Effects of Calcium Carbonate Nanoparticles and Fly Ash on Mechanical and Permeability Properties of Concrete

Abstract

Abstract The use of additives to supplement or replace cement in concrete is a well-studied topic. The use of fibers, polymers, minerals, and even nanomaterials has been considered for improving concrete properties such as permeability and strength, and these issues are constantly under investigation. In this study, the mechanical properties and permeability of concrete containing calcium carbonate (CaCO3) nanoparticles and fly ash are investigated. For this purpose, concrete specimens with different proportions of nanoparticles and fly ash were prepared and aged for 7 days and 28 days to investigate the mechanical properties via compressive strength tests, tensile strength tests, and flexural strength tests under three-point loading and also to study the permeability properties via full water absorption tests and the testing of penetration depth under water pressure. To determine the distribution of nanoparticles and their size and microstructure, scanning electron microscopy (SEM) images were obtained, and energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses were performed. The results show the positive effect of CaCO3 nanoparticles in filling concrete pores, which leads to increased strength and reduced permeability. In general, the SEM images and EDS and XRD analyses showed that there was a good correlation between the materials used in the concrete and also that the nanoparticles were appropriately distributed in the concrete samples.