ABSTRACT
Abstract This study was carried out striving at gaining a lucid understanding of the effects of interfacial zones and surface conditions (roughness) of aggregates on the strength of specimens. For this purpose, two dimensional model specimens measuring 100 x 200 x 40 mm were prepared using cement-sand mortar, containing cylindrical steel aggregates. The steel cylinders, which is stronger than the mortar matrix and do not absorb water, were given smooth as well as grooved surfaces, to simulate varying surface conditions. Test results show that addition of small numbers of aggregates into the specimen has a detrimental effect upon specimen strengths. The strength decreases from 70 MPa at specimens with no inclusions to 34 MPa at specimens with 6 smooth surfaced inclusions and regains strength at higher inclusion numbers. Results also indicate that specimens containing rough surfaced inclusions consistently provide higher strength than specimens with smooth surfaced inclusions. At the lowest point, the use of rough surfaced aggregates in the specimen increases its strength by approximately 35 %. Test results are compared against FEM analyses. Keywords: Concrete model, crushing strength, cylindrical steel inclusion, grooved surfaces, interfacial zones, metal aggregates, model specimen, non-linear stress analysis.
