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