the
requirements listed below. In addition, the Engineer may require the
Contractor to submit complete test data showing that the material to be
furnished meets all the requirements of the cited specification.

a.  Air-Entraining Admixtures. Air-entraining admixtures shall meet the
    requirements of ASTM C 260.

b.  Water-Reducing Admixtures. Water-reducing, set-controlling
    admixtures shall meet the requirements of ASTM C 494, Type A,
    water-reducing or Type D, water-reducing and retarding.
    Water-reducing admixtures shall be added at the mixer separately
    from air-entraining admixtures in accordance with the
    manufacturer\'s printed instructions. The air entrainment agent and
    the water-reducing admixture shall be compatible.

**306-2.5 WATER**. Water used in mixing or curing shall be clean and
free of oil, salt, acid, alkali, sugar, vegetable, or other deleterious
substances injurious to the finished product. Water will be tested in
accordance with the requirements of AASHTO T 26. Water known to be of
potable quality may be used without testing.

**306-2.6 CURING MATERIALS**. For curing econocrete, use
white-pigmented, liquid membrane-forming compound conforming to ASTM C
309, Type 2, Class A or Class B (wax-based) or Asphalt emulsion
conforming to the requirements of ASTM D 977, Type SS-1h..

**\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \***

**The Engineer may add additional curing materials Modify the Bond
Breaker paragraph accordingly.**

**\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \***

#### COMPOSITION OF MIXTURE

**306-3.1 MIX DESIGN**. The econocrete mix design shall be based on
trial batch results conducted in the laboratory. The econocrete shall be
designed to meet the criteria in this section.

**306-3.1.1 Compressive Strength***.* Compressive strength shall not be
less than 500 psi (3,445 kPa) nor greater than 800 psi (5,516 kPa) at 7
days. 3-day and 7-day strengths shall be taken as the average of two
compressive strength test results. All compressive strength specimens
shall be prepared and tested in accordance with ASTM C 192 and ASTM C
39, respectively.

If the 3-day strength is greater than 500 psi (3,447 kPa), the
Contractor shall construct transverse joints in the econocrete layer in
accordance with paragraph 306-5.10.2.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> In locations subject to freeze-thaw cycles, insert the following "The
> freeze-thaw weight loss shall not exceed 14 percent when tested in
> accordance with ASTM D 560."
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

If there is a change in aggregate sources, type of cement used, or
pozzolanic materials, a new mix design must be submitted.

**306-3.1.2 Air Content.** The percentage of air entrainment shall be 6
percent, plus or minus 1/2 percent. Air content shall be determined by
testing in accordance with ASTM C 231 for gravel and stone coarse
aggregate and ASTM C 173 for slag and other highly porous coarse
aggregate.

**306-3.2 SUBMITTALS**. At least \[ \] days prior to the placement of
the econocrete, the Contractor shall submit certified test reports to
the Engineer for those materials proposed for use during construction,
as well as the mix design information for the econocrete material. Tests
older than 6 months shall not be used. The certification shall show the
appropriate ASTM or AASHTO specifications or tests for the material, the
name of the company performing the tests, the date of the tests, the
test results, and a statement that the material did or did not comply
with the applicable specifications. The submittal package shall include
the following:

a.  Sources of materials, including aggregate, cement, admixtures, and
    curing and bond breaking materials.

b.  Physical properties of the aggregates, cement, admixtures, curing
    and bond breaking materials.

c.  Mix design.

-   mix identification number.

-   weight of saturated surface-dry aggregates (fine and coarse).

-   combined aggregate gradation.

-   cement factor.

-   water content.

-   water-cementitious material ratio (by weight).

-   volume of admixtures and yield for one cubic yard (cubic meter) of
    econocrete.

d.  Laboratory test results.

-   slump.

-   air content.

-   compressive strength at 3, 7, and 28 days (average values).

-   wet/dry and/or freeze-thaw weight loss (when applicable).

In addition, where applicable, the Contractor shall submit for approval
by the Engineer a jointing plan for transverse joints in the econocrete
layer.

During production, the Contractor shall submit batch tickets for each
delivered load.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> Insert the appropriate number of days for Contractor submittal of the
> certified test reports and the mix design; 15 to 30 days is typical.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

# 

#### EQUIPMENT

**306-4.1** All equipment necessary to mix, transport, place, compact,
and finish the econocrete material shall be furnished by the Contractor.
The equipment shall be subject to inspection and approval by the
Engineer.

**306-4.2 MIXING.** Econocrete may be mixed in a stationary mixer,
either at a central batch plant or at the site, or in a truck mixer. The
mixer type and capacity shall be inspected and approved by the Engineer
before production begins. Each mixer shall have attached in a prominent
place a manufacturer\'s nameplate showing the capacity of the drum in
terms of volume of mixed concrete and the speed of rotation of the
mixing drum or blades.

306-4.2.1 Stationary Plant Mixer***.*** The batch plant and equipment
shall conform to the requirements of ASTM C 94. Unrestricted access to
the plant must be provided to the Engineer at all times for inspection
of the plant's equipment and operation and for sampling the econocrete
mixture and its components.

The mixers shall be examined daily for changes in condition due to
accumulation of hard concrete or mortar or wear of blades.

**306-4.2.2 Truck Mixers***.* Truck mixers used for mixing econocrete
shall conform to the requirements of ASTM C 94. Econocrete may be
entirely mixed in a truck mixer or partially mixed in a stationary mixer
with mixing completed in a truck mixer. Truck mixers shall be equipped
with an accurate continuous registering electronically or mechanically
activated revolution counter, by which the number of drum revolutions
may be verified.

**306-4.3 HAULING.** Mixed econocrete shall be hauled from the
stationary plant to the job site in a truck agitator, a truck mixer
operating at agitating speed, or a non-agitating truck. All equipment
shall conform to the requirements of ASTM C 94. When truck mixers are
used to mix econocrete, they may be transported to the job site in the
same truck operating at agitating speeds, truck agitators, or a
non-agitating truck. The bodies of non-agitating trucks shall be smooth,
metal containers and shall be capable of discharging the concrete at a
satisfactory controlled rate without segregation.

**306-4.4 PLACING AND FINISHING**.

**306-4.1 Forms.** Straight side forms shall be made of steel and shall
be furnished in sections not less than 10 ft (3.1 m) in length. Forms
shall have a depth equal to the pavement thickness at the edge. Flexible
or curved forms of proper radius shall be used for curves of 100-ft
(31-m) radius or less. Forms shall be provided with adequate devices for
secure settings so that when in place they will withstand, without
visible spring or settlement, the impact and vibration of the
consolidating and finishing equipment. Forms with battered top surfaces
and bent, twisted or broken forms shall not be used. Built-up forms
shall not be used, except as approved by the Engineer.

The top face of the form shall not vary from a true plane more than ⅛ in
(3 mm) in 10 ft (3.1 m), and the upstanding leg shall not vary more than
¼ in (6 mm). The forms shall contain provisions for locking the ends of
abutting sections together tightly for secure setting. Wood forms may be
used under special conditions, when accepted by the Engineer.

**306-4.4.2 Pavers.** Econocrete can be placed using fixed forms or
slip-form pavers. The paver shall be fully energized, self-propelled and
capable of spreading, consolidating, and finishing the econocrete
material, true to grade, tolerances, and cross sections. The paver shall
be capable of finishing the surface so that hand finishing is not
required. The paver shall be of sufficient weight and power to construct
the maximum specified concrete paving lane width, at adequate forward
speed, without transverse, longitudinal or vertical instability or
without displacement. The slip-form paver shall be equipped with
electronic or hydraulic horizontal and vertical control devises
utilizing guide wires or stringlines on both sides of the machine. Slope
control will not be allowed.

a.  Concrete Pavers. Concrete pavers are approved as paver-finishing
    machines for econocrete, providing they are capable of handling the
    amount of econocrete required for the full-lane width specified, and
    consolidating the econocrete full depth. A concrete paver is a
    power-driven machine with augers, strike-off and tamper bars ahead
    of a pan screed, with at least one trailing oscillating screed or
    belt finisher.

b.  Bridge Deck Pavers. Bridge deck pavers are approved as
    paver-finishing machines for econocrete, providing they are capable
    of handling the amount of econocrete required for the full-lane
    width specified, and consolidating the econocrete full depth. A
    bridge deck paver is an automatic truss paving machine, with paving
    carriage that strikes off, vibrates, paves, and textures the
    econocrete with augers, internal vibration, paving rollers, and drag
    pan.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> Econocrete is a weak concrete mix. As such, it should be placed with
> pavers suitable for paving concrete pavements. Rotating pipe and tube
> floats are not suitable for this type of pavement.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

**306-4.5 CONSOLIDATION**. For side-form construction, vibrators may be
either the surface pan type for pavements less than 8 in (203 mm) thick
or the internal type with either immersed tube or multiple spuds for the
full width of the slab. They may be attached to the spreader or the
finishing machine, or they may be mounted on a separate carriage. They
shall not come in contact with the joint, subgrade, or side forms.

For slip-form construction, the paver shall vibrate the econocrete for
the full width and depth of the strip of pavement being placed.
Vibration shall be accomplished by internal vibrators.

The number, spacing, frequency, and eccentric weights of vibrators shall
be provided as necessary to achieve acceptable consolidation without
segregation and finishing quality. Adequate power to operate all
vibrators at the weight and frequency required for a satisfactory finish
shall be available on the paver. The internal vibrators may be
supplemented by vibrating screeds operating on the surface of the
econocrete. The Contractor shall constantly monitor the frequency of
each of the individual vibrators using electronic means and shall
provide constant monitoring of the consolidation process to avoid
honeycombing or segregation. Areas that are visually determined to be
honeycombed or over-consolidated shall be corrected at the Contractor's
expense.

The vibrators and tamping elements shall be automatically controlled so
that they stop operation as forward motion ceases. Any override switch
shall be of the spring-loaded, momentary-contact type.

Hand held vibrators may be used in irregular areas.

**306-4.6 JOINTING.** The Contractor shall provide sawing equipment
adequate in number of units and power to produce contraction or
construction joints of the required dimensions as shown on the plans.
The Contractor shall provide at least one standby saw in good working
order and a supply of saw blades at the site of the work at all times
during sawing operations.

#### CONSTRUCTION METHODS

306-5.1 WEATHER LIMITATIONS.

**306-5.1.1 Cold Weather***.* Unless authorized by the Engineer, the
temperature of the mixed econocrete shall not be less than 50°F (10°C)
at the time of placement. In addition, the econocrete shall not be
placed when the ambient temperature is below 40°F (4°C) or when
conditions indicate that the temperature may fall below 35°F (2°C)
within 24 hours. Under no circumstances shall the econocrete be placed
on frozen underlying courses or mixed when the aggregate is frozen.

When mixing and placing is authorized during cold weather, the Engineer
may require the water and/or the aggregates to be heated to not less
than 70°F (20°C) nor more than 150°F (66°C). The aggregates may be
heated by either steam or dry heat prior to being placed in the mixer.
The apparatus used shall heat the mass uniformly and shall be arranged
to preclude the possible occurrence of overheated areas which might be
detrimental to the materials.

**306-5.1.2 Hot Weather***.* To prevent rapid drying of newly
constructed econocrete, the econocrete temperature from initial mixing
through final cure shall not exceed 90°F (32°C). The aggregates and/or
mixing water shall be cooled as necessary to maintain the econocrete
temperature at or not more than the specified maximum. Ice or ice water
may be substituted for the mixing water for this purpose.

In addition, during periods of warm weather when the maximum daily air
temperature exceeds 85°F (30°C), the forms and/or the underlying
material shall be sprinkled with water immediately before placing the
econocrete.

**306-5.1.3 Rain***.* All mixing and batching operations should be
halted during rain showers and any plastic econocrete placed should be
covered immediately. The econocrete shall be kept covered with plastic
sheeting or other waterproof material until such time that the rain does
not make any surface indentation on the econocrete layer. Areas damaged
by rain shall be refinished or replaced.

**306-5.2 FORM SETTING**. Forms shall be set sufficiently in advance of
the econocrete placement to ensure continuous paving operation. After
the forms have been set to correct grade, the grade shall be thoroughly
tamped, either mechanically or by hand, at both the inside and outside
edges of the base of the forms. Forms shall be staked into place with
not less than 3 pins for each 10-ft (3.1-m) section. A pin shall be
placed at each side of every joint.

Form sections shall be tightly locked and shall be free from play or
movement in any direction. The forms shall not deviate from true line by
more than ¼ in (6 mm) at any joint. Forms shall be so set that they will
withstand, without visible spring or settlement, the impact and
vibration of the consolidating and finishing equipment. Forms shall be
cleaned and oiled prior to the placing of econocrete.

The alignment and grade elevations of the forms shall be checked and
corrections made by the Contractor immediately before placing the
econocrete. When any form has been disturbed or any grade has become
unstable, the form shall be reset and rechecked.

**306-5.3 PREPARATION OF UNDERLYING COURSE**. The underlying course
shall be checked by the Engineer before placing and spreading operations
are started, in order to ensure that it is free of any ruts,
depressions, or bumps and is finished to the correct grade. Any ruts or
soft yielding places in the underlying course caused by improper
drainage conditions, hauling, or any other cause, shall be corrected at
the Contractor's expense before the econocrete mixture is placed
thereon. The underlying course should be wetted down in advance of
placing the econocrete to ensure a firm, moist condition at the time of
econocrete placement. The underlying course shall be protected from
frost. Usage of chemicals to eliminate frost is not permissible.

**306-5.4 GRADE CONTROL**. Grade control between the edges of the
pavement shall be accomplished at intervals of 50 ft (15.3 m) or less on
the longitudinal grade and at 25 ft (7.6 m) or less on the transverse
grade. To protect the underlying course and ensure proper drainage, the
econocrete paving shall begin along the centerline of the pavement on a
crowned section or on the greatest contour elevation of a pavement with
variable cross slope.

**306-5.5 HANDLING, MEASURING, AND BATCHING MATERIAL.** The batch plant
site, layout, equipment, and provisions for transporting material shall
assure a

continuous supply of material to the work. Stockpiles shall be
constructed in a manner that prevents segregation and intermixing of
deleterious materials.

Aggregates that have become segregated or mixed with earth or foreign
material shall not be used. All aggregates produced or handled by
hydraulic methods, and washed aggregates, shall be stockpiled or binned
for draining at least 12 hours before being batched. Rail shipments
requiring more than 12 hours transit will be accepted as adequate
binning only if the car bodies permit free drainage.

Batching plants shall be equipped to proportion aggregates and bulk
cement, by weight, automatically using interlocked proportioning devised
of an approved type. When bulk cement is used, the Contractor shall use
a suitable method of handling the cement from weighing hopper to
transporting container or into the batch itself for transportation to
the mixer, such as a chute, boot or other device approved by the
Engineer, to prevent loss of cement. The device shall be arranged to
provide positive assurance that the required cement content is present
in each batch.

**306-5.6 MIXING.** All econocrete shall be mixed and delivered to the
site in accordance with the requirements of ASTM C 94. The mixing time
should be adequate to produce econocrete that is uniform in appearance,
with all ingredients evenly distributed. Mixing time shall be measured
from the time all materials are emptied into the drum (provided all the
water is added before one-fourth the preset mixing time has elapsed) and
continues until the time the discharge chute is opened to deliver the
econocrete.

If mixing in a plant, the mixing time shall not be less than 50 nor
greater than 90 seconds. If mixing in a truck, the mixing time shall not
be less than 70 nor more than 125 truck-drum revolutions at a mixing
speed of not less than 6 nor more than 18 truck-drum revolutions per
minute.

Retempering econocrete by adding water or by other means will not be
permitted, except when econocrete is delivered in truck mixers. With
truck mixers, additional water may be added to the batch materials and
additional mixing performed to allow proper placement of the material,
provided (a) the addition of water is performed within 45 minutes after
the initial mixing operations and (b) the water/cementitious ratio
specified in the mix design is not exceeded.

**306-5.7 HAULING**. The elapsed time from the addition of cementitious
material to the mix until the econocrete is deposited in place at the
work site shall not exceed 45 minutes when the concrete is hauled in
nonagitating trucks, nor 90 minutes when it is hauled in truck mixers or
truck agitators.

**306-5.8 PLACING, CONSOLIDATING, AND FINISHING.** Prior to placement of
the econocrete layer, the prepared underlying course shall be well
moistened with water, without saturating, in order to prevent rapid loss
of moisture from the econocrete. In cold weather, the underlying course
shall be protected so that it will be entirely free of frost when
econocrete is placed.

The Contractor has the option of side- (fixed-) form or slip-form
paving. Under both techniques, the hauled econocrete material shall be
discharged onto the prepared underlying course such that segregation of
the mix is minimized and minimum handling of the mix is needed.
Placement of the econocrete material shall be continuous between
construction joints. Workers shall not be allowed to walk in the freshly
mixed econocrete with boots or shoes coated with earth or debris.

Econocrete shall not be mixed, placed, or finished when the natural
light is insufficient, unless an adequate artificial lighting system is
provided.

**306-5.8.1 Side-Form Construction[.]{.underline}** For side-form
placement, the Contractor shall verify the elevations of the fixed forms
such that the thickness and finished grade of the econocrete layer will
be in accordance with the requirements of the project plans and
specifications. The econocrete shall be spread uniformly between the
forms, immediately after it is placed using a spreading machine.
Necessary hand spreading shall be done with shovels, not rakes.

The spreading shall be followed immediately by thorough consolidation
using vibrating screeds or spud vibrators. Vibrators may be external or
internal type, depending on the thickness of the econocrete layer. The
surface vibrators may be attached to the spreader or they may be mounted
on a separate carriage. They shall not come in contact with the joint,
subgrade, or side forms. When spud vibrators are used, the econocrete
shall be thoroughly consolidated against and along the faces of all
forms and previously placed econocrete. Vibrators shall not be permitted
to come in contact with a joint assembly, the grade, or a side form. In
no case shall the vibrator be operated longer than 20 seconds in any one
location, nor shall the vibrators be used to move the econocrete.

Hand finishing will not be permitted except in areas where the
mechanical finisher cannot operate.

**306-5.8.2 Slip-Form Construction.** For slip-form construction, the
Contractor shall verify the elevations of the guide wires controlling
slip-form pavers such that the thickness and finished grade of the
econocrete will be in accordance with the requirements of the project
plans and specifications. The slip-form paver should spread,
consolidate, and shape the freshly placed econocrete in one complete
pass of the machine. The machine shall vibrate and finish the econocrete
for the full width and depth of the layer.

**306-5.9 Final Finishing**. Final finishing shall be accomplished while
the econocrete is still in the plastic state. Limited surface
refinishing by hand is acceptable to meet the grade and surface
tolerance established in paragraphs 306-6.2.3 and 306-6.2.4, after
strike off and consolidation.

If the overlying layer is to be PCC pavement, the surface of the
econocrete shall not be textured. If the overlying layer is to be HMA
pavement, and if the bond between the HMA layer and the econocrete is
considered important for pavement performance, tining or scarifying the
surface to provide a coarse texture may be permitted.

**306-5.10 JOINTS**. Joints shall be constructed as shown on the plans.

**306-5.10.1 Construction Joints***[.]{.underline}* Locate all
longitudinal and transverse construction joints as shown on the plans.
If longitudinal joints are not shown, locate longitudinal joints within
6 in (152 mm) from planned joints in the PCC to be placed over the
econocrete.

**306-5.10.2 Contraction Joints**. If required by paragraph306-3.1.1or
if shown on the plans, transverse contraction joints shall be
constructed by sawing the hardened econocrete to a depth of at least
one-third the thickness of the econocrete base. These joints shall match
within 3 in (76 mm) the planned joints of the overlying concrete
surface.

\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \*

The Engineer should include a note or detail on the plans when joints
are required due to excessive strength or otherwise.

\* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \*\* \* \* \* \* \* \* \* \* \* \*
\* \* \* \* \* \* \* \* \* \* \* \* \* \*

**306-5.10.3 Concrete Saws.** When sawing of joints are specified, the
Contractor shall provide sawing equipment adequate in number of units
and power to complete the sawing to the required dimensions and at the
required rate. The Contractor shall provide at least one standby saw in
good working order. An ample supply of saw blades shall be maintained at
the site of the work at all times during sawing operations. The
Contractor shall provide adequate artificial lighting facilities for
night sawing. All of this equipment shall be on the job both before and
at all times during econocrete placement.

**306-5.11 CURING**. Immediately after the finishing operations are
complete and within 2 hours of placement of the econocrete, the entire
surface and edges of the newly placed econocrete shall be sprayed
uniformly with white pigmented, liquid membrane forming curing compound.
The layer should be kept moist using a moisture-retaining cover or a
light application of water until the curing material is applied. The
curing compound shall not be applied during rainfall.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> Excessive delays in applying the curing compound can result in
> uncontrolled shrinkage cracking, which can reflect into the overlying
> pavement over time.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

The curing material shall be applied using mechanical sprayers under
pressure at the rate of 1 gal (3.8 L) to not more than 200 ft^2^ (18.6
m^2^). The spraying equipment shall be of the fully atomizing type
equipped with a tank agitator. At the time of use, the compound in the
tank shall be in a thoroughly mixed condition with the pigment uniformly
distributed throughout the vehicle. During application the compound
shall be stirred continuously by mechanical means.

Hand spraying of odd widths or shapes and econocrete surfaces exposed by
the removal of forms is permitted.

Should the film of curing material become damaged from any cause,
including sawing operations, within the required 28-day curing period or
until the overlying course is constructed, the damaged portions shall be
repaired immediately with additional compound or other approved means as
quickly as practical.

Edges of the econocrete layer shall be sprayed with curing compound
immediately following placement with slip-form pavers or when side-forms
are removed.

**306-5.11.1 Curing in Cold Weather**. The econocrete shall be
maintained at a temperature of at least 50°F (10°C) for a period of 72
hours after placing and at a temperature above freezing for the
remainder of the curing time. The Contractor shall be responsible for
the quality and strength of the econocrete placed during cold weather,
and any econocrete injured by frost action shall be removed and replaced
at the Contractor\'s expense.

**306-5.11.2 Curing in Hot Weather.** When econocrete is being placed
and the air temperature may be expected to rise above 90°F (32°C)
shortly after placement, the econocrete layer should be cured as quickly
as possible to allow curing without the formation of excessive shrinkage
cracks.

**306-5.12 PROTECTION**. The Contractor shall protect the pavement and
its appurtenances against both public traffic and traffic caused by the
Contractor's employees and agents. The Engineer shall decide when the
pavement shall be opened to traffic. Traffic shall not be allowed on the
pavement until test specimens molded and cured in accordance with ASTM C
31 have attained a compressive strength of 350 psi (2,413 kPa) when
tested by ASTM C 39. The econocrete surface shall be protected from foot
and vehicular traffic and other sources of abrasion until such a time.
During this time, the econocrete layer shall be protected from injurious
action by sun, rain, flowing water, frost, or mechanical injury. After
this period, construction traffic to place the overlying layers may be
allowed.

**306-5.13 BOND-BREAKER**. When the econocrete is to be placed directly
beneath PCC pavement, a bond-breaker shall be used. The entire surface
of the econoncrete shall be coated with a de-bonding compound applied in
a quality sufficient to prevent bonding of the PCC pavement to the
econocrete. If an impervious membrane or asphalt emulsion is used as a
curing material, additional applications of curing materials may be
required. The Contractor shall be responsible for selecting the
de-bonding compound and determining the necessary application rate. The
de-bonding compound shall be approved by the Engineer prior to being
incorporated into the work. This application shall be made at least 8
hours and not more than 24 hours prior to beginning the placement of the
PCC pavement. The rate of application shall be the same as that
specified for the curing application. After application of the
bond-breaker coat, traffic will be limited to that required for the
placement of the overlying pavement layer.

[]{.mark}

#### MATERIAL ACCEPTANCE

**306-6.1 ACCEPTANCE SAMPLING AND TESTING.** All acceptance sampling and

testing, with the exception of coring for thickness determination,
necessary to determine conformance with the requirements specified in
this section will be performed by the Engineer. The Contractor shall
provide the required econocrete samples during construction for
acceptance testing purposes. The samples shall be taken in the presence
of the Engineer.

The econocrete layer shall be tested for air content, strength,
thickness, grade, and surface tolerance. Sampling and testing for air
shall be as specified in paragraph 306-6.1.1. Sampling and testing for
strength, thickness, grade, and surface tolerance shall be on a lot
basis, with a lot consisting of one of the following:

-   One day's production not to exceed 2,000 yd^2^ (1,675 m^2^).

-   A half day's production, where a day's production is expected to
    consist of between 2,000 and 4,000 yd^2^ (1,675 and 3,350 m^2^).

Each lot will be divided into four equal sublots. In the event that only
three (3) sublots are produced, the three sublots shall constitute a
complete lot. If, only one (1) or two (2) sublots are produced, they
shall be incorporated into the next lot, and the total number of sublots
shall be used in the acceptance plan calculation.

End-of-production sublots (i.e., sublots associated with the final
placement of econocrete for the project and are less than a complete
lot) shall be handled as:

-   Three (3) sublots shall constitute a lot.

-   One (1) or (2) sublots shall be incorporated into the previous lot.

**306-6.1.1 Air Content Testing**. Air content tests shall be performed
on the first three truckloads of econocrete produced at the start of
operations each day and the first three truckloads produced after any
scheduled or non-scheduled shutdown. Additional tests shall be performed
each time a sample is taken for a strength test and when requested by
the Engineer.

Air content tests shall be made in accordance with ASTM C 231. Air
content test results shall be between 4 and 8 percent.

If the first test on a truckload of econocrete is not within the
specification limits, a second test on the same truckload shall be made.
If the second test is within the specification limits, the econocrete
will be accepted with respect to entrained air content. If the second
test is not within the specification limits, the truckload shall be
rejected.

**306-6.1.2 Compressive Strength Testing***.* One sample of freshly
delivered econocrete shall be taken from each sublot for compressive
strength testing. The econocrete shall be sampled in accordance with
ASTM C 172. Sampling locations shall be determined in accordance with
the random sampling procedures contained in ASTM D 3665.

At least two (2) test cylinders shall be made from each sample in
accordance with ASTM C 31. The 7-day compressive strength of each
cylinder shall be determined in accordance with ASTM C 39.

> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
>
> Since the strength level of econocrete at an early age is considerably
> lower than PCC, special care is required in handling test specimens.
>
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*
> \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \* \*

The Contractor shall provide adequate facilities for the initial curing
of cylinders. During the 24 hours after molding, the temperature
immediately adjacent to the specimens must be maintained in the range of
60 to 80°F (16 to 27°C), and loss of moisture from the specimens must be
prevented. The specimens may be stored in tightly constructed wooden
boxes, damp sand pits, temporary buildings at construction sites, under
wet burlap in favorable weather or in heavyweight closed plastic bags,
or use other suitable methods, provided the temperature and moisture
loss requirements are met.

The compressive strength for each sublot shall be computed by averaging
the 7-day compressive strengths of the two test cylinders representing
that sublot. The compressive strength of the lot shall be the average
compressive strength of the individual sublots comprising the lot.

Specimens that are noticeably defective shall not be considered in the
determination of the strength. If the test specimens fail to conform to
the requirements for strength, the Engineer shall request changes in the
econocrete mixture to increase the strength to meet the requirements.

If the maximum 7-day compressive strength values exceed the maximum
strength requirements when evaluated in accordance with paragraph
306-6-2.1, the Contractor shall propose a jointing plan for approval by
the Engineer.

**306-6.1.3 Thickness Testing.** After the econocrete base has cured for
3 days, one (1) 4-in (102-mm) diameter core per sublot shall be obtained
from a random location, as identified using the procedures contained in
ASTM D 3665. The thickness of each sampled core shall be determined
using the caliper measurement procedures provided by ASTM C 174. The
average thickness for the lot shall be determined using the individual
sublot core thicknesses. Acceptance criteria for econocrete thickness
are provided in paragraph 306-6.2.2.

When such measurement is deficient more than ½ in (12.5 mm) and not more
than 1 in (25.4 mm) from the plan thickness, two additional cores shall
be taken at random and used in determining the average thickness for
that lot. The thickness of the cores shall be determined by average
caliper measurement of cores tested in accordance with ASTM C 174.

At all locations where cores have been drilled, the resulting holes
shall be filled with econocrete or non-shrink grout material, as
approved by the Engineer.

**306-6.1.4 Grade Testing.** The elevations of the finished econocrete
shall be surveyed on both sides of the econocrete lane, every 25 ft (7.6
m).

**306-6.1.5 Surface Tolerance Testing.** After the econocrete has
hardened sufficiently, it shall be tested for surface tolerance with a
16-ft (4.9-m) straightedge provided by the Contractor.

**306-6.2 ACCEPTANCE CRITERIA.** Acceptance of econocrete will be based
on compressive strength, thickness, grade, and surface tolerance, as
described in the paragraphs below.

***306-6.2.1 Compressive Strength Requirements*.** The econocrete shall
meet all of the following compressive strength requirements on a lot
basis:

-   The compressive strength of the lot, tested at 7 days, shall be
    greater than 500 psi (3,445 kPa). When a given lot of econocrete
    fails to meet the minimum compressive strength requirements, the
    entire lot shall be replaced at the Contractor's expense.

-   Not more than 20 percent of the individual cylinders in a given lot,
    tested at 7 days, shall have a compressive strength greater than 800
    psi (5,512 kPa). When greater than 20 percent of the individual
    cylinders in a given lot have 7-day compressive strengths in excess
    of 800 psi (5,512 kPa), and transverse joints have not been
    constructed, a bond-breaker shall be used.

**306-6.2.2 Thickness Requirements.** The completed thickness shall be
as shown on the plans. When the average lot thickness is not deficient
by more than ½ in (12.5 mm) from the plan thickness, full payment shall
be made. If the lot average thickness is deficient by more than 1 in
(25.4 mm), it shall be removed and replaced at the Contractor's expense.
When such measurement is deficient more than ½ in (12.5 mm) and not more
than 1 in (25.4 mm) from the plan thickness, one additional core shall
be taken at random from each sublot within the lot. The thickness of
these additional cores shall be determined as indicated in paragraph
304-6.1.2. A new lot average thickness shall be recomputed based on
these additional cores and the original cores taken from each sublot.
When the recomputed average lot thickness is not deficient by more than
½ in (12.5 mm) from the plan thickness, full payment shall be made. If
the average lot thickness is deficient by more than ½ in (12.5 mm) from
the plan thickness, the entire lot shall be removed and replaced at the
Contractor\'s expense or shall be permitted to remain in place at an
adjusted payment of 75 percent of the contract unit price.

When the measured thickness is more than that indicated on the plans, it
will be considered as conforming to the requirements, provided the
surface of the completed econocrete layer is within the established
grade and surface tolerance requirements.

**306-6.2.3 Grade Requirements**. When the completed surface is more
than ½ in (12.5 mm) above the grade shown in the plans, the surface
shall be trimmed at the Contractor's expense using an approved grinding
machine to an elevation that falls within a tolerance of ¼ in (6 mm).
The ground surface shall be sprayed with curing compound at double the
rate specified prior to paving.

**306-6.2.4 Surface Tolerance Requirements.** Surface deviations shall
not exceed ⅜ in (9.5 mm) from a 16-ft (4.9-m) straightedge laid in any
location parallel with or at right angles to the longitudinal axis of
the centerline (includes along all edges of the paving lane). Any high
spots of more than ⅜ in (9.5 mm) in 16 ft (4.9 m) shall be marked and
immediately trimmed with an approved grinding machine. If the overlying
layer is PCC pavement, the ground surface shall be sprayed with a double
application of the curing compound at the specified rate prior to
paving.

#### METHOD OF MEASUREMENT

**306-7.1** The quantity of econocrete to be paid for will be determined
by the number of \[yd^2^ (m^2^)\] of econocrete actually constructed and
accepted by the Engineer as complying with the plans and specifications.

#### BASIS OF PAYMENT

**306-8.1** The accepted quantities of econocrete will be paid for at
the contract unit price per \[yd^2^ (m^2^)\] for econocrete base. The
price and payment shall be full compensation for furnishing and placing
all materials, provided; however, for any pavement found deficient in
thickness as specified in paragraph 306-6.2.2, the reduced unit price
shall be paid.

Payment will be made for econocrete base course\--per \[yd^2^ (m^2^)\].

#### TESTING REQUIREMENTS

ASTM C 31 Making and Curing Concrete Test Specimens in the Field

ASTM C 39 Compressive Strength of Cylindrical Concrete Specimens

ASTM C 136 Sieve or Screen Analysis of Fine and Course Aggregates

ASTM C 172 Sampling Freshly Mixed Concrete

ASTM C 173 Air Content of Freshly Mixed Concrete by the Volumetric
Method

ASTM C 174 Measuring Length of Drilled Concrete Cores

ASTM C 192 Making and Curing Concrete Test Specimens in the Laboratory

ASTM C 231 Air Content of Freshly Mixed Concrete by the Pressure Method

ASTM D 560 Standard Test Methods for Freezing and Thawing Compacted
Soil-Cement Mixtures

ASTM D 3665 Random Sampling of Paving Materials

AASHTO T 26 Quality of Water to be Used in Concrete

#### MATERIAL REQUIREMENTS

ASTM C 33 Specification for Concrete Aggregates

ASTM C 94 Specification for Ready-Mixed Concrete

ASTM C 150 Specification for Portland Cement

ASTM C 260 Specification for Air-Entraining Admixtures for Concrete

ASTM C 309 Specification for Liquid Membrane-Forming Compounds for
Curing Concrete

ASTM C 494 Specification for Chemical Admixtures for Concrete

ASTM C 595 Standard Specification for Blended Hydraulic Cements

ASTM C 618 Specification for Fly Ash and Raw and Calcined Natural
Pozzolans for Use in Portland Cement Concrete

# 

ASTM C 989 Standard Specification for Ground Granulated Blast-Furnace
Slag for Use in Concrete and Mortars

### END P-306