Utilization of steel wool fibers in AAC blocks containing a mix of flyash, CDW, and glass powder

Abstract

The present article discusses the mechanical performance of autoclaved aerated concrete (AAC) blocks prepared by different constituents i.e., OPC-53, hydrated lime, flyash, and gypsum powder. These constituents are added in specific percentages obtained for AAC with a target density of 800 kg/m3 and their mechanical properties are found. Initially, flyash is used and then subsequently substituted by construction and demolition waste (CDW) and glass powder in 50% and 100% proportions along with the other constituents kept constant to make AAC blocks more sustainable. For this AAC block, the heat curing is done using an accelerated curing tank (ACT) instead of autoclaving and a mixture of alkaline solution in a ratio of (Na2SiO3/NaOH = 1.5) is used instead of aluminium powder for keeping the homogeneity constant throughout all the batches. Further, mechanical performance is enhanced when chopped steel wool fibers (CSWF) are added to the AAC blocks as reinforcement by a 5% weight percentage. For getting more improved mechanical performance heat curing is performed using an ACT at 65 °C ± 5 °C for 10 ± 2 h, which shows block density of the AAC blocks in the range of 1000–1600 kg/m3 with and without steel wool fibers. It is observed that the batches with the inclusion of steel wool fibers has 9–20% gain in compressive strength and a more than 18% increase in flexural strength of the blocks compared to those batches without CSWF. Hence, it is noted that the AAC blocks prepared with 5% CSWF have better mechanical properties. Moreover, a relationship between compressive and flexural strength is established as no Indian standard codebooks provide specific guidelines for determining the flexural strength of AAC blocks. The three different models gave three different relationships and Ellipse curve fitting showing a coefficient of determination (R2) = 0.998.