Papers by Keyword: Alternative Materials

Abstract: The problem of corrosion in reinforced concrete infrastructure can be addressed by using fibre-reinforced polymer (FRP) bars, since they are a feasible alternative due to their non-corrosive nature. Basalt fibre-reinforced polymer (BFRP) bars have recently gained attention as a possible substitute for both of these materials because they are less expensive than Carbon Fibre-Reinforced Polymer (CFRP) and have greater tensile strength than Glass Fibre-Reinforced Polymer (GFRP). While considerable research has been conducted on CFRP bars and GFRP bars, studies on BFRP are limited, hindering its incorporation into design guidelines. Therefore, in this study, bond behaviour of BFRP bars in concrete is experimentally evaluated. This study concludes that although BFRP bar shows more slip than steel bar, its bond strength is comparable to that of steel bar. It is also found that the bond strength and maximum slippage reduced with an increase in the bars' diameter and embedment length. Furthermore, the bond strength improves as the cover increases. Furthermore, bond strength equations as proposed by ACI 440.1 R15, CSA S806-02, and CSA S6-06 underestimated the experimental bond strength.

Abstract: The use of waste materials as a substitute for natural aggregate has been widely tested in all areas of the construction industry. Yet, there is a lack of study on the suitability of the physical properties of waste material when used as one of the components in track ballast. This study evaluates the suitability of conventional ballast (CB) incorporated with concrete debris (CD) and bottom ash (BA) as track ballast material. To achieve the objective, sieve analysis, shape analysis, specific gravity test, water absorption test, and permeability test were carried out. Furthermore, microscopic analysis was used to validate the presence of voids. The result shows that the waste mixed ballast has a coefficient of uniformity (Cu) in the range of 1.92 to 12, a coefficient of curvature (Cc) in the range of 0.8 to 1.18, fines less than 14 mm account for 0.1 % to 28 %, and the mean size is in the range of 22.5 mm to 27.5 mm. Furthermore, the flakiness ranged from 7.56% to 22.5%, the void ratio was 0.43 to 0.55, and water absorption was 2.86% to 4%. The specific gravity was found to range from 2.30 to 2.77 when the permeability measurement was in between 30 cm/sec to 61 cm/sec. All these promising values of engineering properties exhibit the confidence of a suitable alternative to track ballast materials. Hence, CD and BA waste materials incorporated into conventional ballast have a high potential to exhibit better performance and reduce the dependency on natural aggregate.

Abstract: The response of the bulkhead type of blast wall under deflagration blast pulse was studied using finite element modelling software. The behavior of unstiffened and stiffened panels was analyzed. The study aimed at determining the effect of plate and stiffener thicknesses on energy dissipation and distribution of reaction forces. This was carried out in order to optimize the response of the primary steelwork through typological and geometrical modifications of the local element. Furthermore, novel strategies for the improvement of the blast response were introduced with a focus to use alternative materials and innovative connections. The latter was assessed numerically using a simplified model and its benefits were analyzed by comparing with the traditional approach.

Abstract: We study the sound absorption coefficient of rubberized mortars in response to the incorporation of 7.5%, 15% and 30% of waste-tire rubbers in place of sand at a water-to-cement mass (w/c) ratio of 0.48. We consider two different morphologies of rubber particles, namely spheroid (S) and fiber-like (F) particles. Experimental characterization was performed after 7 days of curing. The mixtures were performed by density, water absorption, void index and sound absorption. We choose the transfer function method with one microphone successively in two locations in order to obtain the sound absorption coefficient using an impedance tube. Sound absorption coefficient results indicate a slightly enhancement for 7.5% S, 15% S, 30% S and 7.5% F mixtures from 1600 Hz to 2000 Hz. The best acoustic performance is observed for 30% S and 7.5% F mixtures from 850 Hz to 2000 Hz.

Abstract: The use of alternative materials as substitutes for ordinary aggregates, mainly in concrete and mortar, has been common in recent decades in Brazil. Due to its physical and chemical similarities to common aggregates, ceramic waste, when coupled with a granulometric control, is suitable for use as an aggregate in concrete. Brazil has been estimated to dispose of approximately 25,000 tons of porcelain insulators annually, which are insulators that are often discarded along with other debris and harm the environment. This study examined the grinding methodology for and subsequent use of porcelain to replace fine aggregates in concrete and verified the improvement this substitution provided by evaluating the mechanical properties and durability of the concrete under study and examining scanning electron microscope images.

Abstract: This study aims to address the question of accessibility on sidewalks in accordance with Rule 9050 of the Brazilian Association of Technical Standards (ABNT NBR 9050:2004) and analyze the feasibility of using alternative materials (steel fibers, construction waste and rubber) to produce Interlocking tactile concrete paver. It was performed an experimental dosage of concrete with 04 specimens: reference, with steel fiber, with rubber and with steel fiber and construction waste. The pavers molded with conventional concrete and with the addition of alternative materials were tested as for compression strength and water absorption and the results were satisfactory, meeting the specifications of the Brazilian standard.

Abstract: 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.