الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In recent years, the demand for structural lightweight concrete increased at many applications of modern constructions. This type owns many advantages such as lower density results in a significant benefit in terms of load-bearing elements of smaller cross sections and reduction in the size of the foundations. The aggregates considered the former of concrete, which is, actuates about 75% of concrete volume. Using lightweight aggregate (LWA) in the concrete industry contributes to producing the lightweight aggregate concrete (LWAC). Lightweight aggregate (LWA) are broadly classified into two types; natural (such as Pumic, Diatomite, volcanic, cinders, etc.) and artificial (perlite, expanded shale, clay, slate. Lightweight concrete (LWC) has been successfully used since the ancient Roman times. It has gained its popularity due to its lower density and superior thermal insulation properties. (LWC) can significantly reduce a dead load of structural concrete elements compared to normal weight concrete. Concrete cast using recycled aggregates considered as green concretes as their positive impact on the environment. This research conducted to study the efficiency of obtaining structural (LWC) cast using recycled aggregates as coarse aggregates. In this research, the main variables are; type of recycled coarse aggregates used (crushed light brick, crushed glass, and crushed red brick compared to dolomite), the dosage of lightweight aggregate used (Foam” as 0, 10, 20 and 30% of coarse aggregate volume). The investigated physical properties included the unit weight and slump values as well as the main mechanical properties of hardened concrete in terms of compressive, tensile, flexural, and bond strengths. For lightweight concrete with dolomite and all recycled aggregates, the optimum foam dosage is 10% (as a ratio of coarse aggregate volume).
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The strength of the lightweight concrete with dolomite aggregates is higher than lightweight concretes with crushed light brick, crushed glass and crushed red bricks as recycled aggregates.
Using lightweight brick is more efficient to produce lightweight concrete while using dolomite is more efficient to produce structural concrete. Generally using crushed glass is most advisable to obtain lightweight concrete with sufficient properties.