The coarse aggregate of C30 pile cap concrete is composed of 5~25mm and 25~3 1.5mm crushed stones, and it is composed of 5~3 1.5mm continuously graded crushed stones, which are prepared according to the ratio of 5~25mm:25~3 1.5mm=8:2.
The fine aggregate of C30 pile cap concrete is medium sand in Xishui Bahe Ⅱ area, with Mx = 2.7；; External admixture: Wuhan Qingyuan secondary fly ash; Admixture: Wu Peng WP retarding superplasticizer. C30 pile cap concrete is pumped, and the slump is 120mm~ 160mm.
Extended data:
Trial mixing, adjustment and determination of C30 concrete mixture ratio shall meet the following requirements:
1. The raw materials actually used in the project should be used in the trial mix of concrete, and the minimum mixing amount of each plate of concrete should not be less than 25L.
2, try to match, should first try to mix, first check the mixture self-compacting performance must control index, then check the optional index of mixture self-compacting performance. When the self-compacting performance of the mixture obtained by trial mixing cannot meet the requirements. The volume fraction of cementing material, admixture or sand should be adjusted under the principle of constant water-binder ratio and reasonable dosage of cementing material and admixture until it meets the requirements. According to the trial mixing results, the benchmark mix ratio of concrete strength test is put forward.
3. The concrete strength test should adopt at least three different mix proportions. When different mixture ratios are adopted, one of them shall be the benchmark mixture ratio determined in the second paragraph of Article 5.2.2 of this Regulation, and the water-binder ratio of the other two mixture ratios shall be increased and decreased by 0.02 respectively compared with the benchmark mixture ratio; The water consumption is the same as the benchmark mixture ratio, and the volume fraction of sand can be increased or decreased by 65438 0% respectively.
4. When making concrete strength specimens, it should be verified whether the self-compacting performance of the mixture meets the design requirements, and the result represents the performance index of the concrete mixture with corresponding mixture ratio.
5. During the concrete strength test, at least one set of specimens shall be made for each mixture ratio. When the standard curing reaches the age of 28d or the design requirements, pressure test shall be conducted, and several groups of specimens can be made at the same time.
According to the Standard of Test Methods for Early Estimation of Concrete Strength (JGJ/T 15), the early estimation of concrete strength is used to adjust the mix proportion, but it should finally meet the strength requirements of standard curing for 28d or design specified age. If there are durability requirements, the corresponding durability indicators should also be tested.
6. The benchmark mixture ratio should be adjusted according to the test results. For projects with special application conditions, simulation tests should be carried out with the determined mixture ratio to verify whether the designed mixture ratio meets the engineering application conditions.
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