Title:
Three-Dimensional Aggregate Density in Concrete with Wall Effect
Author(s):
Jian Jun Zheng and Chun Qing Li
Publication:
Materials Journal
Volume:
99
Issue:
6
Appears on pages(s):
568-575
Keywords:
aggregate; concrete; density
DOI:
10.14359/12366
Date:
11/1/2002
Abstract:
In view of the importance of aggregate density to the mechanical properties of concrete, it is necessary to determine the aggregate density at any point in concrete. Once the aggregate density is known, some mechanical properties of the concrete can be determined based on the theory of micromechanics. This paper presents a simulation algorithm for the three-dimensional distribution of aggregate particles within a concrete element. The intention of the paper is to develop a model of aggregate density in concrete, taking into account the effect of formwork walls. Based on the simulation results, the characteristics of aggregate distribution in boundary layers of a concrete element are investigated and the statistics of the developed model of aggregate density are derived. It is shown in the paper that the mean value of aggregate density at any point in the concrete element converges asymptotically to a constant when the number of simulations tends to infinity. Using mathematical regression, the aggregate density as a function of distance from the boundary and the thickness of the boundary layers can be expressed analytically in terms of the aggregate volume fraction of the concrete. Also presented in the paper is the experimental verification of the cumulative distribution function of aggregates used in the simulation and the developed model of aggregate density.