**Construction Specification 762---Grouted Rock Riprap**

**1. Scope**

The work consists of furnishing, transporting, and the installation of
concrete grout in the construction of grouted rock riprap revetments
shown on the drawings.

**2. Material**

**Aggregates** shall conform to the requirements of Section 801, Coarse
Aggregates, and Section 802, Fine Aggregates, of the latest edition of
the Alabama Department of Transportation Standard Specifications for
Highway Construction.

**Portland cement** shall conform to the requirements of Section 815,
Cement, of the latest edition of the Alabama Department of
Transportation Standard Specifications for Highway Construction.

**Fly ash** shall conform to the requirements of Section 806, Mineral
Admixtures, of the latest edition of the Alabama Department of
Transportation Standard Specifications for Highway Construction.

**Air-entraining admixtures** shall conform to the requirements of
Section 808, Air Entraining Additives, of the latest edition of the
Alabama Department of Transportation Standard Specifications for Highway
Construction. If air-entraining cement is used, any additional
air-entraining admixture shall be of the same type as that in the
cement.

**Water reducing and/or retarding admixtures** shall conform to the
requirements of Section 809, Chemical Admixtures for Concrete, of the
latest edition of the Alabama Department of Transportation Standard
Specifications for Highway Construction.

**Curing compound** shall conform to the requirements of Section 830,
Concrete Curing Materials, of the latest edition of the Alabama
Department of Transportation Standard Specifications for Highway
Construction.

**Water used in mixing and curing concrete** shall be clean and free
from injurious amounts of oil, salt, acid, alkali, organic matter, or
other deleterious substances. Water shall conform to the requirements of
Section 807, Water, of the latest edition of the Alabama Department of
Transportation Standard Specifications for Highway Construction.

**3. Design of the grout mix**

The mix proportions for the grout mix shall be as specified in the
construction details in section 10 of this specification. During
installation, the engineer may require adjustment of the mix proportions
whenever necessary. The mix shall not be altered without the approval of
the engineer.

**4. Handling and measurement of grout material**

Material shall be stockpiled and batched by methods that prevent
segregation or contamination of aggregates and ensure accurate
proportioning of the mix ingredients.

Except as otherwise provided in section 10 of this specification, cement
and aggregates shall be measured as follows:

• Cement shall be measured by weight or in bags of 94 pounds each. When
cement is measured in bags, no fraction of a bag shall be used unless
weighed.

• Aggregates shall be measured by weight. Mix proportions shall be based
on the batch weight of each aggregate saturated, surface-dry weight plus
the weight of surface moisture it contains at the time of batching.

• Water shall be measured, by volume or by weight, to an accuracy within
1 percent of the total quantity of water required for the batch.

• Admixtures shall be measured within a limit of accuracy of plus or
minus 3 percent.

**5. Mixers and mixing**

The mixer, when operating at capacity, shall be capable of combining the
ingredients of the grout mix into a thoroughly mixed and uniform mass
and of discharging the mix with a satisfactory degree of uniformity.

The mixer shall be operated within the limits of the manufacturer\'s
guaranteed capacity and speed of rotation.

The time of mixing after all cement and aggregates have been combined in
the mixer shall be a minimum of 1 minute for mixers having a capacity of
1 cubic yard or less. For larger capacity mixers, the minimum time shall
be increased 15 seconds for each cubic yard or fraction thereof of
additional capacity. The batch shall be so charged into the mixer that
some water will enter in advance of the cement and aggregates, with the
balance of the mixing water introduced into the mixer before a fourth of
the total minimum mixing time has elapsed.

When ready-mix grout is furnished, the contractor shall furnish to the
engineer at the time of delivery a ticket showing the time of loading
and the quantities of material used for each load of grout mix
delivered.

No mixing water in excess of the amount required by the approved job mix
shall be added to the grout mix during mixing or hauling or after
arrival at the delivery point.

**6. Conveying and placing**

The grout mix shall be delivered to the site and placed within 1.5 hours
after the introduction of the cement to the aggregates. In hot weather
or under conditions contributing to accelerated stiffening of the
concrete, the time between the introduction of the cement to the
aggregates and complete discharge of the grout batch shall be a maximum
of 45 minutes. The engineer may allow a longer time provided the setting
time of the grout is increased a corresponding amount by the addition of
an approved set-retarding admixture. In any case concrete shall be
conveyed from the mixer to the final placement as rapidly as practicable
by methods that prevent segregation of the aggregates, loss of mortar,
displacement of the rock riprap, or a combination of these.

Grout mix shall not be allowed to free fall more than 5 feet unless
suitable equipment is used to prevent segregation.

The grout mix shall not be placed until the rock riprap has been
inspected and approved by the engineer for the placement of grout.

Rock to be grouted shall be kept moist for a minimum of 2 hours before
grouting.

The rock riprap shall be flushed with water before placing the grout to
remove the fines from the rock surfaces. The rock shall be kept moist
before the grouting and without placing in standing or flowing water.
Grout placed on inverts or other nearly level areas may be placed in one
operation. On slopes, the grout shall be placed in two nearly equal
applications consisting of successive lateral strips about 10 feet in
width starting at the toe of the slope and progressing upward. The grout
shall be delivered to the place of final deposit by approved methods and
discharged directly on the surface of the rock. A metal or wood splash
plate is used to prevent displacement of the rock directly under the
grout discharge. The flow of grout shall be directed with brooms,
spades, or baffles to prevent grout from flowing excessively along the
same path and to assure that all intermittent spaces are filled.
Sufficient barring shall be conducted to loosen tight pockets of rock
and otherwise aid in the penetration of grout to ensure the grout fully
penetrates the total thickness of the rock blanket. All brooming on
slopes shall be uphill. After the grout has stiffened, the entire
surface shall be rebroomed to eliminate runs and to fill voids caused by
sloughing. The surface finish, following the completion of grout
installation, shall consist of one-third of the rock extended above the
level of grout. The exposed rock will not have a plastered appearance.

After completion of any strip or panel, no individual(s) or equipment
shall be permitted on the grouted surface for 24 hours. The grouted
surface shall be protected from injurious action by the sun, rain,
flowing water, mechanical injury, or other potential damaging activity.

**7. Curing and protection**

The completed finished surface shall be prevented from drying for a
minimum curing period of 7 days following placement. Exposed surfaces
shall be maintained in a moist condition continuously for the 7-day
curing period or until curing compound has been applied as specified in
this section. Moisture shall be maintained by sprinkling, flooding, or
fog spraying or by covering with continuously moistened canvas, cloth
mats, straw, sand, or other approved material. Water or moist covering
shall be used to protect the grout during the curing process without
causing damage to the grout surface by erosion or other mechanisms that
may cause physical damage.

The grouted rock may be coated with an approved curing compound as an
alternative method to maintaining a continuous moisture condition during
the curing period. The compound shall be sprayed on the moist grout
surface as soon as free water has disappeared and all surface finishing
has been completed. The compound shall be applied at a minimum uniform
rate of 1 gallon per 175 square feet of surface and shall form a
continuous adherent membrane over the entire surface. Curing compound
shall not be applied to surfaces requiring bond to subsequently placed
grout and/or concrete. If the membrane is damaged during the curing
period, the damaged area shall be resprayed at the rate of application
specified for the original treatment.

Grout mix shall not be placed when the daily minimum temperature is less
than 40 degrees Fahrenheit unless facilities are provided to ensure that
the temperature of the material is maintained at a minimum temperature
of 50 degrees Fahrenheit and not more than 90 degrees Fahrenheit during
placement and the curing period. Grout mix shall not be placed on a
frozen surface. When freezing conditions prevail, rock to be grouted
must be covered and heated to within a range of 50 to 90 degrees
Fahrenheit for a minimum of 24 hours before placing grouting material.

**8. Inspecting and testing fresh grout**

The grout material shall be checked and tested throughout the grouting
operation. Sampling of fresh grout shall be conducted in conformance
with ASTM C 172. The volume of each batch will be determined by methods
prescribed in ASTM C 138.

The engineer shall have free access to all parts of the contractor\'s
plant and equipment used for mixing and placing grout during the period
of the contract. Proper facilities shall be provided for the engineer to
sample material and view processes implemented in the mixing and placing
of grout as well as for securing grout test samples. All tests and
inspections shall be conducted so that only a minimum of interference to
the contractor\'s operation occurs.

For ready-mixed grout, the contractor shall furnish to the engineer a
statement-of-delivery ticket for each batch delivered to the site. The
ticket shall provide as a minimum: weight in pounds of cement,
aggregates (fine and coarse), water; weight in ounces of air-entraining
agent; time of loading; and the revolution counter reading at the time
batching was started.

**9. Measurement and payment**

***Method 1---***For items of work for which specific unit prices are
established in the contract, the volume of grouted rock riprap,
including filter layers or bedding, is determined to the nearest cubic
yard from the specified thickness shown on the drawings and the area on
which acceptable placement has been installed. Payment for grouted rock
riprap is made at the contract unit price. Such payment is considered
full compensation for all labor, material, equipment, and all other
items necessary and incidental to the completion of the grouted rock
riprap, filter layers and bedding, and geotextile material.

***Method 2---***For items of work for which specific unit prices are
established in the contract, the volume of riprap and the volume of
filter layers or bedding is determined to the nearest cubic yard from
the specified thickness shown on the drawings and the area in which
acceptable placement has been installed. The volume of grout is
determined from the calculated batch volume and the number of mixed
batches delivered to the site and placed in accordance with the
specification. The area of geotextile is determined to the nearest
square yard from measurements of geotextile material installed according
to the contract requirements. Payment is made at the contract unit price
for each type of rock riprap, filter or bedding, concrete grout, and
geotextile. Such payment is considered full compensation for all labor,
material, equipment, and all other items necessary and incidental to the
completion of the work.

***Method 3---***For items of work for which specific unit prices are
established in the contract, the quantity of each type of rock riprap
placed within the specified limits is computed to the nearest 0.1 ton by
actual weight. The quantity of each type of filter or bedding aggregate
delivered and placed within the specified limits is computed to the
nearest 0.1 ton. For each load of rock riprap placed as specified, the
contractor shall furnish to the engineer a statement-of-delivery ticket
showing the weight to the nearest 0.1 ton. For each load of filter or
bedding aggregate, the contractor shall furnish to the engineer a
statement-of-delivery ticket showing the weight to the nearest 0.1 ton.
The volume of grout is determined from the calculated batch volume and
the number of mixed batches delivered to the site and placed in
accordance with the specifications and drawings. The area of geotextile
is determined to the nearest square yard from measurements of geotextile
material installed according to the contract requirements. Payment is
made at the contract unit price for each type of rock riprap, filter or
bedding, concrete grout, and geotextile. Such payment is considered full
compensation for all labor, material, equipment, and all other items
necessary and incidental to the completion of the work.

***All methods---***The following provision applies to all methods of
measurement and payment. Compensation for any item of work described in
the contract, but not listed in the bid schedule is included in the
payment for the item of work to which it is made subsidiary. Such items
and the items to which they are made subsidiary are identified in
section 10 of this specification.

**10. Items of work and construction details**

Items of work to be performed in conformance with this specification and
the construction details therefore are:

[Bid Item 19, Concrete Grout]{.underline}

(1) This item shall consist of furnishing and placing concrete grout on
    those portions of the riprap as shown on the drawings.

(2) The grouting mixture shall be as follows:

    a.  Cement: Type IA, Type I or Type II with an air entraining
        admixture, 6 sacks or 564 lbs/c.y.

    b.  Fine Concrete Aggregate: 1,128 lbs./c.y. (surface dry weight)

    c.  Coarse Concrete Aggregate: Pea Gravel, 1,692 lbs/c.y. (surface
        dry weight). Size No. 67, 7 or 8 as per ASTM C-33.

    d.  Water: 45 gal./c.y., or enough to provide a thick creamy
        consistency.

    e.  Air Content: 6 to 10 percent.

(3) Other similar grout mixes that incorporate small coarse aggregate
    may be used but must be approved by the Engineer.

(4) The grout shall be consolidated into the voids with the use of a
    concrete vibrator.

(5) Grouting operation shall not be performed except in the presence of
    the Engineer.

(6) A smooth surface is not to be created by the grouting operation.

(7) The average rate of grout application shall be 1.5 cubic feet of
    grout per square yard of loose rock riprap. Permit the tops of some
    rock to stick up 1 to 3 inches above the neat lines shown on the
    drawings to ensure a rough surface.

(8) Curing compound shall be applied to the grout surface as soon as
    free water has disappeared from the surface of the grout, but shall
    no be applied to any surface until finishing of the surface is
    completed.

(9) Flowing water shall not be allowed in contact with the grout for a
    minimum of 24 hours as approved by the Engineer.

(10) Measurement and payment shall be by Method