Study of the effects of shrinkage on concretes based on pozzolana and perlite

Abstract

Concretes are subjected to several kinds of shrinkage strains which represent the variations in volume, resulting from the composition and the dosage of the cement hydration, and are governed by various physical and chemical aspects. The use of perlite (PER) and natural pozzolan (PZN), which are available in large quantities and with low cost in our country, yields a very important economic and environmental impact to the construction industry. We are interested in investigating the effect of PER and PZN in variation volumes due to the shrinkage of concretes. The aim of this work is to study the effect of Maghnia perlite incorporation, in comparison and in association with the PZN of the Beni-Saf region, on the evolution of the deformations (shrinkage: endogenous and exogenous shrinkage) of concretes at substitution rates ranging from 10 to 20 and 30%. In parallel, a comparison will be made to see the mineral effect on the composition of concrete. Separate quantification of the endogenous and exogenous shrinkage showed the effective contribution of each addition to the microstructure modifier and the production of additional hydrates. The microstructure has proved the presence of perlite in comparison with the study of the obtained experimental results with the prediction of deformation of shrinkage according to Eurocode2 (EC2). This was done to analyze the evolution of shrinkage strain with PER and PZN-concrete composite ages with several rates of PER and PZN additions. According to the obtained results, PER and PZN additions act to reduce the shrinkage strains of PER and PZN-concrete composites which promote the use of these modified concrete eco-materials in the field of the construction industry.