The effects of type of cement and curing methods on the pore structure of concrete

摘要

The resistance of cementitious materials to chemical attack or physical degradation is related to the mechanical properties of the material, but more importantly the chemical and microstructural characteristics and particularly the pore structure of the hardened material. Given information about pore structure, Mercury Intrusion Porosimetry (MIP) is a technique that can provide such information which has improved significantly in pressuring capacity and in operational convenience. By measuring the amount of mercury intruded into the pores of a solid sample, the porosimeters give valuable data from which cumulative volume and pore size distribution, porosity as well as pore surface area can be determined. In this work, five concrete mixtures are prepared with water/cementitious material ratio 0.4 to investigate the effect of using different types of supplementary cementing materials and curing methods on the pore structure of concrete. The measured properties of fresh concrete include slump, air content and unit weight while the measured properties of hardened concrete include compressive strength, flexural strength, tensile strength, pulse velocity and dynamic young's modulus as well as the pore structure characteristics which involve, porosity, cumulative intrusion volume, pore surface area, and pore size distribution. These properties are measured according to the specifications provided by Japanese Industrial Standard (JIS) after 28 days of curing.