Research On The Preparation And Crack Resistance At Early-Age Of Concrete With Zeolite Power

Mineral admixture has been widely used in high performance concrete, and the shrinkage and crack are the important factors that affect the durability of concrete. Its price will also rise, as fly ash, silica fume and slag powder were largely used. Therefor, it is a certain significance that zeolite powder is utilized in concrete structure engineering and the influence on the shrinkage and crack resistance of concrete is studied. In this paper, based on Hainan Natural Science Foundation named’Research on Early-Age Crack Resistance of Concrete in Tropical Marine Environment’, mixture ratio design, basic mechanical properties test, dry shrinkage test and flat-slab constraint test of zeolite admixture concrete were studied. The major research work were as follows:(1) C35zeolite admixture concrete was prepared by orthogonal test considering experimental factors that is water-binder ratio, dosage of gelled material, amount of zeolite powder, sand ratio. Meanwhile, the influencing degree of each factor on the strength of concrete was analyzed. The Experimental results showed that workability of C35zeolite admixture concrete was good, and the optimum amount of zeolite powder is20%. Water-binder ratio was the main factor affecting the strength, amount of zeolite powder followed, dosage of gelled material was third, sand ratio was the last one.(2) Workability and mechanical properties of zeolite admixture concrete prepared with the optimal mixing proportion were experimental studied, which were compared with reference concrete. The Experimental results showed that the concrete slump and liquidity were reduced after adding zeolite powder, and the compressive strength and splitting tensile strength were reduced, but flexural strength was slightly increased. Meanwhile, the tension and compression ratio was increased, which can reduce the brittleness of concrete. The relationship between different strength of zeolite admixture concrete was described by the model considering the change of age.(3) Dry shrinkage performance of concrete with different amount of zeolite powder was studied by dry shrinkage test. The results showed that the dry shrinkage value of concrete after adding zeolite powder was increased with the increasing amount of zeolite powder. Exponential expression was used in describe and forecast the dry shrinkage deformation of concrete with different amount of zeolite powder.(4) Early-age crack resistance of zeolite admixture concrete prepared with the optimal mixing proportion was experimental studied by flat-slab constraint test. The results showed that the early-age crack resistance of zeolite admixture concrete was well, but compared with reference concrete, initial cracking time of zeolite admixture concrete wast shortened, and total crack area per unit area was increased, which indicated that early-age crack resistance of concrete was decreased after adding zeolite powder.