Mechanical and Microscopic Investigation of Concrete Incorporating Ceramic Waste Powder as Partial Replacement of Binding Material

Abstract

Concrete is the most important construction material in construction industry. The ceramic industry generates large amounts of pozzolanic clay wastes every year in Bangladesh and worldwide. So far massive parts of ceramic wastes (CW) are directly dumped into the landfills. Reusing the ceramic wastes in concrete would be the sustainable solution. Also, it leads to avoid the environmental problems related to landfill wastes. Generally, two types of ceramic wastes are found in the ceramic industry such as white and red ceramic waste. This study investigates the mechanical properties and microscopy of concrete incorporating the ceramic waste powder as partial replacement of cement. In this research work, chemical composition by X-ray fluorescence (XRF) analysis, compressive strength test, splitting tensile strength test, X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) analysis were conducted on cement and partially replaced ceramic waste powder (CWP) concrete. The partial replacement proportions of cement by CWP were 0%, 5%, 10%, 15%, 20%, 25% and 30%. Ceramic wastes powders have been made by ball machine to conduct XRF analysis, mechanical and microscopic investigation. Total 195 cylinders have been made to perform mechanical properties in this research, where 117 cylinders were used for compressive strength test and 78 cylinders were used for splitting tensile strength test. Specific samples have been prepared to conduct microscopic investigation i.e. XRD and SEM analysis. The XRF analysis illustrated that the SiO2 and Al2O3 exist in ceramic powder (both red and white) which is almost twice that of cement. The XRF analysis of red and white ceramic powder provided satisfactory results compared to ASTM specification of Portland cement, fly ash, slags and control cement. Analyzing and illustrating the compressive strength test and splitting tensile strength test results, the CWP concrete provides satisfactory mechanical properties. The most favourable proportion in concrete for red and white ceramic waste powder were found 20% and 15% of partial replacement of cement respectively. The partially replaced CWP concrete presented satisfactory results up to most favourable mix proportions considering modulus of elasticity, stress-strain diagram and Poisson’s ratio of cement concrete, although, the modulus of elasticity calculated by ACI and ASTM methods have minor variations. The alite and tobermorite is the most dominating compound found in the XRD analysis of CWP concrete samples. Based on the XRD investigation, it was revealed that the intensity of alite and tobermorite of CWP concrete is greater than control specimen. From the SEM analysis, it was observed that with the increase of curing ages the alite was hydrated, tobermorite developed and jointly formed a continuous matrix. The density of the surface morphology was very denser of red and white CWP concrete than cement concrete samples. The red CWP concrete specimens were denser and compact having lesser microcracks than cement and white CWP concrete. Therefore, this study revealed that the ceramic waste powder (CWP) provides better performance and hence, it can be used in concrete as partial replacement of binder (cement) up to certain proportion. Also, reusing the ceramic wastes in concrete industry would be the win-win solution considering the costs of cement production and environmental related problems.