AGGREGATE-CEMENT PASTE INTERFACE - II - INFLUENCE OF AGGREGATE PHYSICAL-PROPERTIES

This paper describes part of a large project on aggregate-cement inter actions and interface bonding mechanisms in concrete. This part of the study investigates the influence of aggregate physical properties on the nature of aggregate-cement paste interfacial bonding with the aim of establishing the bonding mechanisms as controlled by a,aggregate ph ysical properties. A newly developed experimental technique to charact erise quantitatively the aggregate surface texture using a surface pro filometer is also presented. Three commonly used concrete aggregate ro cks (basalt, limestone, and quartzite) were investigated. Significant differences in the measured bond strength and modes of failure of rock -hardened cement paste composite specimens under uniaxial tension were observed between the different rock types. Based on the results prese nted, it is apparent that for a given cement paste, the interfacial bo nd strength cannot be predicted from aggregate surface roughness alone . (C) 1998 Elsevier Science Ltd.