Properties of foamed fine-grained composites containing active mineral admixture

Environmental regulations related to excessive mining of raw natural materials for primary production of Portland cement, cement-based composites respectively enforce the application of post-industrial wastes and by-products representing an alternative material source. These materials in combination with chemical additives help ensure desired material savings. In this sense, the utilization of active diatomite admixture and foaming additive in production of fine-grained composites and lightweight composites was researched in the paper. First, composite mixture with 20% volume replacement of Portland cement with diatomite and water/binder ratio of 0.5 was prepared. Then, it was enriched by foaming agent in the dosage of 0.7 ml/kg of a binder. Corresponding control materials based on Portland cement as the only binder were made as well. For the hardened materials cured for 28 days, basic structural properties, mechanical properties, and heat transport and storage parameters were assessed. Experimental investigation revealed a combined action of pozzolanic activity and filler effect of diatomite admixture leading to a reduction in the total open porosity and imrpvement of mechanical resistance of produced composites. Highly porous cellular structure of foamed composites resulted in an important strength drop. However, materials with low unit weight and excellent thermal performance were developed.