Application of Nanomaterials for Increase of Compressive Strength on Granular Soils to Attain Minimal Damage to the Environment

Nanotechnology will lead to dramatic changes in the use of natural resources, energy, and water, and will reduce wastewater and pollution. One widely-used technique for improving the engineering properties is the use of different additives, and it is worth noting that in the past, these additives included bitumen, lime, fly ash, etc. Among the newest of these additives, one can point to nanoparticles that cause an improvement in physical, mechanical, and in general, geotechnical properties. The aim of this research is to study the effect of two types of nanoparticles, namely, nano silica and nano aluminum oxide, on the compressive strength of poorly graded sand. To this end, different proportions of 0.3, 0.6, and 0.9 percent of the dry cement weight for each nanoparticle, homogenized with cement slurries with water to cement ratios of 1, 1/4, and 1/8, were injected into poorly graded sand with a relative density of 70 percent and a pressure of 2 bar. Based on the compressive strength in 7-day and 28-day samples, it can be understood that the samples’ compressive strength increases with increasing the nanoparticles up to a certain point, and is stopped or reduced after this particular point. Furthermore, the effect of water to cement ratio on the samples’ compressive strength is more than the effect of nanoparticles.