عنوان مقاله [English]
The idea of using paper wastes in concrete to reduce environmental pollution and the use of Silica fume to improve the properties of concrete is a huge transformation in the building industry. In this study, the effect of waste paper ash along with silica fume on mechanical properties of concrete was investigated experimentally. The cement was replaced with different percentages of paper waste ash (0, 2.5, 5, 7.5 and 10%) and Silica fume (0, 2.5, 5, 7.5 and 10%). 25 mix designs were prepared. Compressive strength, indirect tensile strength, flexural tensile strength, slump, ultrasonic pulse velocity, impact tests are performed for all concrete specimens at different ages. Also, Creep, have been presented for concrete containing waste paper ash and silica fume based on existing equations and were compared with the concrete code of USA and concrete code of Iran. This equations are suggested to predict the behavior of concrete containing waste paper ash and silica fume. It is also observed that in a constant water cement ratio, and for all ages, increase in Silica fume and paper waste ash. Also, based on the results of this study, empirical relationships have been presented for the relationship of indirect tensile strength and 28-days compressive strength of concrete, tensile strength due to flexural and 28-days compressive strength of concrete specimens, compressive strength and specific weight.So that these equations can be used to predict the behavior of concrete containing the paper waste ash and Silica fume. The tensile strength/compressive strength ratio of ordinary concrete is about 10. However, this ratio is between 13.55 and 17.79 in concrete specimens containing waste paper ash and silica fume. The compressive strength ratio of 28 days to 90 days is between 0.67 and 0.81. However, this ratio is between 0.55 and 0.65 in ordinary concrete, which indicates a higher initial strength in specimens containing waste paper ash and silica fume.