| Pumping concrete is very popular in the construction of modern concrete structures, it makes the construction more rapidly and more efficiently, and it can alleviate the labor intensity of the workers. Hoeever, pumping concrete brings on many problems to the projects, such as the early age cracking of cast-in-place floor, which has already become the common quality fault.By testing concrete with ring specimens and other tests for mechanical properties of pumping concrete, this paper analyzed early age cracking properties of pumping concrete.Firstly, the pumping concrete were tested at 1, 2, 3, 5, 7, and 14 days after casting to determine the splitting tensile strength and elastic modulus, and the data were analyzed using the software Origin 7.5. The relation between tensile strength and age of the concrete was described using formula gained from the analysis with Origin 7.5. At the same time, the pumping concrete specimens in the similar drying condition as the ring specimens were tested for early age free shrinkage. The data of shrinkage were analyzed by software Origin 7.5, and the relation between shrinkage and age was described in the form of a formula. Then, ring tests were used in this paper to measure the inside surface strain of the steel ring. At last, the test setting was theoretically analyzed by mechanics of elasticity, and the theoretical stress and actual stress of ring specimens were calculated. In combination with the test of tensile strength, evaluation on cracking potential and stress relaxation of ring specimens was made. With all the above, the evaluation on cracking characteristics of pumping concrete at early age is realized.Concrete specimens with different constituent materials were tested in this paper. Test result indicated that the quantity of pumping agent, water, and cement used in concrete influenced the cracking properties of pumping concrete. The quantity of pumping agent, water, and cement should be properly chosen in construction.
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