Marcos M. Silvoso

Cement replacement by sugar cane bagasse ash: CO2 emissions reduction and potential for carbon credits.

This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO(2) emissions into the atmosphere. SCBA is a by-product of the sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the worlds largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO(2) emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO(2) emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO(2) emissions, which qualifies this product for CDM projects.

Determining the adiabatic temperature rise of concrete by inverse analysis: case study of a spillway gate pier

This paper presents a method to find the adiabatic temperature rise of concrete by retro-analysing temperatures measured in the field. The construction phase is simulated with a 3D finite-element model that considers the coupling between thermal and chemical phenomena due to cement hydration. A genetic algorithm is used to find the main parameters that characterise the adiabatic temperature curve and that better fit the temperatures measured in the field for a given structure. This method was applied to the construction of the spillway gate pier of a hydroelectric power plant. The good agreement between numerical results and temperature measurements points to the feasibility of the proposed method.

Study of the Technical Capability of Sugarcane Bagasse Ash in Concrete Production

Cement industry has a great contribution to CO2 emissions in the world. In order to reduce the levels of CO2 emissions and the consequences of global warming, some researches have been developed aiming to reduce the cement volume produced through mineral mixtures. Sugarcane bagasse ash (SCBA) represents an important environmental liability of the alcohol industry in the northern state of Rio de Janeiro and its use as a partial replacement of Portland cement in concrete has shown great potential for use. This paper aims to analyze, through experimental procedures, the consistency and mechanic strength on concrete with low environmental impact, made from sugarcane bagasse ash, in substitution levels of 20% and 40%. The methodology of the experimental program, included the steps of characterizing the materials; definition of the reference concrete; molding and dosing of the reference concrete and concrete with SCBA; mechanical tests to evaluate the resistance in the reference test bodies; and analysis of the results. The method used from production and processing of the ash to the characterization of other materials in the concrete are also addressed in this study. The results indicate the feasibility of using sugarcane bagasse ashes in application of concretes in the construction industry.