WYDOT CONCRETE MIX DESIGN PROCEDURE Scope: This procedure documents the requirements for obtaining a concrete mix design or referencing an approved mix design from the WYDOT Materials Program, and the amounts of concrete aggregate, cementitious material, and admixtures that are to be submitted. It also addresses the procedure for developing and obtaining approval for a silica fume concrete mix design. This procedure applies to all concrete placed separate from Quality Control/Quality Assurance specifications. Use: This procedure will be used to determine the steps to follow and the amounts of concrete constituents (including aggregate, cement, fly ash, silica fume, chemical admixtures, etc) that must be collected and submitted to the WYDOT Materials Program for the purpose of running a mix design or conducting test batches. Reference Documents: WYDOT 472.0 Contractor Concrete Mix Design Procedure WYDOT 816.0 Sieve Analysis of Concrete Aggregate WYDOT E-45 Concrete Mix Design WYDOT T-100 Report of Tests on Concrete Mix Designs WYDOT T-120 Sample Transmittal Procedure: Check the plans to determine the classes of concrete and types of cement called for. A mix design will be required for each different class of concrete, including modified mixes, for each type or source of cement used on the project, or for any change in admixtures. For each mix design, a WYDOT Form E-45 will be completed by the contractor or supplier, sent through the WYDOT engineer, and finally forwarded to the WYDOT Materials Program, a minimum of 35 days before concrete placement. Concrete placement may begin on receipt of the T- 100 from the Materials Program. Run a gradation test on the coarse and fine aggregate using the procedure outlined in WYDOT 816.0 Sieve Analysis of Concrete Aggregate before the material is sent to the WYDOT Materials Program. A mix design will not be performed on out of specification material. Submit all mix designs through the Resident Engineer s office for proper processing prior to being sent to the Materials Program. A mix design will not be performed on out of specification material. Along with the Form E-45, and the necessary Form T-120 for each material submittal, submit the following quantities of materials to the WYDOT Materials Program for the appropriate mix designs: Submit ALL aggregate samples in standard canvas bags, 30 lb - 50 lb in each bag. For liquid admixtures submit 1 quart of each type. 1
Structural Concrete Aggregate: 600 lb of coarse aggregate 400 lb of fine aggregate For each additional mix design on the same project from the same source, send 270 lb of coarse aggregate and 200 lb of fine aggregate that will be needed for each mix design. Aggregate samples will be sent to the WYDOT Materials Program a minimum of 35 days prior to construction intended use. P.C.C.P Aggregate: Fly Ash: 775 lb of coarse aggregate 600 lb of fine aggregate For each mix design on Portland Cement Concrete Pavement (PCCP) mix design. Representative samples of coarse and fine aggregate should be sent to the WYDOT Materials Program as soon as possible and a minimum of 35 days before the aggregate will be used in construction. The samples sent in for mix designs are not check samples and cannot be used as such. Check samples are taken only during production. When fly ash is to be used in the concrete mix design, a fly ash sample should be taken for the project. Send 50 lb of fly ash and ship it in plastic bucket(s) or container(s). Portland Cement: Record on Form T-120 the class of fly ash used, the manufacturer's name, and the invoice number if possible. It will not be necessary to record the contractor's name or the name of the ready mix company. A Portland Cement sample should be taken for each source and type of cement used on the project. The sample must be free of any soil or rocks. Send 140 lb of cement and ship it in plastic bucket(s) or container(s). A Portland Cement sample should be taken for each source and type of cement used on the project. 2
Record on Form T-120 the type of cement used, the manufacturer's name, and the invoice number if possible. It will not be necessary to record the contractor's name or the name of the ready mix company. Silica Fume: A silica fume concrete mix design must be developed by the contractor with the aid of an admixture manufacturer prior to requesting mix design approval from the WYDOT Materials Program. Batching proportions and batching sequence must be determined by this process. Results of this mix development will be submitted to the WYDOT Materials Program when requesting mix design approval. A Laboratory test mix will be conducted by the WYDOT Materials Program utilizing these instructions. If the proposed mix design does not provide a satisfactory mix, as determined by WYDOT Materials Program, the contractor must resubmit a revised mix design. The contractor will provide the following items to the WYDOT engineer at least 30 days prior to placement: 1. A completed Form E-45 indicating all materials to be used, including the manufacturer and source for all materials. 2. A letter indicating proportions of all materials, including water. The aggregate proportions will indicate whether they are saturated, surface dry condition or dry condition. Total or net water will also be indicated as appropriate based on aggregate condition. 3. An equipment letter indicating the mixing equipment to be used. 4. A batch sequence letter indicating the sequence of material batching and mixing times. 5. Submit sufficient samples of all mix constituents so that a test mix may be batched at the WYDOT Materials Program. 3
Referencing Mix Designs: Sufficient samples will be a minimum of: 100 lb of cement 400 lb of coarse aggregate 300 lb of fine aggregate 25 lb of silica fume 1 lb of fibers 1 quart each of all liquid or dry admixtures (which includes normal and high-range water reducers and air-entraining admixture). No more than two mix designs for each placement location will be batched by the WYDOT Materials Program at no cost to the contractor. The contractor will be charged a fee for each additional mix design confirmation. The contractor must conduct a trial batch prior to placement to verify in-field conditions, utilizing stockpiled aggregate as proposed for the project and simulating proposed haul distance. Trial batch material may not be used in the resurfacing work. If a proposed mix design is composed of identical components to a previous mix design, the previous mix may be referenced if less than two years old. In such cases, aggregate analysis only will be required. Send 100 lb of coarse aggregate and 100 lb of fine aggregate along with Form E-45 showing all mix design components to the WYDOT Materials Program for testing. For silica fume concrete, referencing to avoid the laboratory test mix will only be allowed within one year of use. The on-site trial batch will always be required. Mix Design Approval: The WYDOT Materials Program will determine acceptability of all mix designs and reference designs upon determination of mixture properties and strength development trends. Upon approval, a copy of Form T- 100PE or Form T-100SE (see example forms in WYDOT 472.0), with the mix design proportions used, mix consistency results, and strength results, will be forwarded to the WYDOT engineer. Concrete placement may begin upon receipt of Form T-100PE, or Form T-100SE. 4
5 WYDOT 471.0
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