Experimental Study on Compatibility between Alkali-Free Liquid Concrete Accelerators and Cement

Abstract

This paper selected two kinds of alkali-free liquid concrete accelerators and tested their compatibility with ordinary Portland cement, Portland cement and moderate heat Portland cement by measuring the setting times, compressive strength and compressive strength ratio of samples. The results showed that the compatibility is good between alkali-free accelerators and two types of cement: ordinary Portland cement and moderate heat Portland cement. However, the compatibility of two accelerators and Portland cement are quite different, the compatibility of AFA-2 accelerator is excellent, but AFA-1 accelerator is very poor. The setting times of alkali-free accelerators is mainly influenced by the mixing materials content, gypsum content, C3A and C3S content. In order to ensure the mechanical properties and durability of concrete, the setting times of new concrete accelerator is not the shorter the better, the appropriate initial and final setting times are 1min30s~5min and 4min~ 12min respectively.