Feasibility Study on the Use of Compost as Fine Aggregate in Lightweight Concrete

Industrial and organic by-products are increasingly being utilized in many forms in construction. This is being practiced to lower the negative effects on the environment. Numerous studies have been done using alternate materials in concrete to diminish their environmental impact. This study emphasizes the making of lightweight concrete in which compost is replaced for M sand at 0, 10, 20, 30, 40, and 50%. The mechanical properties of the concrete made with compost were initially studied, which revealed that with the increase in the compost percentage, the strength of the concrete decreased. Then, Ground Granulated Blast Furnace Slag (GGBS) is added as a replacement in cement at 5, 10, and 15% along with compost to check whether the cementitious material will enhance the concrete property. Then, the specimens were tested for mechanical and durability properties with GGBS. From the mechanical property results, it was observed that compost can be replaced up to 20% along with GGBS in concrete making. It is observed that the concrete with compost till 20% for M sand with the inclusion of GGBS for cement possessed better microstructure with the formation of C-S-H gel. The durability test is carried out on the optimal concrete obtained from mechanical studies. The concrete specimens up to 20% compost showed better results for durability. The concrete specimens containing compost were tested for degradation to assess the impact of compost addition on the concrete properties. Interestingly, bacteria heal the pores in concrete by secreting calcium carbonate, thus enhancing the concrete’s properties.