CO2 EMISSION ASSESSMENT FOR RICE HUSK ASH IN CONCRETE ON ENVIRONMENTAL APPROACH

Resumen

The construction industry causes significant negative environmental impact, partly due to the vast amounts of building materials used, and rice husk ash (RHA) is a solid waste produced in thermal power stations with potential applications as a partial replacement to Portland cement. Due to the increasing demand for research on environmental issues, the life-cycle approach emerges as an important tool in such investigations. This study evaluates the environmental performance of RHA as a replacement material for cement during the life-cycle of concrete. Environmental aspects and impacts associated with the combustion of rice husk biomass in a grate furnace and in a fluidized bed reactor, the transportation of the RHA produced, and its use in concrete production were evaluated. The most significant environmental impact caused by RHA production processes was global warming potential. The replacement of 20% Portland cement by RHA produced by combustion on fluidized bed reduced CO_2eq emissions by 24%. Even though this ash type had to be transported for 400 km to its destination, its use remained environmentally advantageous. But the replacement of 20% Portland cement by RHA produced by combustion on a grate furnace led to a reduction of only 7.7% in CO_2eq emissions.