Effect of Nano-Clay on Lightweight Self-Compacting Concrete Behavior

Abstract

In recent years, researchers have also been interested in the production of lightweight self-compacting concrete (LWSCC). Using light weight aggregates to find an alternative to the usual heavy weight concrete. In this study, an experiment was conducted to produce and develop LWSCC to improve some of its properties. Whereas, Expanded Polystyrene (EPS), which is considered a waste polluting the environment, was used as a partial substitute for coarse aggregate to produce lightweight concrete, and Nano-clay (NC) material with microscopic properties in different proportions was used to improve its mechanical properties. The fresh, hardened and mechanical properties of this type of concrete were studied, as a reference mixture of self-compacting concrete and six mixtures of lightweight self-compacting concrete (LWSCC) were prepared, where the coarse aggregate was partially replaced by the lightweight EPS aggregate and part of the cement weight was replaced in different proportions. In this experiment, the fresh properties of LWSCC concrete containing EPS and the effect of adding NC in different proportions, represented by slump flow, T500 and V-funnel, were studied. The hardening properties of this type of concrete, such as density, water absorption, voids, electron microscopy and Ultrasonic Pulse Velocity (UPV), were studied. Where the results showed that the best replacement ratio was NC 2%, which improved the density and within the range of lightweight concrete by 22% after adding NC and replacing part of the coarse aggregate with EPS granules, and reduced the water absorption and voids by 50%, and the concrete moved from doubtful to good. The UPV assay has improved the microstructure of concrete. The mechanical properties, compressive strength (CS) and flexural strength, were studied, which showed that the NC 2% substitution ratio showed the best results. Finally, the study showed that LWSCC concrete produced from EPS waste and NC had reduced density due to the incorporation of EPS particles. The increase in NC material led to segregation in the compression zone due to its entry into microscopic voids and the buoyancy of lightweight materials to the top. While the replacement of 60% from coarse aggregate with EPS granules and replacing 2% of the weight of cement with NC, it showed the best results for hardened concrete.