ABSTRACT Carbonation chambers, in general, are used in civil engineering laboratories both for verification tests of the useful life of reinforced concrete, and for CO2 curing tests of unreinforced cementitious materials. These chambers can be purchased from specialized manufacturers at a high cost, or they can be built by the researchers themselves. It so happens that in the literature there is no manual for making and operating an accelerated carbonation chamber. It is observed that its development and manufacture depend a lot on the needs and financial conditions of the research, with no standard or Technical Norm to be followed. This article presents a compilation of concepts related to the accelerated carbonation reaction and brings a bibliographical review about the different carbonation chambers made by researchers, in which it was possible to verify a great variation regarding the material to be used in the structure of the chamber, location of CO2 and air inlet and outlet valves, temperature and humidity control, among others; and in addition, it presents a descriptive memorial for the construction of an automated and accessible carbonation chamber to be used in laboratories. general concrete CO materials cost themselves research followed valves control others addition

resumo: A análise de viabilidade de projetos determina se o projeto deve ou não ser colocado em prática e pode ser realizada a partir de diferentes esferas: estratégica, técnica, operacional, legal, econômico-financeira, ambiental, mercadológica, política, fiscal, localização, entre outras. As referidas análises não são excludentes, por conseguinte, é possível que para um único projeto sejam realizadas todas elas. No entanto, este trabalho terá enfoque na análise da viabilidade técnica do projeto inovador de implementação da cura química com CO2 em fábrica de blocos de concreto na região de São Paulo. Para tanto, será apresentada uma visão geral do processo de cura com CO2 e possíveis modificações para realizá-la na indústria, além da identificação de fontes locais de CO2 e custo de entrega, necessidades de mudanças na câmara de cura, aquisição de novos equipamentos, possíveis melhores definições sobre temperatura ideal, umidade e concentração de CO2. Casos de sucesso internacionais são apresentados. O estudo conclui que a tecnologia pode ser facilmente implantada na região, com poucas mudanças no processo produtivo da planta e na câmara de cura. Dependendo da distância da fábrica ao fornecedor de CO2, poderá haver um aumento de 4% a 14% no custo do bloco. Considerando a produção brasileira de blocos de concreto, até 168.780 toneladas de CO2 por ano podem ser sequestradas, este valor equivale ao sequestro de CO2 realizado por 21.100 árvores.

abstract: The project feasibility analysis determines whether the project should be carried out from different spheres: strategic, technical, operational, legal, economic-financial, environmental, marketing, political, fiscal, location, among others. These are not excluding analyzes, all aspects must be assessed before implementing a new project or new process. This work will focus on the analysis of the technical feasibility of the innovative project to implement carbonation curing in a concrete block factory in the region of São Paulo. An overview of the CO2 curing process and changing needs is presented, including identifying local CO2 sources and delivering cost, gas consumption for chamber saturation, estimation of CO2 uptake by masonry units during curing, estimation of consumption and monthly cost of CO2, curing chamber changes needs, new equipment acquisition, estimation of cost for retrofit and new installations, potential best definitions on optimal temperature, humidity, and CO2 concentration. International succeeded cases are presented. The study concludes that the technology can be easily implemented in the region, with few changes on a plant production process and on the curing chamber. There would be an increase of 4% to 14% on the block cost depending on the distance to the CO2 supplier. Considering the Brazilian production of concrete blocks, up to 168,780 tons of CO2 per year can be sequestered, this value is equivalent to the CO2 sequestered by 21,100 trees.

This work presents a study, which compares the early stages of hydration of a High Initial Strength and Sulphate Resistant Portland Cement (HIS SR PC) with those of Type II F Portland Cement (PC II), by Non-Conventional Differential Thermal Analysis (NCDTA) within the first 24 hours of hydration. Water/cement (w/c) ratios equal to 0.5, 0.6 and 0.66 were used to prepare the pastes. The hydration of these two types of cement was monitored on real time by NCDTA curves, through the thermal effects of the hydration reactions, from which cumulative evolved energy curves were obtained. These techniques allow one to analyse the influence of each type of cement on the main stages that occur during the hydration process. Thermogravimetric analysis were also performed at 4 and 24h of hydration for both cements, to analyse the influence of each kind of cement on the amount of the main formed hydrated products. The results showed that with 4h of hydration, the total combined water amount released from the hydrated products was higher for the PC II pastes than for the HIS SR PC pastes. Otherwise, with 24h of hydration, the amount of the total combined water released from the hydrated products was higher for the HIS SR PC pastes than for the PC II pastes.