Optimization of nano silicon for integral mixing in cement mortar: A response surface methodology approach

Abstract

Water penetration into concrete structures can causse alots of problems such as reinforcement corrosion, aesthetic of building façade, cracks and other forms of degradation. A number of waterproofing admixtures are currently used to avoid these problems. In the same time, it was used to increse the service life of concrete. This study investigates and established waterproofing performance of nano silicon based mortar. In this regard, nano silicon was characterized using water contact angle and nuclear magnetic resonance Response Surface Methodology (RSM) was employed to establish the optimum amount of nano silicon. The relationship between the experimental factors (nano silicon dosage and water cement ratio) and response (compressive strength) was modelled and validity of the model was further evaluated to ensure accurate predictions. Optimum amount of nano silicon, necessary to reduce water absorption was established at nano silicon dose of 6.6% by weight of cement. The results indicated that water absorption resistance to increased to 63%. In addition, FESEM and XRD micrographs indicate the formation of a crystalline hydrophobic thin film layer of nano silicon within the pore structure of the mortar specimen. In conclusion, nano silicon can be used as waterproofing admixture.