Co-generation biomass wastes in low Co2 cement composites and concretes: Combining energy efficiency and technical performance in sustainable building materials

Biomass-based energy represents an increasing relevance in the Brazilian energy matrix, representing 24 % of the Brazilian overall energy production in 2012. Besides the amount of the energy obtained, its qualitative aspect is as much as important, as it is accounted in the renewable energy share. Considering the Brazilian agricultural activity, the energy production from biomass can be still significantly increased and energy cogeneration from biomass burning is one of the process that contributes to support this grow. As an example, almost all of the more than 500 sugar cane mills in Brazil burn the sugar cane bagasse to generate electrical energy. The main waste from the energy cogeneration is the biomass ash, a mix of mineral compounds and remained carbon-based components. Portland cements and concretes are the most widely used manufactured materials in the world, consuming large quantities of raw materials and energy and being responsible for a significant share of the CO2 emissions. One of the main strategies to reduce the environmental impacts from cement production is to combine the cement clinker to supplementary cement materials (SCM), resulting in blended cements. This paper focus on the potential of biomass ashes resulted from the energy cogeneration as SCM in cement-based materials. There are presented results from research in which sugarcane bagasse ash (SCBA) are used as SCM, resulted in cement composites and concretes with improved properties.