REDUCTION OF CEMENT CONSUMPTION BY THE AID OF SILICA NANO-PARTICLES (INVESTIGATION ON CONCRETE PROPERTIES)

Hadi Bahadori,Payam Hosseini

doi:10.3846/13923730.2012.698912

Abstract

In this study, effects of replacing cement with colloidal amorphous silica nano-particles have been experimentally investigated on the physical and mechanical properties, durability and microstructure of concrete. Experimental results include workability, fresh concrete density, and hardened concrete properties like compressive strength at different ages of 3, 7, and 28-days, and also 28-days splitting tensile strength. Furthermore, influence of silica nano-particles on durability and microstructure of concrete for 28-days specimens was tested by conducting water absorption test, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Analysis (EDAX), respectively. In order to study the effect of replacement of cement with silica nano-particles, specimens with 10%, 20%, and 30% cement reduction, and addition of 1%, 2%, and 3% silica nano-particles with respect to witness specimen were fabricated. Experimental results revealed that 20% reduction of cement combining 2% silica nano-particles and also 10% cement reduction combined with 1% silica nano-particles enhance the microstructure of concrete, despite unnoticeable compressive and tensile strength loss. By remarkable reduction of cement consumption and addition of silica nano-particles, strength almost remains constant and consequently decreasing the cement content will become possible. Also, in all specimens, increase in nano-particles content and decrease in cement usage contributed to workability loss. Therefore, applying super-plasticizers seems indispensible while using silica nano-particles. On the other side, according to water absorption test, concretes containing nanoparticles showed more appropriate durability.

Highlights

Due to development of concrete constructions throughout the world, it can be seen that the cement usage has been increased
The importance of this issue is in such a way that the topic of cement reduction is propounded as one of the principal keys in achieving a sustainable development in concrete industry (Damtoft et al 2008; Ortiz et al 2009; Bahadori et al 2009; Khaloo, Hosseini 2009)
Various types of pozzolans such as class F fly ash, slag, silica fume, rice husk ash were recognized and utilized to enhance the concrete quality (Hale et al 2008; Penpolcharoen 2005; Roy et al 2001; Li, Zhao 2003; Chung 2002; Ramezanianpour et al 2009). It is not a long time passed from the entrance of nano-technology in concrete industry, many researches and investigations claimed the positive effects of nano-materials and nano-powders on microstructure and macrostructure of concrete (Li et al 2004b; Jo et al 2007; Qing et al 2007; Hosseini et al 2010a, b; Senff et al 2009, 2010)

Summary

Introduction

Due to development of concrete constructions throughout the world, it can be seen that the cement usage has been increased. It could be mentioned other different reasons for slump reduction from witness mixture to D1 such as increase in silica nano-particles and aggregate volume and decrease in water and cement content.

Results

Conclusion