121-1 Description.
Furnish and place flowable fill as an alternative to compacted soil as approved by the Engineer. Applications for conventional flowable fill include beddings ; encasements ; closures for tanks and pipes; and general backfill for trenches, embankments and walls. Applications for cellular concrete flowable fill include beddings ; encasements ; closures for tanks and pipes; and general backfill for embankments and walls.
121-2 Materials.
Meet the following requirements: Fine Aggregate(1) ................................ ................. Section 902 Portland Cement ................................ .................. Section 921 Water ................................ ................................ ...Section 923 Admixtures(2)................................ ....................... Section 924 Ground Tire Rubber (GTR)(3) ............................. Section 919 Supplementary Cementitious Materials ..............Section 929 Preformed Foam ................................ ................ ASTM C869
1.Any clean fine aggregate with 100% passing a 3/8 -inch mesh sieve and not more than 15% passing a No. 200 sieve may be used.
2.High air generators or foaming agents may be used in lieu of conventional air entraining admixtures and shall be added at jobsite and mixed in accordance with the manufacturer’s recommendation. GTR may reduce the amount of h igh air generators or foaming agents used.
3.GTR may replace up to 20% of the fine aggregate.
121-3 Mix Design.
Conventional flowable fill is a mixture of portland cement, fly ash, fine aggregate, admixture and water. Flowable fill contains a low cemen titious content for reduced strength development. Cellular concrete flowable fill is a low density concrete made with cement, water and preformed foam to form a hardened closed cell foam material. Cellular concrete flowable fill may also contain fine aggre gate, supplementary cementitious materials and admixtures. Submit mix designs to the Engineer for approval. T able 121-1 below has suggested mix guides for excavatable, non -excavatable and cellular concrete flowable fill: FY 2023-24 Return to Table of Contents Table 121-1 Excavatable Non-Excavatable Cellular Concrete Cement 75-100 lb/yd3 75-150 lb/yd3 Min 150 lb/yd3 Supplementary Cementitious Materials None 150-600 lb/yd3 Optional Water * * * Air** 5-35% 5-15% **** 28 Day Compressive Strength** Maximum 100 psi Minimum 125 psi Minimum 80 psi Unit Weight ** 90-110 lb/ft3 100-125 lb/ft3 20-80 lb/ft3 Fine Aggregate *** *** Optional *Mix designs shall produce a consistency that will result in a flowable self -leveling product at time of placement. **The requirements for percent air, compressive strength and unit weight are for laboratory designs only and are not intended for jobsite acceptance requirements. ***Fine Aggregate shall be proportioned to yield 1 yd3. ****In cellular concrete, preformed foam sh all be proportioned at the job site to yield 1 yd3 in accordance with the design requirements.
121-4 Production and Placing.
Use flowable fill manufactured at a production facility that meets the requirements of
347-3 Deliver flowable fill using concret e construction equipment. Revolution counter are
waived. Place flowable fill by chute, pumping or other methods approved by the Engineer. Tremie flowable fill through water. Cellular concrete flowable fill may not be placed within three feet of the bottom elevation for roadway base courses.
121-5 Construction Requirements.
Use straps, soil anchors or other approved means of restraint to ensure correct alignment when flowable fill is used as backfill for pipe or where flotation or misalignment may occur. Protect flowable fill from freezing for a period of 36 hours after placement. Place flowable fill to the designated fill line without vibration or other means of compaction. Do not place flowable fill during inclement weather, e.g. rain or ambient temperatures below 40ºF. Take all necessary precautions to prevent any damages caused by the hydraulic pressure of the fill during placement prior to hardening. Provide the means to confine the material within the designated space.
121-6 Acceptance.
Acceptance of flowable fill will be based on the following documentation and a minimum temperature of flowable fill at the point of delivery of 50ºF. Submit a delivery ticket to the Engineer for each load of flowable fill delivered to the worksite. Ensure that each ti cket contains the following information:
1.Project designation,
2.Date,
3.Time,
4.Class and quantity of flowable fill,
5.Actual batch proportions,
6.Free moisture content of aggregates,
7.Quantity of water withheld. Leave the fill undisturbed until the material obtains sufficient strength. Sufficient strength is 35 psi penetration resistance as measured using a hand held penetrometer in FY 2023-24 Return to Table of Contents accordance with ASTM C403. Provide a hand held pene trometer to measure the penetration resistance of the hardened flowable fill.
121-7 Basis of Payment.
When the item of flowable fill is included in the Contract, payment will be made at the Contract unit price per cubic yard. Such price and payment will i nclude all cost of the mixture, in place and accepted, determined as specified above. No measurement and payment will be made for material placed outside the neat line limits or outside the adjusted limits, or for unused or wasted material. Payment will b e made under: Item No. 121 - 70- Flowable Fill - per cubic yard. FY 2023-24 Return to Table of Contents SECTION 125 EXCAVATION FOR STRUCTURES AND PIPE
125-1 Description.
Excavate for box culverts, pipes, retaining walls, headwalls for pipes and drains, catch basins, drop inlets, manholes, and similar structures. Construct and remove cofferdams, sheeting, bracing, etc.; pump or otherwise dewater foundations; remove and dispose of any existing structures or portions of structures not covered by other items in the Contract, including foundations, abutments, piers, wings, and all other materials, obs tructions, etc., found necessary to clear the site for the proposed work; backfill, dispose of surplus material, and perform final cleaning, as may be necessary for the proper execution of the work. This Section does not include excavation for bases or pav ements, curbs, curb and gutter, valley gutter, ditch pavement, or rubble gutter.
125-1.1 Trench Excavation Safety System and Shoring, Special (Trench
Excavation): When performing trench excavation in excess of 5 feet in depth, comply with the Occupational Safety and Health Administration’s (OSHA) trench safety standards, 29 CFR 1926, Subpart P, and all subsequent revisions or updates adopted by the Department of Labor and Employment Security. Ensure that trench boxes are wide enough to accommodate compacti on and density testing. Submission of bid and subsequent execution of the Contract will serve as certification that all trench excavation in excess of 5 feet in depth will be in compliance with Section 553.62, Florida Statutes. Consider all available g eotechnical information when designing the trench excavation safety system. Consider these and any more stringent trench safety standards as minimum Contract requirements.
125-2 Classification.
Consider all materials excavated as unclassified and as exc avation regardless of the material encountered.
125-3 Cofferdams.
125-3.1 Construction:
125-3.1 1 Methods: Construct all foundations by open excavation, and shore,
brace, or protect the foundation openings with cofferdams. Provide cofferdams or cribs fo r foundation construction below the bottom of the footings. Provide sufficient clearance in the cofferdam interiors to permit construction of forms and inspection of their exteriors, and for pumping equipment.
125-3.1 2 Protection of Concrete: Construct cofferdams to protect green
concrete against damage from a sudden rising of the water and to prevent damage by erosion. Do not leave timber or bracing in cofferdams or cribs that extend into the substructure masonry except where permitted in writing by the Engineer.
125-3.1 3 Placing in the Dry: For placing footings in the dry, the Engineer may
require cofferdam sheeting to be driven to an elevation 6 feet below the elevation of the bottom of the footings and require sufficient pumping equipment to dewate r and maintain the cofferdam in a comparatively dry condition. FY 2023-24 Return to Table of Contents
Source: Florida Standard Specifications for Road and Bridge Construction, 2024 Edition. Pages 202–204 of 1,299.