Captura de CO2 em blocos de concreto por meio da cura carbônica e aplicabilidade industrial

Abstract

To minimize the effects of global warming, global CO2 emissions should be reduced by 45% by the year 2030. If nothing is done, by 2100 the concentration of CO2 in the atmosphere should increase by 41 to 158% compared to current levels, reaching values ranging from 535 to 985 ppm. In this scenario, the cement industry, responsible for up to 8% of global emissions, can contribute by implementing CO2 capture and storage technology, which will be responsible for reducing CO2 emissions in the sector by up to 56% by 2050. One way to capture and store CO2 is through carbonic curing of non reinforced cementitious material. In the carbonation reaction, carbon dioxide (CO2) reacts mainly with calcium hydroxide (Ca(OH)2) and hydrated calcium silicates (C–S–H), mineralizing in the form of CaCO3, such as calcite, vaterite and aragonite. The literature shows that the precipitation of CaCO3 in the pores of the cementitious material alters the porosity, increasing the density and promoting the improvement of the physical and mechanical properties of the material, in addition to contributing to the environment by definitively incorporating CO2 in the form of stable minerals. In this research, the aim is to perform carbonic curing in concrete blocks, choosing this cementitious material because it is made from a dry, unreinforced concrete mix, whose geometry of narrow and hollow walls tends to promote greater diffusivity of CO2 inside the piece. Concrete blocks and samples extracted from these respective blocks with 4 MPa and 16 MPa will be used in order to verify the axial compression resistance of the blocks and samples, obtaining the correlation factor between them. A carbonation chamber will also be built to perform the treatment with CO2 for 2 hours, 4 hours, 8 hours and 16 hours. The percentage of CO2 captured will be evaluated through the thermogravimetry and derivative thermogravimetry tests. Working with concrete blocks, the objective is to develop and apply a methodology for the capture, storage and use of carbon in a full-scale industry, also carrying out a technical feasibility study for the implementation of carbonic curing with CO2 in concrete block factories in the greater São Paulo region - SP.