Recycle of construction waste rubbles in urban transformation process

Turkey is an earthquake country that is situated on two main fault zone called North Anatolian (NAF) and East Anatolian (EAF) Fault. But, it is clear that most of structures do not have the technical requirements which must be had against natural disasters such as earthquake. However, unregistered life increased day by day as a result of illegal housing. This situation precipitated illegalities and made inspection harder. Therefore, illegal housing areas and structures completed economic life need to be re-designed by providing all urban and social service requirements and taking all natural disaster risks away across the country. In this respect, urban transformation operations have started on 5th October 2012 within the scope of the law that stipulates transforming areas under disaster risks on all over the country. It is foreseen that 6.5 million of dwellings will be demolished and rebuilt during the project that is planned to take 20 years. It is clear that urban transformation project will place a burden to nature beside pure, comfortable and safe life. It is predicted more than 4-5 million tons of construction & demolition waste (C&D waste) will emerge yearly and disposing these C&D wastes is considered as a crucial environmental issue. To send wastes directly to the landfills will cause devastation of huge natural areas. However, efficient and recyclable use of natural sources as one of main factors for sustainable development is crucial for developing countries such as Turkey. In substance, landfill inadequacy must be taken into account and it must not be forgotten that disposing these wastes will place a burden to country economy. Thus, waste rubbles must be reutilized by means of recycling in consideration of both economical and environmental reasons. It is necessary to create public awareness and make detailed researches about reusability of rubbles in order to popularize use of C&D wastes. For that reason, main subject of the study is use of recycled aggregates derived from rubbles in new concrete manufacture. In scope of this study that researches reusability of construction rubbles as coarse aggregate in new concrete manufacture during the urban transformation process, physical and mechanical properties of manufactured concretes are investigated. Natural coarse aggregates in mixtures (grain sizes of 4/16 and 8/32) are replaced by recycled aggregates that have same granulometry. In this manner, 25%, 30% and 55% of aggregates in mixtures were provided to be recycled aggregate. Besides combinations which are generated by means of replacing natural aggregates by recycled aggregates, volume of 0%, 1% and 1.5% polypropylene fibers were experienced for each mixture. Fresh and hardened concrete experiments were carried out on manufactured concretes. All hardened concrete experiments (physical and mechanical) were performed on the day of 28 after casting. Experiments of sieve analysis, specific gravity, moisture content, water absorption, Los Angeles abrasion and organic matter content are carried out on aggregates which will be used in mixtures before manufactures. Collapse slump, unit weight, air void content as fresh concrete experiments; unit weight, water penetration depth under pressure, ultrasonic pulse velocity, compressive strength, splitting tensile strength, static&dynamic modulus of elasticity and flexural tensile strength experiments were carried out as hardened concrete experiments and fracture toughness' were calculated in order to compare the concretes that have same mixture ratios with natural aggregate and recycled aggregates. According to experimental results, it is seen that recycled aggregates have higher water absorption capacity, lower specific gravity and abrasion resistance than natural aggregates. Besides, it is observed that recycled aggregates might influence concrete's physical and mechanical properties a bit negatively but fiber content improved flexural and splitting tensile strength properties generally.