Experimental Study on Effects of Casting Procedures on Compressive Strength, Water Permeability, and Interfacial Transition Zone Porosity of Rock-Filled Concrete

Abstract

This study investigated the effects of different casting procedures on compressive strength, water permeability, and interfacial transition zone (ITZ) porosity of rock-filled concrete (RFC). Mixes of concrete with the same proportions were cast using the self-compacting method (the casting procedure of RFC) and the vibration method (the casting procedure of normal concrete). A control group of concrete was prepared to reveal the effects of aggregate size. Compressive tests and water permeability tests were performed in accordance with the current codes. Scanning electron microscopy was used to calculate the porosity of the ITZ by processing the second electron and backscattered electron images of the ITZ. The findings indicate that the self-compacting method can improve compressive strength and particularly impermeability grade. Switching the vibration method to the self-compacting method also significantly reduces ITZ porosity, especially the ITZ porosity at the lateral surface of the aggregate.