自燃煤矸石掺合料与高效减水剂相容性研究

Experimental Research on Compatibility of Spontaneous Combustion Gangue Admixture with Superplasticizer

自燃煤矸石易粉磨,比表面积较大、吸附水较多、表面能较高,若不与具有表面活性的高效减水剂复掺,很容易形成絮凝结构,降低水泥浆的流动性,不仅不能满足预拌混凝土的泵送要求,也影响硬化混凝土强度。本文首先采用胶砂对比试验,分别将不同粉磨时间的自燃煤矸石粉30%取代水泥,以自燃煤矸石-水泥胶砂强度较高者确定粉磨时间;在此基础上,选择自燃煤矸石粉掺量、减水剂品种和掺量为影响因素,通过正交试验研究自燃煤矸石粉与两类不同减水剂的相容性。结果表明,自燃煤矸石作混凝土掺合料经济粉磨时间为4~6 min,与两类减水剂相容性程度为：聚羧酸系〉奈系。自燃煤矸石粉无论与哪类减水剂双掺,建议自燃煤矸石粉掺量≤15%,而聚羧酸系减水剂掺量≤0.43%,奈系减水剂掺量≤0.8%。

SCGP （spontaneous combustion gangue powder） is easy to form the flocculation structure and reduces the liquidity of the slurry, it not only dissatisfies the pumping requirement of the premixed concrete, but also affects the strength of hardened concrete, if it is not mixed with superplasticizer having surface activity. Becouse SCG（ spontaneous combustion coal gangue）is easier to grind and its power have the characteristics of larger specific surface area, more adsorption water and higher surface energy. At first, the paper adopts the comparative test of mortar, using 30% SCGP under different grinding time to replace cement and determine the grinding time by the higher SCGP-cement mortar strength. On this basis, compatibility of SCGP with two kinds of water reducer can be researched by orthogonal experiment, choosing the proportion of SCGP and the varieties and proportion of water reducer as influencing factors. The results show that economic grinding time of SCG as admixture of concrete is four to six minutes and the degree of compatibility with two kinds of water reducer is Poly （polycarboxytate） 〉 Nap（naphthalene）. No matter which kind of water reducer mixing with SCGP, suggested proportion of SCGP is 15% or less, Poly is 0.43% or less and Nap is 0.8% or less.