No abstract

Cementitious and recycled materials that have the potential to improve various properties of concrete have attracted the attention of many researchers recently. Different types of cementitious and recycled materials seem to possess certain unique properties to change cement concrete. This experimental study aims to investigate the impact of ground granulated blast furnace slag (GGBFS) and corn cob ash (CCA) as a partial replacement material for Portland cement (PC) and fine aggregate (FA), respectively, on fresh and hardened concrete properties, as well as the embodied carbon of concrete. The concrete mix was blended with 5-20% of GGBFS and 10-40% of corn cob ash, both individually and combined. A total of 300 concrete specimens were made to achieve the targeted strength of 25 MPa at a 0.50 water/cement ratio and cured at 28 days. It is observed that the workability of fresh concrete is lowered as the dosages of GGBFS and CCA increase in the mixture. Moreover, the compressive and split tensile strengths are augmented by 10.94% and 9.15%, respectively, at 10% of GGBFS by the weight of PC at 28 days. Similarly, the compressive and split tensile strengths are augmented by 11.62% and 10.56%, respectively, at 30% of CCA by the weight of FA at 28 days. Moreover, the combined use of 10% of GGBFS as a cementitious ingredient along with 30% of fine aggregate replaced with CCA in concrete provides the highest compressive and splitting tensile strength, with 16.98% and 13.38% at 28 days, respectively. Furthermore, the density and water absorption of concrete were reduced with increasing dosages of GGBFS and FA in concrete at 28 days. In addition, the embodied carbon and energy were also reduced as the replacement content of GGBFS along with CCA increased in concrete. It is concluded that 10% of GGBFS and 30% of CCA are the optimum percentages for structural applications to reduce the use of cement as well as the cost of the project.

In recent years, there has been great concern about introducing new supplementary cementitious materials (SCM) in place of Portland cement (PC) in concrete. This study aims to investigate the behavior of sugarcane bagasse ash (SCBA), metakaolin (MK) and millet husk ash (MHA) as SCM with various proportions in concrete. The SCBA, MK and MHA are available in abundant quantities and considered as waste products. On the other hand, cement production emits a lot of toxic gases in the atmosphere which causes environmental pollution and greenhouse gases. Thus, SCBA, MK and MHA might be utilized as cementitious material in concrete for sustainable development. The effect of SCBA, MK and MHA as SCM on the fresh, mechanical properties and embodied carbon of concrete was evaluated experimentally. A total of 228 concrete specimens were prepared with targeted strength of 25MPa at 0.52 water-cement ratio and cured at 28 days. It is found that the compressive strength and split tensile strength were enhanced by 17% and 14.28% respectively at SCBA4MK4MHA4 (88% PC, 4% SCBA, 4% MK and 4% MHA) as ternary cementitious material (TCM) in concrete after 28 days. Moreover, the permeability and density of concrete are being reduced while utilizing of SCBA, MK and MHA separately as SCM and combined as TCM increases in concrete at 28 days respectively. Moreover, the workability of fresh concrete was decreased with the increase of the percentage of SCBA, MK and MHA separately as SCM and together as TCM in concrete. In addition to that, the use of SCBA, MK and MHA individually as SCM and combined as TCM in concrete can reduce the total carbon footprint while reducing the overall cost of concrete manufacturing.

No abstract

No abstract