Feasibility Study on Concrete Dust as a Substitute of Filling Sand for Road Construction

Abstract

Affiliated with the increase of construction and demolition of the structural projects in the whole world along with Bangladesh, the country is producing a whale of Construction and Demolition (C and D) waste every year. But the colossal anxiety is that these huge amounts of C and D wastes are not managed well. Besides, sand mining is at its peak in Bangladesh because of the demand in the market. The effect of sand mining is the reason for many adverse effects on the ecology of the river including degrading the water quality of the river, changing the physical quality of the river, decreasing the river flow, riverbank erosion, and riverbank slump. That’s why Recycled Fine Aggregate (RFA) can be the future in the construction industry. But this study mainly focuses on using RFA as a substitute for the filling sand as well as an alternate of Improved Subgrade (ISG). For this purpose, demolished concrete blocks were collected and turned into RFA to evaluate their engineering properties. In this study properties of tested RFA are compared with locally available sand or filling sand. Hence, after evaluating the properties of the tested material, it is established that the value of Fineness Modulus (FM) is 2.074, Maximum Dry Density (MDD) is 1.617 gm/cc, Plasticity Index (PI) is 4.12 and California Bearing Ratio (CBR) is ranged from 4.809 to 15.022 and the attained values of respective properties are in the range of sandy soil and come out well than the filling sand. But the Optimum Moisture Content (OMC) rate is 21.14% which is higher than the sandy soil and determined Specific Gravity (GS) is 2.57 which turns out to be lower than the average sandy soil but in the range of filling sand. Other Engineering Property like Permeability (K) is determined 1.503*10-4 of the tested soil sample which is also comparatively adequate.