Evaluating the use of steel scrap, waste tiles, waste paving blocks and silica fume in flexural behavior of concrete

摘要

Steel scrap is a waste product of steel plate manufacturing industry. A large quantity of steel scrap is produced by drilling every year. The disposal of those steel scraps is a major issue in Iraq and all over the world. The landfill is one of the methods for disposing the scraps albeit it produces soil pollution. What is worse is that in Iraq there is no waste separation system in a sense that all the waste materials are dumped in soil especially in the desert, and it is harmful to the environment. One way to alleviate the situation, the present study suggests that steel scrap is added with concrete, and the mechanical and physical properties were studied. Waste materials, such as terrazzo tile and paving block, are dumped in landfills. Such action destroys the environment. Recycling these materials and using them as fine and coarse aggregate in new concrete mixes would eliminate the problem. Additionally, these waste materials are considered as non-degradable. Silica fume has been employed as a partial replacement by weight of cement at percentages of (8%, 12%, and 16%) to enhance the concrete that contains the waste materials. This paper examines the workability of addition of steel scrap to the weight of concrete by the percentages of (0.6%, 1.2%, and 1.8%) as well as the addition of porous tile and paving block as partial substitute by percentages of (15%, 30%, and 45%) for coarse and fine aggregate, respectively. Concrete samples were produced and subjected to compression strength, water absorption and split tensile tests. A reduction in strength was observed for all concretes that contain porous tiles waste as the percentage increased, in relation to the control concrete. On the other hand, concrete that contains waste paving blocks shows an increment in strength at the percentages of (15% and 30%) and reduction at the percentage of 45%. Based on the compressive strength test results, steel scrap samples being at 0.6%, 1.2%, and 1.8% show that the strength increased of the samples with 0.6% and decreased of those at 1.2% and 1.8%. Thus, this research demonstrates that the use of three waste materials-crushed tiles waste, steel scraps and paving blocks waste as components of concrete is technically feasible in the manufacture of concrete.