Effect of municipal solid waste ash on comprehensive strength characteristics of an interlocking block masonry wall

Abstract

Masonry is a layered composite which consists of mortar and masonry units. A good bond between the units is essential and determines how the masonry transfers and resist stresses due to applied loads. In this study interlocking blocks were used in masonry wall construction in order to introduce uniformity in the wall model by eliminating mortar as a binding media. The blocks were moulded in a CINVA-Ram machine by replacing 0%, 2%, 5% and 10% of municipal solid waste ash (MSW ash) as a stabilizing agent. The compressive strengths of individual blocks were obtained after curing for 7, 14 and 28 days. The 2%MSW ash replacement gave the highest compressive strength and was used in constructing the wall model. The wall models were loaded in compression in direction normal to bed joints. The 2%MSW ash stabilized Juja soil wall failure was generally associated with diagonal cracks and bulging of the wall from sides. A maximum crack width of 40 mm wide occurred at failure with the central deflection of the wall reaching 20 mm at an ultimate failure stress of 2.49 N/mm². The failure mode of un-stabilized Juja soil wall model was mainly due to vertical cracks forming below the load application point. The ultimate failure stress of un-stabilized Juja soil wall was 2.5 N/mm², however its central deflection was low than that of stabilized wall. Conversely, un-stabilized Murang’a soil wall failed by crushing introduced by vertical cracks. A maximum stress of 0.997 N/mm² was achieved with a central deflection of 12 mm. Stabilized Murang’a soil had a low failure stress of 0.85 N/mm² as compared to the un-stabilized soil. The wall failed due to a combination of horizontal and diagonal cracks forming on the wall. In both cases the strength of individual blocks was higher than that achieved in the wall models. The progression of failure stress cracks for 2%MSW ash stabilized wall model was corresponding to that recommended in the code of practice for masonry, thus the same code can be used in design of stabilized masonry walls.

Keywords: Compressive strength, failure mode, interlocking blocks, stabilization, Solid Waste Ash.

Nigerian Journal of Technological Research, 8(2), 2013