Using different types of fine aggregate to produce high strength concrete

الملخص EN

High-strength concrete (HSC) has undergone many developments based on the studies of influence of cement type, type and proportions of mineral admixtures, type of super plasticizer and the mineralogical composition of coarse aggregates.

Most studies were carried out using natural sand with rounded and smooth grains.

In practice, fine sands from various sources are frequently used in concrete.

In this paper, two aspects of the effect of fine aggregate on HSCs are presented.

First, the performance of fine sands in relation to natural sand using a low water / cement (w / c) ratio and fixed coarse aggregate and cement content is analyzed.

Results show that concrete with fine sand requires an increase of super plasticizer to obtain the same slump.

It also presents a higher strength than the corresponding natural sand concrete at all test ages, while its elastic modulus is lower at 28 days and is the same after that.

Studies on the development of hydration and mortar phase of concrete show that the increase of strength can be attributed to the improvement of paste–fine aggregate transition zone.

Second, the influence of the mineralogical source of the crushed sands was studied using three different types of crushed sands (limestone, granite and steel slag) with similar grading.

Two mixtures containing 450 and 485 kg / m3 cement and low w / c ratio are analyzed.

Results show the adverse effects of shape and texture on workability of concrete, but the compressive strength of concrete is improved.

Granite and steel slug crushed sand appears as the most advantageous sand for this purpose.