On the possibility of modifying cement concrete by spent catalyst for aniline production

The chemical enterprises of the Russian Federation annually produce hundreds of tons of waste that pollutes the environment and requires its disposal. Some chemical wastes contain components that can be used as modifying additives for the production of composite building materials. The conducted study is devoted to improving stress-strain properties of cement concrete modified with the additive of dispersed iron-containing sludge, which is a waste product of aniline production. The compression strength of cement stone, cement-sand mortar and cement concrete, as well as the water resistance of concrete, were determined by standard methods. Moessbauer effect study was used to identify the reasons for increasing the strength of iron-containing sludge-modified cement. The cement paste, mortar and concrete setting kinetics was investigated by the electron-acoustic method. The kinetics of heat generation during Portland cement hydration was determined by the thermos method. The optimal amount of iron-containing sludge additive was obtained by the random method. It was established that the iron-containing sludge additive increases the cement stone strength by 16-18%, cement-sand mortar by 12-14%, cement concrete by 8-10%, reduces water absorption of concrete by 43-45% and increases the cement concrete waterproofing by 60-63%. The optimal amount of the iron-containing sludge additive in cement is 4.0-4.5% by weight of cement.