Navegando por Assunto "argamassa"
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Item Estudo da propriedade resistência superficial em revestimentos de argamassa(Universidade Federal de Goiás, 2009-09-20) ALVES, Amália Silva; CASCUDO, Oswaldo; http://lattes.cnpq.br/3336749062812376; CARASEK, Helena; http://lattes.cnpq.br/3023241186996790The lack of cohesion in mortar renderings corresponds to the loss of mechanical strength among theirs layers due to the weakening of particles bond, a fact which is reflected, among other events, by a low surface resistance of these renderings. Thus, poor surface strength of mortar renderings accelerates their degradation process, leading to a significant reduction in the level of their performance and leading to failures in the functions assigned to them. In this context, this basically experimental research aimed to study the property of surface strength in mortar renderings. So, was investigated the applicability of some test techniques, pendulum hammer, dynamometer traction and ultrasounds (by indirect method) to evaluate surface characteristics of the mortar renderings. In addition, were also evaluated the effects of moisture absorbed by the renderings, the influences of composition, air entrained content and application way in the surface strength of the mortar renderings. In this study, the experimental program was divided into two stages. In the first stage, were used: one mortar mixed (cement: lime: sand) and one industrial mortar (with air entrained content equal 20%) applied in one type of substrate (concrete surface - standard substrate ABCP) by compressed air projection, so that their produced coverings were tested under different conditions of moisture (oven-dry, dry environment, wet and saturated). In the second stage, were used: one mortar mixed (cement: lime: sand) and three industrial mortars (with air entrained content equal 20%, 30% and 40%) applied to the substrate standard in three ways (manually, by means fall box and by compressed air projection). Using statistical criteria, the main results have shown a significant effect of the four mentioned factors on the surface strength, in view of the testing techniques used. However, only showed no significant the effect of moisture in the hardness index.Item Propriedades físicas e mecânicas de argamassa reforçada com fibras do bagaço de cana-de-açúcar (FBC)(Universidade Federal de Goiás, 2010-02-08) SILVA, Janaina Fernandes e; FERREIRA, Regis de Castro; http://lattes.cnpq.br/3206688887219284In this work survey results are reported, it aimed at assessing, through laboratory tests, the exploitation of bagasse-cane (FBC) in composite cementitious (cement mortar, sand and FBC) assessing the physical and mechanical behavior of the material. Problems of chemical incompatibility between the bagasse fibers and cement matrix components have been removed by specific treatments on the CBF, such as washing, boiling, mineralization with chemicals an a mix of cement and water in different combinations. The sugar cane fibers brake down process, used in other studies conducted with the same material, was not necessary, because nowadays the CBF is already broke down in the production process in the ethanol and sugar industry. The fibers were washed and mineralized with inorganic salts (solution of sodium silicate at 5%; aluminum sulfate solution at 3%) and cream of cement (the concentration of 10:1 of water and cement), in order to protect the fiber against the aggressions of the alkaline mortar, trapping organic matter and the residual sugar to avoid interference in the reactions of cement cohesion, reduce the capacity of water absorption. Different concrete mixtures were tested, in order to find one with better compressive strength. The change occurred in the content of CBF added, may be 1.5 or 3.0% by weight of cement and the type of treatment that these fibers were submitted. Were defined traits and body-of-proof molded and compressed manually into cylindrical molds of 5 cm ø and 10 cm in height, corresponding to five combinations of treatments, two ages, two levels of fiber and three replicates, and two types of reference to variations in curing type (moist chamber and the tank with water and lime). Later, the bodiesof- evidence were submitted to tests of compressive traction in diametral compression and water absorption at 7 and 28 days. The best treatments results were: washed CBF + boiled; washed CBF +boiled+cream cement; and washed CBF + boiled + chemicals.