EVALUATION OF COMMONLY USED AGGREGATES FOR SUSTAINABLE INFRASTRUCTURE DEVELOPMENT IN BANGLADESH

Abstract

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.