Aiming at the problem of the commonly seen early cracking of the high performance concrete,a study is given here on the effects of the additional polypropylene fiber and the active admixtures on the deformation property and the resistance to the plastic-contraction caused cracking and the dry-contraction caused cracking and also another study on the comprehensive performances,such as the mechanical properties,the ultimate tensile strain;the dry contraction and the chloride ion penetration,of the C 40 high performance concrete.The results from the studies indicate that by adopting the large-circle test method and the plate test method,a better evaluation can be got of the cracking property of concrete and mortar and the C 40 high performance concrete with 0.9 kg·m-3 polypropylene fiber and 20 % of admixture(10 % of slag and 10 % of fly ash) has good working performance and mechanical property and it’s resistance against chloride ion penetration is improved,its ultimate tensile strain raised,and its cracking resistance obviously made.
