Concrete is a material used in various applications, involving paving, sanitation, infrastructure and superstructure works, dams, bridges, and architectural elements, but for certain applications their physical and mechanical properties are affected by intense degradation agents, motivating the search for artifacts that improve these properties and increase the useful life and durability of matrix materials cement industry. The objective of this work is to clarify the influence of different mix of superplasticizer, steel fibers, water/cement factor, different types of mineral admixtures, besides the type of thermal treatment and method of cylindrical concrete molds of reactive powders, evaluating the resistance to axial compression at the ages of 7 and 14 days. 17 compositions were defined, by mass, for the manufacture of concretes, divided into two stages: the first composed of 10 compositions, and the second by 7 compositions. It was used CP-V ARI cement, sand, metakaolin, silica fume, superplasticizer and kneading water with temperature between 1 and 3°C. After the conformation of the cylindrical molds of dimensions 5x10cm with the aid of a portable immersion vibrator, the specimens were unmolded after 24 hours and received thermal treatment with periods of pre-cure and isotherm that varied according to the defined trait. According to the results obtained, the reduction of the w/c factor and the superplasticizer additive presented higher resistance to compression, however, this reduction in an excessive way impairs the hydration process, implying in the incomplete hydration of all the cement particles, resulting in less resistance. It was observed that the application of thermal treatment and densification by means of layer immersion vibrators acted as essential factors in the increase of the resistances, and that the isotherm time of the composite corroborates the respective increase, until its stabilization, in the temperatures studied.
This work evaluates mortars using sewage sludge calcined at temperatures of 600°C and 700°C as a hydraulic binder replacing the cement. The percentages incorporated by mass to replace the Portland cement were 10%, 20% and 30%, using the 1:3:0,60 (cement: sand: factor a/c) trace. Sludge ash was characterized and tensile strength at flexion as well as tensile strength (pullout test) were evaluated. As a way of performing a comparison with conventional mortars, the same tests were carried out using reference mortar. The results of the flexural tensile strength tests indicated that results were higher than the reference traces of the mortars with the calcined sludge at a temperature of 700°C, a factor related to the increase of the calcination temperature and the incorporated percentage. With respect to the tests on the determination of tensile strength, it was observed that the specimens submitted to the test suffered rupture in the mortar, and that the calcination temperature of the sewage sludge was not influenced. The results obtained with the mortars using sewage sludge ash with partial replacement of the cement are shown within the normative standards and approximate to the results obtained with the tests executed with the reference mortar.
The exponential advancement of cutting-edge technologies in the scope of civil construction, seeks to give cement-based materials the eco-efficient potential linked to mechanical performance that enables different applications. This work aims to evaluate the glass residue regarding the pozzolanic potential through ABNT NBR 5752:2014, as well as to verify whether through the characterization tests of x-ray fluorescence, x-ray diffraction and laser diffraction granulometry, if it is viable of application as supplementary cementitious material (filler), in ultra-high performance concrete. The glass residue submitted to the tests proposed in this study, was crushed in a jaw crusher, milled in a bench ball mill at 47 rpm, and was sieved in a 75 µm opening mesh (ABNT nº 200 mesh). For the test of pozzolanic activity, CP II F-40 class cement, normal sand, water from the public supply network, and superplasticizer additive were used for the mix with 25% of the residue replacing cement, while for the other characterization techniques, the glass residue was applied in its processed form (after sieving), dry or wet. The evaluated glass residue did not reach the minimum rate of 75% established by ABNT NBR 5752:2014, achieving only 45.72%, being classified as non-pozzolanic, which indicates its inert behavior in the presence of calcium hydroxide. The characterization tests confirmed, based on the specialized literature on ultra-high performance concrete, its viability as a filler when adopted as an alternative raw material for presenting chemical and mineralogical composition, in addition to granulometric distribution, very close to those used in studies that demonstrated satisfactory results when using the glass residue as an input.
For many years there has been an accommodation by the construction industry because it is believed to be a craft, rustic activity, being considered cautious and even inappropriate for the insertion of new building systems. Nowadays, the reduction of costs and lead times, as well as the increase of profit margins, are the main goals of construction companies owners, where in the construction industry, in the vast majority of projects, the speed of construction and the use of new technologies are market demands, which makes it more competitive. The challenging globalized scenario encourages the standardization of future development guidelines for all industries in the country, particularly construction. This paper presents the industrialized construction as well as the constructive characteristics of this system and the expectations of its wide use in the construction industry through a study of case in a work placed in Santa Rita, Paraíba. The project is part of the Minha Casa Minha Vida Program of the Federal Government.
Based on the environmental assumptions that permeate the role of researchers in enabling the use of waste in consumer goods, using sewage sludge in human consumption material has become the object of worldwide study because of the potential that it carries. Aiming to fulfill the sustainable role through the creation of mechanisms that favor the ecological coexistence between environment and human beings, the use of the calcined sewage sludge as a potentiator in the properties of the material is made possible through the construction materials, behavior. Coating mortars are currently evaluated by exposing, from the replacement of the cement by the calcined material, an effective applicability with respect to its resistance to deleterious agents. It is understood that to idealize unconventional materials with the use of residues that have high degradation power to the environment, ratifies the attempt to mitigate large and irreversible environmental impacts arising from improper and poorly planned disposal.
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