Preparation of high impermeable and crack-resistance chemical admixture and its mechanism

Abstract

A kind of high impermeable and crack-resistance chemical admixture (HICRCA) was prepared, which is a compound chemical admixture composed of an expansion ingredient, density ingredient, and organic hydrophobic poreblocking ingredient. The results of the experiments indicate that the addition of HICRCA improves mortar and concrete in the following performances: (1) perfect workability: slump is more than 22cm, the slump after 3h is about 16cm; (2) high impermeability: for the mortor, the pervious height under a water pressure of 1.5 MPa is 1.5cm, for the concrete, the pervious height under a water pressure of 5.0 MPa is 2.2cm; (3) high crack-resistance: there is a micro-expansion at the age of 90d; (4) high compressivestrength: compared with the controlled concrete, the compressive strengths at the age of 3d and 28d are improved by 66.4% and 62. 0%, respectively. At the same time, the effects of different curing condition on mortar and concrete expansive and shrinkage performance were studied. In addition, the impermeable and crack-resistance mechanism was investigated in the present paper.