Effects of coarse aggregate morphology on performance of cement-based materials under cyclic loadings Conference

cited authors

  • Lee, SJ; Lee, C; Shin, M; Bhattacharya, S

fiu authors

abstract

  • This paper investigates the effects of coarse aggregate morphology on mechanical properties of cement-based materials. In order to ensure structural integrity and prolong the serviceability of aging infrastructure against man-made/natural hazards including earthquake, the civil engineering community has been trying to improve the mechanical properties of cement-based materials, e.g. high performance concrete, confined concrete, with enhanced predictive capability of the behavior. However, there is still a gap to fill in the body of knowledge; the effects of aggregate morphology on the performance of cement-based materials. The influences of the particle size distribution and the maximum nominal size of aggregates have been studied in depth. However, the effects of aggregate morphology have not been clearly understood, since research efforts have been hindered or the success has been limited due to high uncertainties in characterizing the 3D aggregate morphology and their distribution. The concrete industry has witnessed the importance of understanding the grain-scale aggregate morphology to estimate the macroscopic mechanical performance. For example, the use of highly angular aggregate results in a higher strength of concrete due to enhanced interlocking. The challenges for systematic study and questions on mechanical properties such as modulus, residual strain influenced by the morphology still remain to be better answered. This study introduces a systematic approach that quantifies 1) the 3D aggregate morphology and their distribution using a set of global form and local angularity values, and 2) its relations to the mechanical properties of cement-based materials under cyclic loadings. Two different sets of coarse aggregates are prepared: a) crushed and b) river (round) aggregates of which angularity can be clearly distinguished in terms of the morphology indices herein. A digital image analysis of each aggregate morphology is performed. Cylinders with two different sets of the aggregates are prepared and tested under cyclic loadings.

publication date

  • January 1, 2018

start page

  • 5410

end page

  • 5420

volume

  • 9