EXPLORATORY STUDY OF COCONUT SHELL AS COARSE AGGREGATE IN CONCRETE

Abdulfatah Abubakar and Muhammed Saleh Abubakar

Department of Civil Engineering

Kaduna Polytechnic, Kaduna

ABSTRACT

This work is about exploratory study of coconut shell as coarse aggregate in concrete. The approach adopted is experimental to determine the suitability of coconut shell as full replacement for coarse aggregate in concrete works. Physical and mechanical properties of coconut shell and crushed granite rock were determined and compared. A total of 72 concrete cubes of size 150x150x150mm with different mix ratios of 1:2:4, 1:1^1/2 :3 and 1:3:6 were casted, tested and their physical and mechanical properties determined. Aggregate crushing value (ACV) for coarse aggregate is 21.84 and 4.71 for coconut shell. Elongation and flakiness index are 58.54 and 15.69 respectively for gravels, while for coconut shell is 50.56 and 99.19 respectively. Compressive strength in N/mm² of coconut shell at 7,14,21 and 28 days with mix ratios of  1:2:4, 1:1^1/2:3, and 1:3:6 are (8.6, 8.9,6.4,),(9.6,11.2,8.7),(13.6,13.1,10.7) and (15.1,16,5,11) respectively, likewise (19.1,18.5,9.6), (22.5, 23.0, 10.4), (26.7, 24.9, 12.9) and (28.1, 30.0, 15) respectively for gravel. Since the concrete strength of coconut shell with mix ratio 1:1^1/2:3, attained 16.5N/mm² at 28 days it can be used in plain concrete. Hence cost reduction of 48% will be achieved.