Experimental Study on Early Drying Shrinkage of Self-compacting Barite Concrete

Abstract

In this paper, raw materials such as fly ash-S95 grade mineral powder composite mineral admixture, barite coarse and fine aggregate and polycarboxylic acid water reducer are selected to successfully formulate C30 self-compacting barite concrete with good performance. It also analyzes the development law of early drying shrinkage of self-compacting barite concrete with age, and discusses the effects of fly ash and slag mixing ratio and water reducer content on concrete work, compressive strength and early drying shrinkage. The results show that: the drying shrinkage of self-compacting barite concrete develops rapidly within 1 day of age, and the drying shrinkage rate at 1 day accounts for 50% to 66% of that at 7 days of age, and then the growth trend is slow; as the proportion of fly ash increases, the performance of the concrete mixture improves. While the strength of concrete decreases in the early and mid-term, the strength gradually increases in the later period, and the shrinkage strain of concrete in the early stage also increases significantly; the proper amount of water-reducing agent can greatly improve the fluidity of the mixture. In the dosage range of 1.2%~1.4%, with the increase of the amount of water reducing agent, the compressive strength first increases and then decreases, reaching the maximum when the dosage is 1.3%, and the early drying shrinkage strain of concrete increases slightly.