Abstract:
Te 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
efective 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. Tis 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 difering proportion of
scoria powder was considered as a partial replacement of cement after analyzing its characteristics, and its efect on the fresh and
mechanical properties of hardened concrete was examined. Te 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. Te hardened concrete specimens made with 10%, 20%, and 30% partial
replacement of cement with scoria achieved the specifed minimum strength after 28 days of curing time. But concrete specimens
made with 40% scoria content do not satisfy the minimum specifed concrete strength even after 90 days. Te signifcant 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. Te fndings 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. Tese fndings satisfy the basic strategy of green concrete production in worldwide.
