03E02/14/07

S304-03E.doc

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  Use when treating base course aggregate or existing pavement and
  aggregate base.

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Section 304. --- AGGREGATE STABILIZATION

[Delete the Section and substitute the following:]{.underline}

## Section 304. --- AGGREGATE STABILIZATION

Description

**304.01** This work consists of constructing a stabilized aggregate
layer with either , in-place aggregate course, in-place pavement and
base or imported aggregate course. The aggregate layer is stabilized by
incorporating cement or fly ash plus lime, and cement (AFLC).

Imported aggregate grading is designated as shown in Table 703-2.

Material

**304.02** Conform to the following Subsections:

Aggregate 703.05

Blotter 703.13

Chemical admixtures (set-retarding) 711.03

Emulsified asphalt 702.03

Fly ash 725.04

Portland cement 701.01(a)

Lime 725.03

Water 725.01

Construction Requirements

**304.03 Proportioning.** Submit a mix design 30 days before production.

**(a) Cement mixtures.** Design and use a mixture that meets the
requirements of Table 304-1. Design the cement mixture by estimating the
median cement content required for maximum density of the mixture and
select cement contents by mass at 2 percentage points above and 2
percentage points below the estimated median cement content in
accordance with ASTM D 558.

At the 3 cement contents:

**(1)** Determine the 7-day unconfined compressive strength according to
ASTM D 1633, method A.

**(2)** Determine the loss in mass according to ASTM D 559 and ASTM 560.

At the optimum cement content determine the maximum density and optimum
moisture content according to AASHTO T 180 Method D using a minimum of 5
points. The values will be used for in-place density and moisture
content of aggregate or aggregate asphalt mixtures according to
Subsections 304.05 and 304.08.

Table 304-1

Aggregate Cement Mix Design Parameters

+--------------------------------------------------+-------------------+
| **Material or Property**                         | **Requirement**   |
+--------------------------------------------------+-------------------+
| Aggregate                                        | 90 - 96 % ^(1)^   |
+--------------------------------------------------+-------------------+
| Portland cement                                  | 4 - 10 % ^(1)^    |
+--------------------------------------------------+-------------------+
| Loss in mass, ASTM D 559 & D 560 (12 cycles)     | 14% max.          |
|                                                  |                   |
| A-1, A-2-4, A-2-5, & A-3                         | 10% max.          |
|                                                  |                   |
| A-2-6, A-2-7, A-4, & A-5                         | 7% max.           |
|                                                  |                   |
| A-6 & A-7                                        |                   |
+--------------------------------------------------+-------------------+
| 7-day unconfined compressive strength,           | 300 - 700 psi     |
|                                                  |                   |
| ASTM D-1633, method A ^(2)^                      | 250 psi min.      |
|                                                  |                   |
| Average compressive strength:                    |                   |
|                                                  |                   |
| Single compressive strength:                     |                   |
+--------------------------------------------------+-------------------+

> ^(1)^ By mass of total dry mix.
>
> ^(2)^ Prepared per ASTM D 558

**(b) AFLC mixtures.** Design a mixture that meets the requirements of
Table 304-2. Determine the optimum fly ash plus lime and cement content
according to ASTM C 593, Section 10 using several mixtures with varying
fly ash plus lime and cement contents. The peak of the density fly ash
plus lime and cement content curve is the optimum fly ash plus lime and
cement content.

Determine the lime and cement, fly ash ratio according to ASTM C 593,
Sections 10 and 11 using a series of mixtures at the optimum fly ash
plus lime and cement content and varying lime and cement, fly ash ratio.
Use a mixture with a fly ash plus lime and cement content that exceeds
the optimum fly ash plus lime and cement content by 0.5 percent.

For in-place moisture density control of aggregate or aggregate asphalt
mixtures use a minimum of 5 points to determine the maximum density and
optimum moisture content of the mixture according to AASHTO T 180 Method
D.

Table 304-2

AFLC Mix Design Parameters

+--------------------------------------------------+-------------------+
| **Material or Property**                         | **Requirement**   |
+--------------------------------------------------+-------------------+
| Aggregate                                        | 75 - 92 %^(1)^    |
+--------------------------------------------------+-------------------+
| Fly ash                                          | 6 - 20 %^(1)^     |
+--------------------------------------------------+-------------------+
| Lime and Portland cement                         | 2 - 5 %^(1)^      |
+--------------------------------------------------+-------------------+
| 7-day unconfined compressive strength,           | 300 - 700 psi     |
|                                                  |                   |
| ASTM C 593                                       | 250 psi min.      |
|                                                  |                   |
| Average compressive strength:                    |                   |
|                                                  |                   |
| Single compressive strength:                     |                   |
+--------------------------------------------------+-------------------+

> ^(1)^ By mass of total dry mix.

**(c) Job-mix formula.**

**(1)** Submit the following for each job-mix formula:

*(a)* Source of each component;

*(b)* Results of applicable tests; and

*(c)* Target values for:

*(1)* Each aggregate sieve size specified as applicable; and

*(2)* Stabilizing agent(s).

**(2)** At the request of the CO, submit the following:

*(a)* 200-pound sample of aggregate;

*(b)* 50-pound sample of fly ash;

*(c)* 25-pound sample of lime;

*(d)* 25-pound sample of Portland cement; and

*(e)* 5-pound sample of retarder or other admixtures.

Furnish a new mix design if there is a change in a material source.
Begin production only after the mix design is approved.

**304.04 General.** Store stabilizing agents and admixtures in closed,
weatherproof containers. Do not construct the stabilized aggregate layer
when the underlying surface is frozen, muddy, or when it is raining or
snowing. Do not begin application or mixing operations when the
atmospheric temperature is expected to fall below 40 ºF within 48 hours.

**(a) Imported aggregate course.** Prepare the underlying surface
according to Section 204, Subsection 303.05, or Subsection 303.06, as
applicable.

**(b) In-place aggregate course.** Recondition the aggregate according
to Subsection 303.06 to meet the gradation shown in Table 304-3. Shape
the scarified aggregate into a windrow or blanket that is suitable for
applying stabilizing agents.

**(c) In-place pavement and base**. Pulverize the existing pavement and
underlying base to the gradation shown in Table 304-3 to the depths
specified in the plans. Mix the in-situ material with stabilizing agent
and water to produce a durable base.

Table 304-3

In-Place Aggregate or

In-Place Pavement and Base Gradation

  --------------------------------------------- -------------------------
  **Sieve Designation**                         **Percent Passing**

  1 ½ inch                                      100

  ¾ inch                                        85 -- 100

  No. 4                                         55
  --------------------------------------------- -------------------------

**304.05 Applying stabilizing agents.**

**(a) Imported aggregate course.** Equip the mixer with batching or
metering devices for proportioning the components either by mass or
volume. Maintain the accuracy of the amounts of aggregate, chemical
additives, and water (based on the total dry mass) within the following
tolerances:

Aggregate ±2.0% by mass

Fly ash ±1.5% by mass

Lime and cement ±0.5% by mass

Retarder or other additive ±2.0% by mass

Water ±2.0% by mass

In aggregate cement mixtures, a retarder may be used to slow initial set
for a maximum of 2 hours. Suspend the retarder in water and then
uniformly add it to the mixture.

**(b) In-place aggregate course or In-place pavement and base.** Do not
apply stabilizing agents when conditions allow excessive loss to washing
or blowing. Apply stabilizing agents at the required rates by one of the
following methods:

**(1) Dry method.** Uniformly apply the stabilizing agents with an
approved spreader. Apply water using approved methods to obtain the
proper moisture content for mixing and compaction according to
Subsection 304.08.

**(2) Slurry method.** Mix stabilizing agents with water and apply as a
thin water suspension or slurry using either trucks with approved
distributors or rotary mixers. Equip the distributor truck or rotary
mixer tank with an agitator to keep the stabilizing agents suspended in
water to obtain the moisture and stabilizing agents content for mixing
and compacting according to Subsection 304.08.

**304.06 Adding and Mixing of components.** The amount of cement or AFLC
to be added will be based on the percent of the approved mix design. Mix
the components with suitable equipment until all additives are
distributed uniformly within the aggregate to create a homogeneous
mixture. When a central plant is used, transport the mixture in vehicles
that maintain moisture content, prevent segregation and loss of the fine
material.

**(a) Cement mixtures.** Add water and thoroughly mix to adjust the
moisture content of the mixture as determined from the mix design and
approved by the CO. Complete the mixing within 2 hours of cement
application.

**(b) AFLC mixtures.** Add water and thoroughly mix to adjust the
moisture content of the mixture to optimum moisture content plus any
necessary hydration moisture as determined from the mix design and
approved by the CO. Complete the mixing within 6 hours of additive
application. Cure the mixture for 2 to 4 days by keeping it moist.

**304.07 Production Start-Up Procedures.** At least two weeks prior to
the start of stabilizing operations, arrange for a pre-production
conference. Coordinate attendance with CO and any application
subcontractors. Discuss and submit the following:

**(a)** Discuss approved mix design and proposed schedule of stabilizing
operations.

**(b)** List of all equipment (excavation-compaction equipment, laydown,
haul, etc., and personnel used in the production and construction of the
work.

**(c)** Proposed Traffic Control Plan for moving operations, and the
proposed method of dealing with emergencies. Show in detail how traffic
will be maintained through the project in the event of equipment
breakdown, sudden weather changes, or other unexpected events. Include
in the plan how sufficient roadway width for safe passage of traveling
public will be maintained.

**(d)** Discuss Section 153, Contractor Quality Control, and minimum
frequency schedule for process control sampling and testing and Section
154, Contractor Sampling and Testing.

**(e)** Discuss construction of test strip.

**(f)** Discuss Subsections 106.02, 106.03, and 106.04 and 304.12,
Acceptance.

**(g)** Proposed plan for maintaining the finished surface before
placement of next layer.

On the first day of production, stabilize a 1000-foot long test strip,
one-lane wide, at the designated thickness and mix design proportions.
Construct the test strip on the project at an approved location.

Construct the test strip using construction procedures intended for the
entire project. Cease production after construction of the test strip
until the stabilized base course and the test strip are evaluated by the
contractor's laboratory and accepted by the CO.

> **(1) Mixture properties.** Take at least three control strip samples
> and evaluate according to Table 304-4. The mix is acceptable if all
> test results are above the minimum specifications shown in Subsection
> 304.03 and within the design tolerances of Subsection 304.05.
>
> **(2) Compaction.** Take nuclear density readings behind each roller
> pass to determine the roller pattern necessary to achieve
> specifications without damaging the mix.

Repeat the test strip process until an acceptable test strip is
produced. See Subsection 106.01 for the disposition of material in
unacceptable test strips. Accepted test strips may remain in place and
will be accepted and measured as a part of the stabilized base course.
Tests results used for the test strip will not be included in the
evaluation for payment according to Subsection 106.04. When a test strip
is accepted, full production may begin.

Use these start-up procedures when a change in construction procedures
occurs or when resuming production after a termination of production due
to unsatisfactory quality according to Subsection 106.04.

**304.08 Placing, Compacting, and Finishing.** While placing and
spreading the mixture, maintain the moisture content within 2 percent of
optimum. Do not leave uncompacted aggregate cement mixtures undisturbed
for more than 30 minutes, and complete their compaction and finishing
within 1 hour from the time water is added. Additional time may be
permitted if a retarder is used.

Compact the mixture to at least 95 percent of the maximum density as
determined by AASHTO T-180, Method D. Determine the in-place density and
moisture content according to AASHTO T 310 or other approved test
procedures.

Finish the aggregate course according to Subsection 301.06 to produce a
surface that is smooth, dense, and free of compaction planes, ridges, or
loose material.

**304.09 Construction Joints.** For AFLC mixtures, tie each day's work
into the completed work of the previous day by remixing approximately 2
feet of the completed course before processing additional sections. Add
50 percent of the original amount of lime or fly ash to the remixed
material.

For aggregate cement mixtures or when an AFLC mixture remains
undisturbed for more than 24 hours, make a transverse construction joint
by cutting back into the completed work to form an approximately
vertical face.

**304.10 Curing and traffic.**

**(a) Curing**. Protect completed portions that are traveled on by
equipment used in constructing an adjoining section in such a manner as
to prevent equipment from marring or damaging completed work. If the
stabilized aggregate looses stability, density, or finish, reprocess,
re-compact, and add additives as necessary to restore the strength of
the damaged material. After completion of final finishing protect the
surface by applying a continuous mist for a period of 7 days with a
fog-type water spray that will not erode the surface. Place the next
layer within 7 days of finishing the aggregate stabilization. This may
be deferred up to 21 days by sealing the surface with rapid-setting
emulsified asphalt or cutback asphalt. Apply undiluted CRS-2 emulsified
asphalt or RS-2 cutback asphalt at a rate of 0.2 gallons per square yard
according to Section 409. Provide a continuous film over the surface.
Should it be necessary for construction equipment or other traffic to
use the bituminous-covered surface before the materials has dried
sufficiently to prevent pickup, sufficient blotter will be applied.
Furnish and apply blotter according to Section 411. Reapply the asphalt
seal where the continuous film is damaged as directed by the CO.

**(b) Traffic.** Completed portions may be opened immediately to
low-speed local traffic and to construction equipment provided the
moisture curing operations are not impaired and provided the mixtures is
sufficiently stable to withstand marring or permanent deformation. After
7-day moisture curing period the treated area can be opened to all
traffic provided the treated area has hardened sufficiently to prevent
marring or permanent deformation.

**304.11 Acceptance.** See Table 304-4 for sampling and testing
requirements.

Material for blotter, chemical admixtures, fly ash, lime, hydraulic
cement, and water will be evaluated under Subsections 106.02 and 106.03.
Emulsified asphalt will be evaluated under Subsections 106.03 and
702.09.

New imported aggregate will be evaluated for gradation according to
Subsection 301.08(a).

Stabilized imported and in-place aggregate courses will be evaluated
under Subsections 106.02 and 106.04.

Reconditioning of the aggregate course for in-place aggregate will be
evaluated under Section 303.

Preparation of the surface on which the treated imported aggregate
course is placed will be evaluated under Sections 204 or 303.

Emulsified asphalt seal will be evaluated under Section 409.

Blotter will be evaluated under Section 411.

Measurement

**304.12** Measure the Section 304 items listed in the bid schedule
according to Subsection 109.02 and the following as applicable.

Measure square yard width horizontally to include the top of aggregate
width including designed widening. Measure the square yard length along
the centerline of the roadway. Measure this work only one time,
regardless of the number of passes required to meet the grading
specified and achieve uniform mixture.

Measure Cement, fly ash, and lime by the ton.

Measure emulsified asphalt under Section 409.

Measure blotter under Section 411.

Water will not be measured for payment.

Measure removal and disposal of unsuitable materials under Section 203
or 204.

Payment

**304.13** The accepted quantities measured as provided in Subsection
109.02, will be paid at the contract price per unit of measurement for
the Section 304 pay items listed in the bid schedule. Payment will be
full compensation for the work prescribed in this Section. See
Subsection 109.05.

**Table 304-4**

Sampling, Testing and Requirements

+--------+---------+-------+----+--------+------+------+----+------+
| **Ma   | **Type  | **C   | ** | **Test | **   | **P  | *  | **R  |
| terial | of      | harac | Ca | M      | Samp | oint | *S | epor |
| or     | Accep   | teris | te | ethods | ling | of   | pl | ting |
| Prop   | tance** | tic** | go | Spec   | Fre  | Sa   | it | Ti   |
| erty** |         |       | ry | ificat | quen | mpli | Sa | me** |
|        | **      |       | ** | ions** | cy** | ng** | mp |      |
|        | (subsec |       |    |        |      |      | le |      |
|        | tion)** |       |    |        |      |      | ** |      |
+--------+---------+-------+----+--------+------+------+----+------+
| Cement | M       | C     | \  | ASTM D | 1    | P    | Ye | Be   |
| Mi     | easured | ompre | -\ | 1633,  | for  | roce | s, | fore |
| xtures | and     | ssive | -- | method | each | ssed | wh | u    |
|        | tested  | str   |    | A      | mix  | mate | en | sing |
| Mix    |         | ength |    |        | ture | rial | r  | in   |
| design | for     |       |    |        | or   | be   | eq | work |
| (      | conf    |       |    |        | ch   | fore | ue |      |
| 304.03 | ormance |       |    |        | ange | i    | st |      |
| and    |         |       |    |        | in   | ncor | ed |      |
| Table  | (       |       |    |        | mate | pora |    |      |
| 304-2) | 106.04) |       |    |        | rial | ting |    |      |
|        |         |       |    |        |      | in   |    |      |
|        |         |       |    |        |      | work |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | Moist |    | AASHTO |      |      |    |      |
|        |         | ure - |    | T 180, |      |      |    |      |
|        |         | de    |    | method |      |      |    |      |
|        |         | nsity |    | D      |      |      |    |      |
|        |         |       |    | ^(1)^  |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | Loss  |    | ASTM D |      |      |    |      |
|        |         | in    |    | 559    |      |      |    |      |
|        |         | mass  |    | and D  |      |      |    |      |
|        |         |       |    | 560    |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
| Aggr   | M       | C     | \  | ASTM C | 1    | P    | Ye | Be   |
| egate, | easured | ompre | -\ | 593    | for  | roce | s, | fore |
| fly    | and     | ssive | -- |        | each | ssed | wh | u    |
| ash.   | tested  | str   |    |        | mix  | mate | en | sing |
| Lime,  |         | ength |    |        | ture | rial | r  | in   |
| and    | for     |       |    |        | or   | be   | eq | work |
| cement | conf    |       |    |        | ch   | fore | ue |      |
| (AFLC) | ormance |       |    |        | ange | i    | st |      |
|        |         |       |    |        | in   | ncor | ed |      |
| Mix    | (       |       |    |        | mate | pora |    |      |
| design | 106.04) |       |    |        | rial | ting |    |      |
| (      |         |       |    |        |      | in   |    |      |
| 304.03 |         |       |    |        |      | work |    |      |
| and    |         |       |    |        |      |      |    |      |
| Table  |         |       |    |        |      |      |    |      |
| 304-3) |         |       |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | Moist |    | AASHTO |      |      |    |      |
|        |         | ure - |    | T 180, |      |      |    |      |
|        |         | de    |    | method |      |      |    |      |
|        |         | nsity |    | D      |      |      |    |      |
|        |         |       |    | ^(1)^  |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
| Im     | Stat    | Grad  |    | AASHTO | 1    | P    | Ye | 4    |
| ported | istical | ation |    | T 27 & | per  | roce | s, | h    |
| agg    |         |       |    | T 11   | 1000 | ssed | wh | ours |
| regate | (       |       |    |        | tons | mate | en |      |
|        | 106.05) |       |    |        |      | rial | r  |      |
| (7     |         |       |    |        |      | be   | eq |      |
| 03.05) |         |       |    |        |      | fore | ue |      |
|        |         |       |    |        |      | i    | st |      |
|        |         |       |    |        |      | ncor | ed |      |
|        |         |       |    |        |      | pora |    |      |
|        |         |       |    |        |      | ting |    |      |
|        |         |       |    |        |      | in   |    |      |
|        |         |       |    |        |      | work |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | ⅜     | I  |        |      |      |    |      |
|        |         | inch  |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | No. 4 | I  |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | No.   | I  |        |      |      |    |      |
|        |         | 200   |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | Other | II |        |      |      |    |      |
|        |         | spec  |    |        |      |      |    |      |
|        |         | ified |    |        |      |      |    |      |
|        |         | s     |    |        |      |      |    |      |
|        |         | ieves |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        | M       | L     | \  | AASHTO | 1    | P    | \  |      |
|        | easured | iquid | -\ | T 89   | per  | roce | -\ |      |
|        | and     | Limit | -- |        | 3000 | ssed | -- |      |
|        | tested  |       |    |        | tons | mate |    |      |
|        |         |       |    |        |      | rial |    |      |
|        | for     |       |    |        |      | be   |    |      |
|        | conf    |       |    |        |      | fore |    |      |
|        | ormance |       |    |        |      | i    |    |      |
|        |         |       |    |        |      | ncor |    |      |
|        | (       |       |    |        |      | pora |    |      |
|        | 106.04) |       |    |        |      | ting |    |      |
|        |         |       |    |        |      | in   |    |      |
|        |         |       |    |        |      | work |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
| Stab   | M       | Grad  | \  | AASHTO | 1    | mate | Ye | 4    |
| ilized | easured | ation | -\ | T 27 & | per  | rial | s, | h    |
| M      | and     |       | -- | T 11   | 500  | be   | wh | ours |
| ixture | tested  |       |    |        | tons | fore | en |      |
|        |         |       |    |        | or   | i    | r  |      |
| (produ | for     |       |    |        | 3000 | ncor | eq |      |
| ction) | conf    |       |    |        | y    | pora | ue |      |
|        | ormance |       |    |        | d^2^ | ting | st |      |
|        |         |       |    |        |      | in   | ed |      |
|        | (       |       |    |        |      | work |    |      |
|        | 106.04) |       |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+
|        |         | In-   |    | AASHTO |      | C    | \  |      |
|        |         | place |    | T 310  |      | ompa | -\ |      |
|        |         | moi   |    | or     |      | cted | -- |      |
|        |         | sture |    | other  |      | mate |    |      |
|        |         | co    |    | ap     |      | rial |    |      |
|        |         | ntent |    | proved |      | "    |    |      |
|        |         | and   |    | proc   |      |      |    |      |
|        |         | de    |    | edures |      |      |    |      |
|        |         | nsity |    |        |      |      |    |      |
+--------+---------+-------+----+--------+------+------+----+------+

> ^(1)^ Minimum 5 points per proctor.