Influence of type and amount of a quartz­containing additives on the properties of mullite­corundum concrete and samples from it

Abstract

An influence of type and amount of a quartz­containing additive (silica fume and pulverized silica) on the properties of concrete and samples from it before and after thermal treatment was investigated. It has been established that, the partial replacement of expensive high­alumina cement in the concrete with the quartz­containing additive improves a flowability of concrete and provides an increase in the strength of concrete samples. Optimal was the addition of domestic pulverized sili-ca in an amount of 2 wt. %.
 The compositions of mullite­corundum and mullite­siliceous mixtures with the pulverized silica addition in the optimal amount and a reduced content of high alumina cement (in comparison with the mullite­corundum concrete manufactured by JSC “URIR named after A. S. Berezhnoy”) have been developed.
 Concrete samples from mullite­corundum concrete of the developed composition with the pulverized silica addition were characterized by a higher cold crushing strength after 3 days of air hardening and thermal treatment at 110 and 1400 C (87 and 108 N/mm2, respectively) compared with samples from mullite­corundum concrete without the quartz­containing additive (52 and 70 N/mm2).
 Petrographic studies have established that, the introduction of quartz­containing additives in the optimum amount in the concrete composition contributes to better sintering of concrete. In the presence of quartz­containing additives in the binder mass of concrete samples, crystallization of mullite and calcium hexaaluminate was intensified, as well as anorthite formation.
 The production of mullite­corundum concrete with the quartz­containing additive (pulverized quartz) has been mastered at JSC “URIR named after A. S. Berezhnoy”.