EFFECT OF COARSE AGGREGATE ON FRACTURE OF CONCRETE : Part 1 : Model Analysis

Tensile and shear bond strength between cement paste and aggregate subjected to high temperature

“…According to Taylor and Broms [17] and Gu et al [22], this friction angle corresponds to a failure mode by slip at the interface rather than crushing of the paste. In order to examine the effect of the strength and surface condition of coarse aggregate on the fracture of concrete, Kosaka et al [19] performed shear bond test on specimens consisted of a cylindrical coarse aggregate and mortar matrix. They showed that shear bond strength depends on the curing condition, type of aggregate and surface roughness.…”

“…It has to be kept in mind that it is just a model interfacial system that allows producing a bond between matrix and aggregate. In fact, the material preparation (mixing) greatly affects the formation of ITZ in concrete [14][15][16][17][18][19][20][21][22][23][24][25][26]. Pope and Jennings [26] reported that the interfacial zone of a limestone mortar is reduced in size by controlling the water-aggregate contact through a pre-coating procedure or by mixing the cement paste separately.…”

“…The nano-indentation technique, which is potentially the only one able to directly evaluate the mechanical properties of the interface, has its limitations due the great variability of the measurements [14,15]. That is why different authors have thus tried to perform tests with simplified models such as sandwiched specimens in which cement paste (or mortar) is in contact with coarse aggregate [16][17][18][19][20][21][22][23][24][25]. It has to be kept in mind that it is just a model interfacial system that allows producing a bond between matrix and aggregate.…”

Mesoscale Simulation of Influence of Frost Damage on Mechanical Properties of Concrete

“…Shear stress is proportional to shear strain until it reaches a maximum value ( max ) and then remains constant at  max as shear strain rises further. The  max criterion for mortar was developed by the authors, while the one for interfaces was based on the failure criterion suggested by Taylor and Broms (1964) and Kosaka et al (1975) as follows:…”

“…In fact, some of the properties in Table 1 are not independent but affect each other. The method proposed by Nagai et al (2004), based on experiments conducted by Hsu and Slate (1963), Taylor and Broms (1964), Kosaka et al (1975) and Yoshimoto et al (1983), was used for the relationship between the material properties. The material parameters in Table 1 were chosen such that the compressive strength of undamaged concrete was near to the experimental value of 49.8 MPa (Hasan et al 2004).…”