Use of Industrial Sludge as an Ingredient in Making of Bricks

Abstract

Bricks are the building block of the construction industry. Land mining to extract earthen clay is slowly turning uneconomical and problematic in accommodating its land use while already a huge demand for land exists for other needs such as residential, commercial and more. Another major concern associated with land mining is the loss of fertile soil that has to be plowed in order to obtain the clay earth. This demand for finding alternatives for brick manufacturing and usage of waste is the best possible solution. Sludge, a solid or semi-solid extract is obtained from the waste treatment plants. The amount of sludge generated and its environmental friendly disposal is a problem of concern. The conventional practice of landfilling or discharging into streams is no longer a solution for the scarcity of land and hazardous environmental effects. Bringing together both the concerns on a single platform, a feasible and eco-friendly solution is Green Brick. In this paper, four types of green bricks of size (19cm x 9cm x 9cm) were manufactured using sludge-clay mix with the proportion of sludge varying from 10% to 30%. These samples were tested as per Indian Standards for efflorescence, hardness, water absorption and crushing strength and the results compared to that of standard clay brick. Amongst all, Type B (having 15%sludge) showed the most favorable results with a crushing strength of 7.10 N/mm2 and 17.22% of water absorption. Though Type A brick (having 10% sludge) had the comparable crushing strength of 7.89 N/mm2 but showed highest water absorption of 18.73%, Type B brick is considered most superior amongst all and falls in the second class category as per Indian Standards.