Laboratory Investigation on Durability of Nano Clay Modified Concrete Pavement
Keywords:compressive strength, flexural strength, nano clay, penetration, absorption percent
Today, one can take a strategy to improve durability in concrete coatings by using modern materials, especially nano-materials. Nano clay is one of the nanoparticles that increases mechanical properties and strength in concrete. With respect to very rich deposits for clay sources in properties of concrete it seems necessary to conduct studies in this regard. Nano clay was utilized with percentages of 1wt%, 2wt% and 3wt% in this study. The effects of both types of water curing and plastic cover curing were examined. The results indicate that using nano clay may increase compressive strength, flexural strength and tensile strength and reduce water penetration and absorption percentage. The best mix design belongs to replacement of 1wt% nano clay. Under water curing conditions in this mix design, rates of compressive strength (35%), flexural strength (31%) and tensile strength (34%) versus control specimen increased, while penetration (35%) and absorption percent (54%) were reduced. The mechanism, nano clay, therefore increases strength and durability in concrete in such a way that the existing Al2SiO5 in nano clay may involve in hydration process and reduce large crystals Ca(OH)2 and accelerate C–S–H gel formation. As a result, dense C–S–H gel is produced and cement mortar and paste will have a more compressed structure. Following the increase in quantity of nano clay up to 2wt% and 3wt%, it is added to the rates of compressive and flexural strengths versus control sample, but in nano clay specimen (1wt%), compressive and flexural and tensile strengths are reduced while water penetration and absorption percentage are increased. It was characterized by analysis on curing methods that showed water curing method was followed by higher strength and durability than in plastic cover curing technique.
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