Study of common Portland cement/Brazilian bentonite systems

Reference	Presenter	Authors (Institution)	Abstract
04-101	Rennan Willian Maria	Valenzuela Diaz, F.M.(Universidade de São Paulo); Maria, R.W.(Centro Universitário Estácio de São Paulo); Neves, F.D.(Centro Universitário Estácio de São Paulo); Brasil, M.D.(Instituto Federal da Bahia); Oliveira, O.M.(Instituto Federal de Educação, Ciência e Tecnologia da Bahia, campus Vitória da Conquista.); Esper, F.J.(USP); Silva Valenzuela, M.d.(Escola Politecnica da Universidade de Sao Paulo); Valenzuela-Diaz, F.R.(Polytechnic School of the University of São Paulo);	Water / cement / bentonite systems are important in the oil extraction in the cementation of the wells and in the preservation of the environment as cut-off walls. The properties of such systems using Brazilian bentonites have not been sufficiently studied. In this work, water / Brazilian bentonite / common cement systems were studied. The Brazilian polycationic bentonite, from the State of Paraíba, and the common Portland cement used were characterized by chemical analysis, granulometric analysis, XRD, SEM and thermal analysis. Because it is of the type of bentonite that does not swell in water the bentonite was previously submitted to processes of cationic exchange by sodium using sodium carbonate. The water swell of the modified bentonite was evaluated by means of Foster swelling tests. The rations, by weight, of water / cement used ranged from 0.5 to 1.2. The bentonite / cement rations used, in weight, ranged from 1 to 20. The bentonite was initially added to the water and then the cement was added. The viscosities of the slurries obtained were measured by Ford or Fann viscometers. Cylindrical test specimens were formed, which after seven days on humidity chamber had measured their density, porosity, and resistance to compression. Test specimens with the best strength / density ratios were submitted to XRD tests and their mechanical strength, density and porosity was measured after staying in umidity chamber for 1 day, 3 days and 5 days.
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