EFFECT OF SILANE MODIFIED POLYCARBOXYLIC SUPERPLASTICIZER ON FLUIDITY AND MECHANICAL PROPERTIES OF CEMENT MORTAR

The performance of concrete slurry is a very important factor in the construction engineering. In this paper, based on silane modification, the molecular structure of polycarboxylic superplasticizer was optimized. The siloxane group with reactivity with cement-based materials was introduced, so as to improve the water reducing performance of water reducing agent. The molecular structure of the new superplasticizer was characterized by FIIR, ¹HNMR and GPC. The adsorption of the water-reducing agent on the surface of cement particles was determined by TOC. The results show that superplasticizer with silane can obviously improved the working performance of the mortar, but also had obvious fluidity retention ability. Because the introduction of silane significantly increased the adsorption amount of water reducing agent molecules in cement particles. At the same time, the introduction of silane decreased the mechanical properties of hardened cement mortars in 1d, because it delayed hydration. However, there was no negative effect on the mechanical properties after 3d, and even the flexural strength of 28d was increased by 13%-37%.