PETROGRAPHIC EVALUATION AND PHYSICO-MECHANICAL PROPOERTIES OF CONCRETE MADE WITH DIFFERENT KINDS OF NATURAL AGGREGATES

Abstract

Dolomite, basalt, and granite coarse aggregates samples were collected from stockpiles of operating aggregate quarries (Wadi Abu-Saiyala dolomite, Widan El-Faras basalt, and Homra El-Girigab granite quarries) for assessment based on their physical, chemical, mechanical, mineralogical, and petrographic properties. Moreover, the assessment of sand as a fine aggregate is based on their physical and chemical properties. The bulk density values of coarse aggregate (dolomite, basalt, and granite) in compacted mode are in the range of normal weight concrete aggregates. The water absorption values and the grading curves of dolomite, basalt, and granite aggregates are in the permissible limit specified of specification. The percent of material finer than 75 µm (fine materials) of dolomite, basalt, and granite aggregates are in the permissible limit of specification. However, dolomite aggregates show the highest content of fine materials. The bulk density of the fine aggregate (sand) in the compacted mode lies within the range of normal weight concrete aggregates. The water absorption of sand is below the permissible limit of specification. Also, the percent of material finer than 75 µm in sand is below the permissible limit. The soundness, soluble chlorides, and sulphates content in dolomite, basalt, and granite aggregates are all within the limits of specifications. The content of soluble chlorides and sulphates present in the studied sand are below the limits of specifications The alkali expansion values of the examined concrete prisms made with dolomite and granite aggregates are below the limit of specifications (uncreative aggregates). Whereas, concrete prisms made with basalt aggregates expansion value are above the limit (reactive aggregate). It could be concluded that the investigated basalt aggregates could be used in concrete with much precautions in large scale patches, due to presence of alteration products in basalt. Based on the mechanical property test, the Los Anglos abrasion values for dolomite and basalt aggregates are within the specified limit (high resistant to abrasion). On the contrary, the Los Anglos value of granite aggregate is out of limit (least resistant to abrasion). The X-ray diffraction analysis of the investigated dolomite aggregates revealed that the studied samples are classified as calcitic dolomite, with no free silica (Quartz), non-carbonate