Recycled Aggregate Concrete with Fluorescent Waste Glass and Coal/Wood Ash Concrete Wastes

Concrete as a primary building construction material is the most consumed man-made material in the world and also is one of the most consuming landfills waste materials. Production of cement (hydraulic binder) is an energy-intensive and highly polluting process which contributes about 5-8% to global CO2 emissions and accounts for 3% of total (5% of industrial) energy consumption worldwide. The aggregates constitute approximately 80% of concrete volume. The disposal of the construction and demolition (C&D) waste is becoming increasingly difficult and expensive and also environmental concerns are increasingly limiting the option of landfilling such waste. Recycled aggregate is a valuable resource; value-added consumption of recycled aggregate, as replacement for virgin aggregate in concrete, can yield significant energy and environmental benefits. Glass is also one of the most popular materials due to progressive growth of urbanization nowadays. Disposal of glass waste and especially of non-recycled waste glass is a complex problem for many countries in the world. Waste glass as powder milled to certain surface specific area in order to accelerate beneficial chemical reactions in concrete offers desired chemical composition and reactivity for use it as a supplementary cementitious material (SCM) for enhancing the chemical stability, pore system characteristics, moisture resistance and durability of concrete. The beneficial effects of milled waste glass can enhance the residual cement occurring on the surface of recycled aggregates, thus improving the performance characteristics of recycled aggregate concrete (Nassar and Soroushian, 2012). In present study is investigated the approach of optimized utilization of concrete aggregate wastes (CAW) in concrete. An experimental study was carried out to investigate the effects on the mechanical properties of concrete with CAW obtained from crushed concrete specimens (from previous studies with cement substitution at level of 30% with waste borosilicate (DRL) glass chippings obtained from fluorescent lamps and ground into powder with specific surface area of 2310 cm2/g, waste glass suspension and coal/wood ashes (Kara, 2012)) after they have been stored as concrete waste. A total of 15 different concrete mixes were prepared. Concrete cubes’ strength tests were carried out after 7, 28, 56, 84 and 112 days. Three sets of experiments were hold (substitution of natural aggregates at level of 100%, 50% and 50% +plasticizer). Recycled aggregates from concrete specimens with known mix composition have performed good mechanical strength results in comparison to control ones. The best obtained result was for the mixes with wood ash 68 MPa and waste fluorescent glass suspension CAW of 74 MPa.