Assessment of Engineering Properties of Al-Haweri Scoria, NW Sana’a, Yemen

Yemen has an appreciable amount of scoria aggregate, but a very small proportion is used as cement additions by local cement factories in blended Portland cement production and very rarely as aggregates into the production of lightweight blocks. Scoria aggregates are widespread in and around the volcanic cones present in Sana’a-Amran volcanic field. This paper presents the results of evaluation of engineering properties of natural scoria, collected from Al-Haweri volcanic cone, NW Sana’a, Yemen as lightweight aggregate. Chemical composition and petrographical characteristics of scoria were determined. The physical properties of the scoria aggregate such as flakiness and elongation indices, specific gravity, water absorption, unit weight, clay lumps and materials finer than 75µm gave acceptable results, but the gradation indicated it would need to be processed before use in a mix. The porosity is high, 60.79%. The Los Angeles abrasion and the aggregate crushing values are higher than the limits of ASTM and BS specification, but the aggregate impact value is close to the upper limits of BS specification. The soundness is within the ASTM specification limits. Therefore, it can be concluded that scoria aggregates can be used to produce structural concrete and masonry blocks with a relatively low density. The scoria aggregates satisfied the requirements of lightweight aggregate for structural concrete and masonry blocks purposes.