Efficiency of natural gravel application in heavyweight concrete

Abstract

Introduction. The shortage and high cost of granite crushed stone stimulate the search for more affordable aggregates for heavy concrete. This paper presents the results of a laboratory study aimed at comparing the properties of heavy concrete prepared using two types of coarse aggregate granite crushed stone and natural gravel of 5–20 mm fraction.

Aim. Substantiation of the technical and economic feasibility of replacing granite crushed stone with natural gravel in heavy concrete, provided that the strength characteristics are not lower than the required ones. Materials and methods. The main attention is paid to the influence of the shape and surface texture of aggregate particles on the water demand, strength, and cost of the concrete mixture under the same workability (slump class S5).

Results. It was found that the use of gravel instead of crushed stone reduces water demand [1], which leads to a decrease in the water-cement ratio and, consequently, to an increase in strength. In the case considered in this article, concrete with gravel achieved class B20, while its counterpart with crushed stone achieved only class B15. An economic calculation showed a cost reduction of 7.8 % when replacing crushed stone with gravel. 

Conclusions. The experimental results indicate that, with proper mix design, gravel can be not only a cost-effective but also a technically preferable alternative to crushed stone in the production of heavy concrete.