Influence of artificial aggregate on mechanical properties, fracture parameters and bond strength of concretes

Abstract

The paper presented herein investigates the mechanical performance of concrete involving lightweight and normal weight aggregates with similar compressive strength. For this, two compressive strength values, 25 and 45 MPa, were considered for the concretes produced by normal and lightweight aggregates. Therefore, four concrete mixtures were designed at different water-to-cement ratios and cement contents. The lightweight aggregate utilized in this study was produced through cold bonding pelletization of fly ash and cement at ambient temperature in a specially designed tilted pan. The artificial lightweight aggregate used as a substitution of natural aggregate had similar particle size distribution to that of natural aggregate. The same mixing procedure was adopted to produce concrete and the testing specimens attained from each mixture were cured at the same circumstances. After the 28-day curing period, the specimens were tested for compressive strength and modulus of elasticity, splitting tensile and flexural strengths. Moreover, advanced mechanical properties such as fracture parameters, bond strength between embedded reinforcement and the concrete were also investigated. The test results indicated that it is possible to produce the lightweight aggregate concrete having similar compressive strength with the natural aggregate concrete, however, the utilization of artificial lightweight aggregates significantly influenced the investigated mechanical and fracture properties of the concretes despite having the similar compressive strengths. But, it was also observed that the utilization of lightweight aggregate made the concrete more ductile.