Lime-stabilized solid-waste blends as alternative building blocks in construction

Stabilized blocks have been gaining ground in recent times. Stabilized solid waste blocks provide an eco-friendly alternative to conventional fired bricks. The present investigation dealt with the development of lime stabilized blended solid waste blocks comprising fly ash (FA), steel slag (SS) and phosphogypsum (PG). The PG content was limited to 10% and the proportion of FA:SS was varied in the remaining 90% in the ratios of 1:2, 1:1 and 2:1. The blends were stabilized using 2%, 4% and 6% lime. The blends were dry mixed, followed by the addition of a sufficient quantity of water to obtain a uniform wet mix. This mix was then packed into moulds to cast blocks. The blocks were demoulded after 24 hours under wet gunny bags and cured in water for 7 days. Similarly, the blends were also mixed with sand to prepare solid waste mortars blocks and cured for 7 days. At the end of their stipulated curing periods, the stabilized solid waste blocks and mortar blocks were tested for their compressive strength. The results of the investigation revealed that the mix LFSP621 developed the maximum strength of all combinations tested and hence, it can be concluded that the solid waste blend consisting of 60% FA, 30% SS and 10% PG stabilized with a further 6% lime by weight of the solid waste mix was the most optimal mix for developing maximum strength of the solid waste blocks. The mortar blocks, however, met with limited success. Thus, it can be concluded that stabilized solid waste blocks can become an effective alternative building material.