EVALUATION OF COMMONLY USED AGGREGATES FOR SUSTAINABLE INFRASTRUCTURE DEVELOPMENT IN BANGLADESH

A good number of infrastructure projects are implemented in Bangladesh during the last decade and many more are still in pipeline. In the financial year 2017-18 approximately 12.7 million tons of aggregate are used by the construction industries. Local sources could supply only 11% of those aggregate and rest 89% are collected from foreign sources. Due to the wide variation of aggregate sources performance of concrete become unpredictable. Therefore, in the present study influence of commonly used coarse aggregate characteristics for building sustainable infrastructure are investigated by evaluating the performance of concrete with various aggregate types. To evaluate performance, six mostly used coarse aggregate sources are selected for this study. A series of laboratory test are conducted to evaluate the ACV, TFV, LAA, EI, FI, specific gravity, water absorption and unit weight for all six aggregates. Additionally, chemical composition and petrographic properties are also explored. Keeping the gradation of aggregate constant, two types of concrete mix (w/c ratio 0.3 and 0.4) were prepared to cast concrete cylinders and beams by using six sources of coarse aggregate. Concrete properties including compressive, tensile and flexural strength are determined. The study finds that physical properties of aggregate generally influence the properties of concrete. However, the influence is significant in case of concrete requiring compressive strength higher than 50 MPa. The outcomes of the study will help the engineers to select appropriate sources of aggregate depending on concrete strength requirements.