SECTION 612 - FLOWABLE FILL
612.01 Description. This work shall consist of furnishing and placing a flowable fill
material. Uses include, but are not limited to, placement under existing bridges, around or within box culverts or pipe culverts, or at other locations shown on the plans.
612.02 Materials. All materials shall meet the requirements of the following
Subsections, or as stated herein: Fine Aggregate............................................................................................. * Portland Cement ............................................................... 701.01 and 701.02 Fly Ash ............................................................................................... 714.05 Air Entraining Admixtures ** ........................................................... 713.02 Water .......................................................................... 714.01.1 and 714.01.2 Calcium Chloride ** ............................................................................ 714.02 * The gradation of the fine aggregate shall be fine enough for the fine aggregate to stay in suspension in the mortar to the extent required for proper flow and shall conform to the following grading: Sieve Size % Passing 1/2 inch 100 No. 200 < 1 ** High air generators shall be used, as required, in order to increase the total air content to 25 – 35%. Only approved high air generators shall be used to obtain the required air content. Either a Type C or E chemical admixture or maximum 1.0% calcium chloride by weight of the total cementitious materials may be added as required by the application and with the approval of the Engineer. Calcium chloride may not be used where the flowable fill comes into contact with metal. Adding the Type C or E chemical admixture or calcium chloride does not require a different or new mixture design from one previously approved.
612.02.1 Mixture Design. Flowable fill is a mixture of portland cement, fine aggregate,
water, and, as required to obtain the required total air content, either high air generators or air entraining admixtures. Fly ash shall be used for Non-Excava table applications. Flowable fill contains a low cementitious content for reduced strength development. At least 30 days prior to production of flowable fill, the Contractor shall submit to the Engineer proposed flowable fill mixtures design following the mixture design submittal procedures listed in the Department’s Concrete Field Manual. The concrete producer shall assign a permanen t unique mixture number to each flowable fill mixture design. All flowable fill mixtur e designs will be reviewed by the Materials Division prior to use. Flowable fill mixture designs disapproved will be returned to the Contractor with a statement explaining the disapproval. Once approved, a flowable fill mixture design may be transferred to other projects without additional testing provided the material sources have not changed. Allowable changes in material sources shall meet the requirements of the Department’s Concrete Field Manual, Section 5.7. For allowable changes in material sources, the mixture design shall be re- verified following the requirements of Subsection 612.02.1.2.
612.02.1 1--Proportioning of Mixture Design. The mixture design proportions shall be
determined based on batches mixed using production equipment. Table 1, “Flowable Fill Mixture Design Proportioning Guide”, is a guide for proportioning flowable fill, except where noted. Table 1 Flowable Fill Mixture Design Proportioning Guide Excavatable Non-Excavatable Material Amount (lbs/yd3) Cement 75 – 150 * 75 – 150 * Fly Ash - 150 – 600 * Fine Aggregate ** ** Water *** *** * Guideline for proportioning. The actual amount may vary from the amount listed the Table 1. ** Fine aggregate shall be proportioned to yield one cubic yard of mixture as verified by unit weight. *** Mixture designs shall produce a consistency that will result in a flowable self- leveling product at time of placement. Each mixture design shall be verified using production equipment prior to submittal of the mixture design for review. During the verification, the mixture design shall meet the requirements of the “Performance Requirements Flowable Fill Design” listed in Table 2. The verification performance data and the corresponding batch ticket shall be submitted with the mixture design. Table 2 Performance Requirements for Verification of Flowable Fill Mixture Designs Mixture Property Performance Requirement Required Test Method Excavatable Non-Excavatable Consistency Approximate 8-inch spread (see below) Total Air Content (%) 25 – 35 5 – 15 AASHTO T121 28 Day Compressive Strength (psi) – Minimum 125 AASHTO T22 and T23 Unit Weight (lbs/ft3) 90 – 110 100 – 125 AASHTO T121 The consistency of the fresh mixture shall be that of a thin slurry. The consistency shall be tested by filling to the top a three-inch di ameter by six-inch high cylinder that is open on both ends. With the mixture in the cylinder, immediately pull the cylinder straight up. The correct consistency of the mixture will pr oduce a spread meeting the requirements in Table 2 with no segregation.
612.02.1 2--Verification of Mixture Design. The verification shall be performed by the
Contractor prior to submittal of the mixture design proportions for review. The verification performance data and the corresponding batch ticket shall be submitted with the mixture design. The verification shall be performed using the batching and mixing equipment anticipated to be used during production of the mixture for the project. In addition to the performance requirements listed in Table 2, the verification shall meet the batching tolerance requirements for the material weights listed in the Department’s Concrete Field Manual.
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