Cellular concrete waste as an economical alternative to traditional supplementary cementitious materials

Abstract

Traditional supplementary cementitious materials (SCMs), like metakaolin or microsilica, highly improve various properties of concrete, making it more resistant against the effects of the environment. However, the cost of concrete is highly influenced by the applied amount of SCMs. Cellular concrete powder (CCP) is a by-product, produced by the cutting and curving process of cellular concrete blocks, which has the possibility to be used for similar purposes as SCMs. The present paper introduces the results of the laboratory experiments, conducted by the authors, and their analysis. The experiments were designed to investigate the effects of CCP on mortars, normal and high-strength concretes in terms of strength and durability. To get a deeper understanding of the processes taking place in a mortar or concrete containing CCP, thermogravimetric analysis was performed as well. CCP was applied in the mixes in different amount, and the performance of CCP was compared to SCMs. CCP was found to be a feasible alternative to SCMs in case of normal-strength concrete, while in case of high-strength concrete it did not improve the strength of the reference concrete. It could be traced back to the sulfate swelling of CCP particles. In optimal dosage, CCP was found to be preferable to metakaolin (MK) for durability characteristics. The combined usage of CCP and MK was investigated as well, but it did not result a concrete with better performance than the reference mix.