Study on RCC super retarding compound additive;

The new super setting retarder product(HLC-NAF2) was developed according to the construction characteristics of the bored lock piles,which features in higher dispersiveness and less slump loss,and the setting time can reach 60～80 hours when this product is contained in the concrete.

Werner's theory of coordination and some related theories of 3D chemistry were employed to study molecular structure and characteristics of inorganic and organic retarding admixtures.

Desulphurization render gypsum can be prepared using composite retarder and some tests study on the setting time and mechanical property of desulphurization render gypsum.

The paper introduces that citrin composite retarder restrains nccorete tiny crack icon nstruction of pouring concrete in hot season.

This paper investigated the effects of WH-Ⅱsuper set-retarding agent on the hydration, the heat of hydration, the setting time and strength of Portland cement.

The author does careful research on effects of WH II super set-retarding agent on the hydration, the heat of hydration, the setting time and strength of portland cement, with the methods of XRD, DTA and SEM.

By the experiments of adding WHⅡsuper retarder to cement and concrete, it is found that WHⅡsuper retarder slackens early releasing of hydration heat of the cement, reduces drying shrinkage of concrete, and has no negative effect on corrosion of steel in concrete and freeze-thaw resistance of concrete, and finally improves durability of concrete.

The effects of WHⅡ super retarder on the hydration, the heat of hydration, the setting time and strength of Portland cement were researched by the methods of XRD, DTA and SEM.