Estimation of the Content of Stone Fine Powder in High-Performance Lightweight Rice Husk Concrete Blocks

Abstract

Stone fine powder (SFP) is a solid by-product of the stone-cutting industry, which causes land and air pollution in the surrounding areas. In this study, SFP was used as a raw material in the manufacturing of lightweight material of SFP-based rice husk concrete blocks (RHCBs), and its optimal content to meet the performance of Indonesian standards was determined. The RHCBs studied here were composed of three materials: cement (binder), SFP, and raw rice husk (RRH). Samples were grouped into three batches: Batch-I, Batch-II, and Batch-III with binder-RRH ratios of 1:2, 1:3, and 1:4 respectively. Moreover, six binder-SFP ratios were tested in each batch, i.e., 1:0.25, 1:0.50 1:0.75, 1:1, 1:1.25, and 1:1.50. Thus, 18 mixes were cast to assess the performance of the SFP-based RHCBs. The results revealed that the increase of the SFP content in concrete mixture significantly enhances the density and compressive strength of SFP-based RHCBs, due to their denser structure. The SiO2 as the majority component of SFP does not have an impact on improving RHCB strength because it is chemically inactive. SFP-based RHCB with 300% RRH and the ratio of SFP to binder = 92.82–105.49% is the optimal choice. For practical purposes, it can be regarded as 100% SFP. This synergetic application of binder:SFP:RRH = 1:1:3 in a concrete mixture will generate the best SFP-based RHCB, with a density of around 1,345.22 kg/m3 and a compressive strength of approximately 2.80 MPa.