Andressa Fernanda Angelin

Effects of Consumption of Cement in Mechanical Properties of Lightweight Concrete Containing Brazilian Expanded Clay

Concrete is one of the oldest building materials known to humankind. From 1824, with the advent of Portland cement, concrete assumed a prominent place among the construction materials, due to large amounts of strength, durability and versatility it offered compared to other products, allowing the molding of various forms architectural. Until the early 80s, the concrete remained only as a mixture of cement, aggregates and water, however, in recent decades, due to the development of new techniques and products, the concrete has been undergoing constant changes. The concrete with lightweight aggregates have been used since the beginning of the last century, with low values of density (< 2000 kg/m3), demonstrating the great potential of using this material in several areas of construction [. With the objective of analyzing the influence of the consumption of cement in conventional concrete and light, were molded, tested and compared body-of-evidence containing two different amounts of cement consumption: a) 350 kg/m3 and b) 450 kg / m3. The results were compared with those obtained by other researchers, as well as with [ and [.

Mechanical Evaluation of Concrete Containing Lightweight Aggregates

Since the invention of modern concrete, in the mid-nineteenth century until the early 80s, the concrete remained a mixture of aggregate, cement and water, with no major innovations that significantly alter the performance of its properties. But in recent decades, concrete technology has undergone tremendous development that has occurred due to the development of techniques and equipment for the study of the concrete and the use of new materials.The concrete with lightweight aggregate have been used, mainly due to the low values of density, thus demonstrating the great potential of using this material in several areas of construction [.With the objective of analyzing the influence of the consumption of cement in conventional concrete and light, were molded, tested and compared body-of-evidence containing two different values of cement consumption. The values were compared with those obtained by other researchers, as well as with the ABNT NBR 6118:2003 [ and ACI 213R-03:2003 [.

Use of expanded clay and silica fume for the improvement of mechanical, physical and thermal performances of structural lightweight concretes

In this study an investigation was carried out for the execution of concretes with high strength, low density and excellent thermal properties, in order to execute energy-efficient constructions. Structural Lightweight Concretes were studied using two different granulometries of expanded clay (C05 and C15), where the coarse aggregate was replaced by 0, 25, 50, 75 and 100%. To promote the maintenance of consistency and resistance, superplasticizer and silica fume were used in the mixtures. Based on the methodology used, the concretes were physically and mechanically characterized, in accordance with current national and international standards. The density of the concretes, in the hardened state, ranged from 1,787 to 2,400 kg/m3 and, for compressive strength, ranged from 26 to 53 MPa at 7 days of age. The thermal conductivity test, using the protected hot plate method, was performed according to EN 12667, where was observed a variation of 0.61 to 1.00 W/mK. Microstructural information of the interfacial transition zone between aggregate and cement matrix were obtained with the purpose of analyzing the relationship with mechanical resistance. The investigation revealed that, with the addition of expanded clay (C05 and C15) and silica fume in the concretes, there was reduction of the density and the mechanical resistance, while the thermal characteristics improved.

Study of Density and Modulus of Elasticity of Lightweight Concrete with Brazilian Aggregate

Concrete is one of the oldest building materials and applying known to humankind. From 1800s, with the advent of Portland cement concrete has taken a prominent place among the construction materials due to large values of strength, durability and versatility it offered compared to other products, allowing the molding of the various architectural forms. Until the early 80s, the modern concrete remained only as a mixture of cement, aggregates and water, however, in recent decades, due to the development of new techniques and products, the concrete has been undergoing constant changes [. This article discusses the application of technology of lightweight aggregates for concrete production, for use in building elements such as structural panels or fence. Developed an experimental program for the analysis of concrete, with the primary objective to characterize the properties of the parts in the hardened state. The results showed that the lightweight aggregate concrete with Brazilian expanded clay are extremely suitable for the production of prefabricated elements slender, mainly due to the reduction in density and excellent performance in mechanical properties, especially modulus of elasticity, despite the low toughness of lightweight aggregate.

Studies of Mechanical Properties and Absorption of Lightweight Concrete with Brazilian Expanded Clay

Brazilian Expanded Clay. The production process in a rotary kiln (or nodule) used in Brazil, characterized by the fact that certain materials expand when subjected to high temperatures (between 1000 °C and 1350 °C), such as some clays. In this temperature range, some of the material melts generating a viscous mass, while the other part chemically decomposes releasing gases which are incorporated by this mass, expanding by up to seven times its initial volume, the pore structure being maintained after its cooling. This manufacturing process promotes the formation of a glazed layer on the outside with low particle porosity, which significantly reduces the water absorption, has varying particle size and regular rounded shape, and its specific gravity comprised within the range from 0.64 to 1.51 kg/dm3 [4, .