### **ITEM P-219 RECYCLED CONCRETE** 

### **AGGREGATE BASE COURSE**

DESCRIPTION

**219 -1.1** This item consists of a base course composed of recycled
concrete aggregate, crushed to meet a particular gradation, constructed
on a prepared course in accordance with these specifications and in
conformity to the dimensions and typical cross sections shown on the
plans.

### MATERIALS

**219-2.1 AGGREGATE.** Recycled concrete aggregate shall consist of
Portland cement concrete or other concrete containing pozzolanic binder
material. The recycled concrete material shall be free of reinforcing
steel, expansion material. Asphalt concrete overlays shall be removed
from the PCC surface prior to pavement removal and crushing. Also,
full-slab asphalt concrete panels (used as a replacement for a removed
PCC slab) shall be removed. An incidental amount of recycled asphalt
concrete pavement and other foreign material may be present in the
recycled concrete aggregate.

Recycled concrete aggregate for base course shall consist of at least 90
percent, by weight, Portland cement concrete, with the following
materials making up the remaining 10 percent:

Wood - 0.1 percent maximum

Brick, mica, schist, or other friable materials - 4 percent maximum

Asphalt concrete -- 10 percent maximum

Virgin aggregates may be added to meet the 90 percent minimum concrete
requirement

The percentage of wood, brick, mica, schist, other friable materials,
and asphalt concrete shall be determined by weighing that material
retained on the No. 4 sieve, and dividing by the total weight of
recycled concrete aggregate material retained on the No. 4 sieve.

Fine aggregate passing the No.4 (4.75-mm) sieve shall consist of fines
from the operation of crushing the recycled concrete aggregate. If
necessary, fine aggregate may be added to produce the correct gradation.
The fine aggregate shall be produced by crushing stone, gravel, slag, or
recycled concrete that meet the requirements for wear and soundness
specified for coarse aggregate.

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**To the extent possible, recycled concrete aggregate should be produced
from distress-free (material related) concrete. Published literature and
limited laboratory testing have indicated that alkali-silica reactivity
(ASR) is not a concern for crushed aggregate base course. The pavement
designer should exercise due care in evaluating site conditions and
other factors to ensure the proper use of ASR prone PCC.**

**The engineer shall gather and analyze available information on the
history and performance of the ASR-distressed PCC to be used to
manufacture base material. The results of this investigation will
justify why this material will provide an acceptable level of safety,
economy, and durability. The designer is also advised to consult with
experts (geologists, concrete petrographers, materials engineers, etc.)
on the degree of reactivity of aggregates from the source(s) used to
construct the original PCC. All information including test results and
experts consulted should be documented in the pavement design report.**

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**Recycled concrete aggregate shall not be used in locations with high
sulfate content soils (no more than 1 percent).**

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The amount of flat and elongated particles in recycled concrete
aggregate shall not exceed 20 percent for the fraction retained on the
0.5 inch (13 mm) sieve nor 20 percent for the fraction passing the 0.5
inch (13 mm) sieve when tested in accordance with ASTM D 4791. A flat
particle is one having a ratio of width to thickness greater than 3; an
elongated particle is one having a ratio of length to width greater than
3.

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**Recycled concrete aggregate shape depends on the characteristics of
the recycled concrete, plant type, and plant operation speed. A number
of trial batches may have to be produced before crushed recycled
concrete aggregate meeting the shape and gradation requirements is
produced.**

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The percentage of wear shall not be greater than 45 percent when tested
in accordance with ASTM C 131. The sodium sulfate soundness test (ASTM C
88) requirement is waived for recycled concrete aggregate.

The fraction passing the No. 40 (0.42-mm) sieve shall have a liquid
limit no greater than 25 and a plasticity index of not more than 4 when
tested in accordance with ASTM D 4318. The fine aggregate shall have a
minimum sand equivalent value of 35 when tested in accordance with ASTM
D 2419.

**a. Sampling and Testing.** Recycled concrete aggregate samples for
preliminary testing shall be furnished by the Contractor prior to the
start of base construction. All tests for initial aggregate submittals
necessary to determine compliance with the specification requirements
will be made by the Engineer at no expense to the Contractor.

Samples of recycled concrete aggregate shall be furnished by the
Contractor at the start of production and at intervals during
production. The sampling points and intervals will be designated by the
Engineer. The samples will be the basis of approval of specific lots of
recycled concrete aggregate for the quality requirements.

Samples of recycled concrete aggregate to check gradation shall be taken
at least once daily. Sampling shall be in accordance with ASTM D 75, and
testing shall be in accordance with ASTM C 136 and C 117.

**b. Gradation Requirements.** The gradation (job mix) of the final
mixture shall fall within the design range indicated in Table 1, when
tested in accordance with ASTM C 117 and C 136. The final gradation
shall be continuously graded from coarse to fine and shall not vary from
the low limit on one sieve to the high limit on an adjacent sieve or
vice versa.

+----------------------------+--------------------+--------------------+
| **Table 1. Requirements    |                    |                    |
| for gradation of recycled  |                    |                    |
| concrete aggregate.**      |                    |                    |
+----------------------------+--------------------+--------------------+
| Sieve Size                 | Percentage by      | Job Mix Tolerances |
|                            | Weight             |                    |
|                            |                    | Percent            |
|                            | Passing Sieves     |                    |
+----------------------------+--------------------+--------------------+
| 2 in (50.8 mm)             | 100                | \--                |
+----------------------------+--------------------+--------------------+
| 1-1/2 (37.5 mm)            | 95 - 100           | +/- 5              |
+----------------------------+--------------------+--------------------+
| 1 in (25.0 mm)             | 70 - 95            | +/- 8              |
+----------------------------+--------------------+--------------------+
| 3/4 in (19.0 mm)           | 55 - 85            | +/- 8              |
+----------------------------+--------------------+--------------------+
| No.4 (4.75 mm)             | 30 - 60            | +/- 8              |
+----------------------------+--------------------+--------------------+
| No. 30 (0.60 mm)           | 12 - 30            | +/- 5              |
+----------------------------+--------------------+--------------------+
| No. 200 (0.075 mm)         | 0 - 5              | +/- 3              |
+----------------------------+--------------------+--------------------+

The job mix tolerances in Table 1 shall be applied to the job mix
gradation to establish a job control gradation band. The full tolerance
still will apply if application of the tolerances results in a job
control gradation band outside the design range.

### EQUIPMENT

**219-3.1 GENERAL.** All equipment necessary to mix, transport, place,
compact, and finish the recycled concrete aggregate base course shall be
furnished by the Contractor. The Contractor shall provide written
certification to the Engineer that all equipment meets the requirements
for this section. The equipment shall be inspected by the Engineer at
the job site prior to the start of I construction operations.

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**219-3.2 MIXING EQUIPMENT.** Base course shall be thoroughly mixed in a
plant suitable for recycled concrete aggregate. The mixer shall be a
batch or continuous-flow type and shall be equipped with calibrated
metering and feeding device that introduce the aggregate and water into
the mixer in specified quantities. If necessary, a screening device
shall be installed to remove oversized material greater than 2 in (50
mm) from the recycled concrete aggregate feed.

Free access to the plant shall be provided to the Engineer at all times
for inspection of the plant\'s equipment and operation and for sampling
the mixed recycled concrete aggregate

materials.

**219-3.3 HAULING EQUIPMENT.** The mixed recycled concrete aggregate
base course shall be transported from the plant to the job site in
hauling equipment having beds that are smooth, clean, and tight. Truck
bed covers shall be provided and used to protect the mixed recycled
concrete aggregate base course from rain during transport.

**219-3.4 PLACING EQUIPMENT.** Recycled concrete aggregate shall be
placed using a mechanical spreader or machine capable of receiving,
spreading, and shaping the material without segregation into uniform
layer or lift. The placing equipment shall be equipped with a strike off
plate that can be adjusted to the layer thickness. \[**The placing
equipment shall have two end gates or cut off plates, so that the
recycled concrete aggregate may be spread up to a lane width.\]**

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**The Engineer may add additional equipment requirements.**

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**219-3.5 COMPACTION EQUIPMENT.** Recycled concrete aggregate base
course compaction shall be accomplished using one or a combination of
the following pieces of equipment:

Steel-wheeled roller,

Vibratory roller,

Pneumatic-tire roller,

Hand-operated power tampers (for areas inaccessible to rollers)

**219-3.6 FINISHING EQUIPMENT.** Trimming of the compacted recycled
concrete aggregate to meet surface requirements shall be accomplished
using a self-propelled grader or trimming machine, with a mold board
cutting edge of 12 ft (3.7 m) minimum width automatically controlled by
sensors in conjunction with an independent grade control from a taut
string line. String line will be required on both sides of the sensor
controls for all lanes.

### CONSTRUCTION METHODS

**219-4.1 WEATHER LIMITATIONS.** Construction is allowed only when the
atmospheric temperature is at or above 35 °F (2 °C). When the
temperature falls below 35°F (2 °C), the contractor shall protect all
completed areas against detrimental effects of freezing. Areas damaged
by freezing, rainfall, or other weather conditions shall be corrected.

**219-4.2 PREPARING UNDERLYING COURSE.** The underlying course shall be
checked by the Engineer before placing and spreading operations are
started. Any ruts or soft yielding places caused by improper drainage
conditions, hauling, or any other cause shall be corrected at the
Contractor\'s expense before the base course is placed thereon. Material
shall not be placed on frozen material.

To protect the existing layers and to ensure proper drainage, the
spreading of the recycled concrete aggregate base course shall begin
along the centerline of the pavement on a crowned section or on the
greatest contour elevation of a pavement with a variable uniform cross
slope.

**219-4.3 GRADE CONTROL.** Grade control between the edges of the
recycled concrete aggregate base course shall be accomplished by grade
stakes, steel pins, or forms placed in lanes parallel to the centerline
and at intervals of 50 ft (15 m) or less on the longitudinal grade and
25 ft (7.5 m) or less on the transverse grade.

**219-4.4 MIXING.** The recycled concrete shall be uniformly blended
during crushing operations and mixed with water in a mixing plant
suitable for recycled concrete aggregate. The plant shall blend and mix
the materials to meet the specifications and to secure the proper
moisture content for compaction.

**219-4.5 PLACING.** The recycled concrete aggregate base material shall
be placed on the moistened subgrade or base in layers of uniform
thickness with an approved mechanical spreader.

The maximum depth of a compacted layer shall be 6 inches (150 mm). If
the total depth of the compacted material is more than 6 inches (150
mm), it shall be constructed in two or more layers. In multi-layer
construction, the material shall be placed in approximately equal-depth
layers.

The previously constructed layer shall be cleaned of loose and foreign
material prior to placing the next layer. The surface of the compacted
material shall be kept moist until covered with the next layer.

Adjustments in placing procedures or equipment shall be made to obtain
grades, to minimize segregation grading, to adjust the water content,
and to ensure an acceptable recycled concrete aggregate base course.

**219-4.6. EDGES OF BASE COURSE.** The recycled concrete aggregate shall
be placed so that the completed section will wider, on all sides, than
the next layer that will be placed above it, as shown on the plans.
Approved fill material shall be placed along the free edges of the
recycled concrete aggregate in sufficient quantities to compact to the
thickness of the course being constructed, or to the thickness of each
layer in a .multiple course, allowing in each operation at least a 2-ft
(0.6-m) width of this material to be rolled and compacted simultaneously
with rolling and compacting of each layer of base course. If this base
course material is to be placed adjacent to another pavement section,
then the layers for both of these sections shall be placed and compacted
along the edge at the same time.

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**The Engineer shall show the added width required on the plans,
(generally 1-3' but no more than 5'.**

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**219-4.7 COMPACTION.** Immediately upon completion of the spreading
operations, the recycled concrete aggregate shall be compacted. The
number, type, and weight of rollers shall be sufficient to compact the
material to the required density.

Each layer of the recycled concrete aggregate base course shall be
compacted to the required density using the compaction equipment. The
moisture content of the material during placing operations shall not be
below, nor more than 1-1/2 percentage points above, the optimum moisture
content as determined by ASTM \[ \].

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The Engineer shall specify ASTM D 698 for areas designated for aircraft
with gross weights .of 60,000 pounds (27,200 kg) or less and ASTM D 1557
for areas designated for aircraft with gross weights greater than 60,000
pounds (27 200 kg).

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The compaction shall continue until each layer has a degree of
compaction that is at least 100 percent of the laboratory maximum
density through the full depth of the layer. The contractor shall make
adjustments in compacting or finishing techniques to obtain true grades,
to minimize segregation and degradation, to reduce or increase water
content and to ensure a satisfactory base course. Any materials found to
be unsatisfactory shall be removed and replaced with satisfactory
material or reworked, so that the requirements of this specification are
met.

**219-4.8 ACCEPTANCE SAMPLING AND TESTING FOR DENSITY.** Recycled
concrete aggregate shall be accepted for gradation and density on a lot
basis. A lot will consist of one day\'s production where it is not
expected to exceed 2,400 square yards (2,000 square meters) per lift. A
lot will consist of one-half day\'s production, where a day\'s
production is expected to consist of between 2,400 and 4,800 square
yards (2,000 and 4,000 square meters) per lift.

Each lot shall be divided into two equal sublots. One gradation and
density test shall be made for each sublot. Sampling locations will be
determined on a random basis in accordance with statistical procedures
contained in ASTM D 3665.

Each lot will be accepted for gradation when it falls within the limits
and tolerances shown in Table 1 when tested in accordance with ASTM C117
and C 131. If the proper gradation is not attained the gradation test
will be repeated. The entire lot shall be rejected and replaced by the
Contractor at the Contractor\'s expense.

Each lot will be accepted for density when the field density is at least
100 percent of the maximum density of laboratory specimens prepared from
samples of the base course material delivered to the job site. The
specimens shall be compacted and tested in accordance with ASTM \[ \].
The in-place field density shall be determined in accordance with ASTM D
1556 or D 2167. If the specified density is not attained, the entire lot
shall be reworked and two additional random tests made. This procedure
shall be followed until the specified density is reached.

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**The Engineer shall specify ASTM D 698 for areas designated for
aircraft with gross weights of 60,000 pounds (27 200 kg) or less and
ASTM D 1557 for areas designated for aircraft with gross weights greater
than 60,000 pounds (27 200 kg).**

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In lieu of ASTM D 1556 or D 2167 method of field density determination,
acceptance testing may be accomplished using a nuclear gage in
accordance with ASTM D 2922. The gage should be field calibrated in
accordance with paragraph 4 of ASTM D 2922. Calibration tests shall be
conducted on the first lot of material placed that meets the density
requirements.

Use of ASTM D 2922 results in a wet unit weight, and when using this
method, ASTM D 3017 shall be used to determine the moisture content of
the material. The calibration curve furnished with the moisture gages
shall be checked as described in paragraph 7 of ASTM D 3017. The
calibration checks of both the density and moisture gages shall be made
at the beginning of a job and at regular intervals.

If a nuclear gage is used for density determination, two random
measurements shall be made for each sublot.

**219-4.9 FINISHING.** The surface of the recycled concrete aggregate
base course shall be finished by equipment designed for this purpose.

In no case will thin layers of material be added to the top of base
course to meet grade. If the elevation of the layer is 1/2 inch (12 mm)
or more below grade, the layer shall be scarified to a depth of at least
3 inches (75 mm), new material added, and the layer shall be
recompacted. If the finished surface is above plan grade, it shall be
cut back to grade and rerolled.

Should the surface become rough, corrugated, uneven in texture, or
traffic marked prior to completion, the unsatisfactory portion shall be
scarified, and recompacted or replaced at Contractor\'s expense.

**219-4.10 SURFACE TOLERANCES.** The finished surface shall not vary
more than 3/8 inch (9 mm) when tested with a 16-ft (4.8-m) straightedge
applied parallel with or at right angles to the centerline. The
Contractor shall correct any deviation in excess of this amount, at the
Contractor\'s expense.

**219-4.11 THICKNESS CONTROL.** The completed thickness of the base
course shall be within 0.5 inch (13 mm) of the design thickness. Four
determinations of thickness shall be made for each lot of material
placed. Each lot shall be divided into four equal sublots. One test
shall be made for each sublot. Sampling locations will be determined on
a random basis in accordance with procedures contained in ASTM D 3665.
Where the thickness is deficient by more than 0.5 inch (13 mm), the
Contractor shall correct such areas at no additional cost by excavating
to the required depth and replacing with new material. Additional test
holes may be required to identify the limits of deficient areas.

**219-4.12 TRAFFIC.** Equipment used in construction may be routed over
completed portions of the base course, provided no damage results and
provided that the equipment is distributed evenly over the full width of
the base course to avoid rutting or uneven

compaction.

**219-4.13 MAINTENANCE.** The base course shall be maintained until the
base course is completed and accepted. Maintenance will include
immediate repairs to any defects and shall be repeated as often as
necessary to keep the completed work intact. Any area of the recycled
concrete aggregate base course that is damaged shall be reworked as
necessary .

### METHOD OF MEASUREMENT

**219-5.1** The quantity of recycled concrete aggregate base course to
be paid will be determined by measurement of the number of square yards
(square meters) of material actually constructed and accepted as
complying with the plans and specifications.

### BASIS OF PAYMENT

**219-6.1** Payment shall be made at the contract unit price per square
yard (square meter) for recycled concrete aggregate base course. This
price shall be full compensation for furnishing all materials, for
preparing and placing these materials, and for all labor, equipment
tools, and incidentals necessary to complete the item. Payment will be
made under:

Item P-219-6.1 recycled Concrete Aggregate Base Course -per square yard
(square meter)

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When multiple lifts are shown on the plans, each lift should be measured
and paid separately.

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### TESTING REQUIREMENTS

ASTM C 29 Unit Weight of Aggregate

ASTM C 117 Materials Finer than 75J.lm (No. 200) Sieve in Mineral
Aggregates by Washing

ASTM C 131 Resistance to Abrasion of Small Size Coarse Aggregate by Use
of the Los Angeles Machine

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

ASTM D 693 Crushed Stone, Crushed Slag, and Crushed Gravel for Dry-or
Water- Bound Macadam Base Courses and Bituminous Macadam Base and
Surface Courses of Pavements

ASTM D 698 Moisture-Density Relations of Soils and Soil -Aggregate
Mixtures Using 5.5-lb (2.49-kg) Rammer and 12-in (305-mm) Drop

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

ASTM D 1557 Moisture-Density Relations of Soils and Soil-Aggregate
Mixtures Using 10-lb (4.5-kg) Rammer and 18-in (457-mm) Drop

ASTM D 2167 Density of Soil in Place by the Rubber-Balloon Method ASTM D
2419 Sand Equivalent Value of Soils and Fine Aggregate

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

ASTM D 3017 Moisture Content of Soil and Soil-Aggregate in Place by
Nuclear Methods

ASTM D 3665 Random Sampling of Paving Materials

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

**END OF P-219**

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