Cellular lightweight concrete containing high-calcium fly ash and natural zeolite
The research paper investigates the properties of cellular lightweight concrete (CLC) produced using high-calcium fly ash (FA) and natural zeolite (NZ) as partial replacements for Type-I Portland cement (OPC). The study focuses on the effects of varying replacement levels (0%, 10%, 20%, and 30% by weight) of OPC with FA and NZ on the compressive strength, setting time, water absorption, and microstructure of the CLC.
The research finds that CLC with a density of approximately 800 kg/m³ can achieve significant compressive strength improvements, particularly with 10% NZ replacement, which yields the highest strength. The study reveals that the incorporation of NZ reduces total porosity and air void size while increasing capillary porosity compared to FA. The results indicate that as the replacement level of pozzolans increases, the setting time also prolongs, with NZ mixtures setting slightly faster than those with FA.
Water absorption tests show that CLC containing NZ exhibits lower water absorption than those with FA, attributed to the reduction in pore size and the effective filling of voids by finer NZ particles. The microstructural analysis, including scanning electron microscopy (SEM) and X-ray diffraction (XRD), confirms that the addition of pozzolans enhances the density and reduces the porosity of the concrete, with NZ demonstrating superior performance in this regard.
The study concludes that the optimal replacement level for both FA and NZ is 10%, which significantly enhances the compressive strength compared to the control mix. However, higher replacement levels lead to decreased strength due to reduced OPC content and slower pozzolanic reactions.
This research paper is significant in the field of civil engineering and materials science, particularly in the context of sustainable construction practices. By exploring the use of industrial by-products like fly ash and natural zeolite, the research contributes to ongoing discussions about reducing the environmental impact of concrete production. The findings provide valuable insights into optimizing the properties of lightweight concrete, which is crucial for applications in building construction where weight reduction and thermal insulation are essential. The study also highlights the potential for utilizing locally available materials, promoting resource efficiency and sustainability in construction.
