Potential Use of Scoria as a Cementitious Material for Green Concrete Production

Abstract

The demand for cement, which is one of the key components of concrete, is high in Ethiopia, but it is the most expensive and environmentally unfriendly construction material. Due to the increasing concerns about the environment worldwide, researchers have started looking for other resources that can be used to reduce the pollution caused by the cement industry. One of the most effective ways to reduce the pollution caused by the cement industry is by using volcanic scoria powder as a partial replacement for cement in concrete production. Scoria is a locally available natural volcanic material in Ethiopia, especially around the rift valley regions. This natural resource can also be used to reduce energy consumption and the cost of production of cement. To investigate this study, nonprobability sampling techniques were adopted to collect samples from the study area. A differing proportion of scoria powder was considered as a partial replacement of cement after analyzing its characteristics, and its effect on the fresh and mechanical properties of hardened concrete was examined. The test results on the characteristics of scoria revealed that the material is suitable to be used as a supplementary cementitious material in concrete production; hence, its main constituents SiO2 + Al2O3 + Fe2O3 are higher than 70% as per ASTM C618. As the content of scoria powder replacement in cement is increased, it reduces the slump of freshly mixed concrete properties. The hardened concrete specimens made with 10%, 20%, and 30% partial replacement of cement with scoria achieved the specified minimum strength after 28 days of curing time. But concrete specimens made with 40% scoria content do not satisfy the minimum specified concrete strength even after 90 days. The significant strength achievement in scoria blended concrete specimens occurred when moving from 56 to 90 days of curing with 10% replacements. However, in reference specimens, this was observed during 28 days of curing times. The findings of this investigation revealed that scoria powder could replace cement by 30% for the production of normal concrete and it also has the potential to protect the environment from carbon dioxide emissions. These findings satisfy the basic strategy of green concrete production in worldwide.