ASSESSMENT OF VOLCANIC ROCKS, IN EAST JEDDAH - SAUDI ARABIA, AS AGGREGATES

This paper aims at evaluating some Saudi volcanic rocks, 30 km to the east of Jeddah city, as pavement and concrete aggregates. A series of standard tests were implemented. This included; Absorption Index, Abrasion Resistance, Deleterious Materials, Specific Gravity, Gradation, Soundness, Particle shape and Surface Texture, in addition to moisture content and Fineness modulus. Geological investigation results showed that the area contains two main formations: Quartz Diorite + diorite formation and Monzogranite formation. The sample picked from Quartz Diorite + diorite formation was named in this paper "Black Sample". The sample named in this study "white sample" was selected from Monzogranite formation. Results of the standard tests depicted that both black and white samples have different characteristics especially concerning abrasion resistance. Comparing the obtained results with standard specifications showed that both samples can produce aggregates that are suitable for pavement but only black sample can produce concrete aggregates. It was also found that there should be a technical control in the crushing circuit to produce the required gradation.