Key Engineering Materials Vol. 668

Abstract: Worldwide, the purpose of enhancing sustainability, circular economy, use of by-products and renewable resources, has an increasing interest. Adding value to vegetable tropical resources is one of the challenges of COVACHIM-M2E laboratory. In this paper, sugar cane bagasse is evaluated both as mineral replacement and as reinforcement in cementitious matrices. In the modified matrix, cement is partly replaced by natural pozzolan and bagasse ashes, thus a ternary matrix is obtained. Composites materials are then elaborated by incorporation of bagasse fibers in this modified matrix (2 to 6 weight percent).The thermal conductivity and bending strength of the composites placed in a climatic chamber (25°C, 50% of relative humidity) are evaluated and compared to composites made with commercial cement and bagasse fibers, exposed to identical aging conditions.

Abstract: Particleboard industries, which are progressively increasing in number, consume a significant amount of wood from planted forests, mainly from the Pinus and Eucalyptus genera. However, these panels can be produced from any lignocellulosic material that provides high mechanical strength and good physical characteristics. Accordingly, the waste generated by the Brazilian agribusiness industry is an alternative resource for manufacturing particleboards. The study aimed to evaluate the effect of the combination of sugarcane bagasse and eucalyptus wood on the physical and mechanical properties of particleboards. The panels were produced with sugarcane bagasse in the proportion of 0, 25, 50, 75, and 100% supplemented with E. urophylla. The panels were produced with 9% urea-formaldehyde adhesive, nominal density of 0.70 g/cm3, and with the pressing cycle of 160°C temperature, specific pressure of 3.92 MPa, and operation time of 8 min. The significance of the proportion of sugarcane bagasse on all physical and mechanical properties was evaluated. The panels with the combination of wood with sugarcane bagasse showed the lowest values ​​in the physical properties and the highest values ​​in the mechanical properties. Only panels prepared with 25% and 50% sugarcane bagasse met all the requirements of the marketing standards.

Abstract: The intense waste generation moved by the urban and industrial activity and the wasteful consumption of natural resources, encourage the development of new technologies for the utilization of wastes and its reuse in new industrial processes, which decreases the environmental pollution and the removal of virgin materials. In this sense we work in the development of new materials and components from urban and industrial waste prepared by different techniques and with various applications.We work on the development of a composite material made with recycled rubber from tires out of use (NFU) and recycled polyethylene, linked through the fusion of the plastic and the subsequent pressing of the material. In this article we present the partial results obtained in the physical and mechanical testing of the roof tiles, and the burning behavior of the components manufactured with flame retardants additives available in the market, to comply with the regulations in order to use these housing components. These components have as main advantages the high resistance to flexion and the hard impact, low thermal conductivity, and low water absorption by immersion in water. Despite the fact that the components do not meet all the points of the reference Norm in regard to its behavior when exposed to fire, further amendments in the formulation and the manufacture process have shown interesting results, with which roof tiles could comply with the regulation for the use proposed.We developed a sustainable covering system for roof using two types of wastes in great abundance in all urban sites, which involve a simple manufacture process. Besides, due to its high flexibility and resistance to impact hard is presented as a good constructive alternative for housing covering in areas affected by the fall of hail or by the risk of blowing up and deterioration by strong winds.

Abstract: It is well known that the combustion of agricultural waste such as rice husk, bamboo leaf and bagasse among others, depending on the combustion process, may produce powders with pozzolanic properties. Two samples of sugarcane bagasse ash (SCBA) from Honduras were studied (from Ingenio Santa Matilde, close to the city of San Pedro Sula, and from Ingenio Los Mangos, close to the city of Choluteca). The samples were physico-chemically characterized and pozzolanic reactivity was checked. Both samples of ash have a chemical composition comprising mainly oxides of silicon, iron and aluminum and have similar values of the loss on ignition. Both ashes showed high ability for reacting towards hydrated lime. Moreover, the evolution of the mechanical compressive strength of mortar specimens incorporating these ashes (25% replacement of Portland cement by SCBA) was also studied. Compressive behavior revealed that for this dosage, the cementing efficiency of SCBA is similar to Portland cement.The results suggested that ashes from San Pedro Sula and Choluteca have very good pozzolanic properties. The cement and concrete industries in Honduras have a huge chance for reusing this type of waste in high quality construction materials. Keywords: pozzolan, sugarcane bagasse ash, agricultural waste, mechanical strength.

Abstract: Since the construction industry is responsible for 30% of the CO2 emissions, one way to reduce the impact of the construction activity is to substitute ordinary Portland cement by pozzolanic materials. The application of using agricultural waste in the production of pozzolanic material is technically feasible, due to the calcination of organic materials and leaving ashes with a fine particle size and high SiO2 content. In the present, it is discussed the pozzolanic effect of sugarcane bagasse ash (SCBA) from Taretan, Michoacán, Mexico, on the physical and mechanical properties of a portland cement mortar. Test specimens were prepared based on replacing sugarcane bagasse ash percentages of 5, 10, 15, 20 and 30 %, relative to the weight of cement. To validate the mechanical properties of the specimens, tensile, flexural and compressive strength was determine. The porosity of the mortar was determined by means of non-destructive ultrasonic testing of pulse rate and electrical resistivity. The contribution of this paper was determine the bond strength of an overlay mortar with SCBA bonded to the concrete substrate by pull-out tests. The results showed that the addition of the sugarcane bagasse ash improved the mechanical strength, adherence of the mortar to concrete, and decreases the porosity on large curing times. Hence, it is suggested the use of Portland pozzolan cement containing sugarcane bagasse ash pozzolan, with the added benefit on the use of agricultural waste.

Abstract: In parallel with the growing demand for lumber, there has been an increase in the amount of waste generated by this industry, such as chips, shavings, and sawdust as the main waste. Such wastes are disposed in unsuitable locations or burned for energy generation. The present study aimed to evaluate the use of sawdust for particleboard manufacturing. The particleboard were produced with Pinus oocarpa wood and 11% urea-formaldehyde adhesive, with a nominal density of 0.70 g/cm3 and a pressing cycle of 160°C temperature, specific pressure of 3.92 MPa, and a operation time of 8 min. The panels were evaluated for the properties such as apparent density, thickness swelling after 24-h immersion in water, Janka hardness, screw pullout (top and face), compression ratio, internal bond, according ASTM D1037 (2006) standard and modulus of elasticity (MOE), and modulus of rupture (MOR) to static bending acordingo DIN 52362 (1982) standard. The panels produced with sawdust of P. oocarpa wood met all the requirements stipulated by the marketing standard, demonstrating great potential for use in particleboard manufacturing.

Abstract: Particulate composites can be manufactured using low-quality raw materials, thus presents the option of using various non-wood materials, including agricultural waste. This study aimed to evaluate the effect of using castor hull and sugarcane bagasse on the physico-mechanical properties of particulate composites. Particleboards were produced using raw materials such as Pinus oocarpa wood, castor hull (Ricinus communis), and sugarcane bagasse (Saccharum officinarum) in different proportions: 1) 100% P. oocarpa wood; 2) 100% castor hull; 3) 100% sugarcane bagasse; 4) 50% P. oocarpa wood and 50% castor hull; and 5) 50% P. oocarpa wood and 50% sugarcane bagasse. The produced panels had a nominal density of 0.70 g/cm3, 8% urea-formaldehyde adhesive, specific pressure of 3.92 MPa, temperature of 160°C, and pressing time of 8 min. The panels produced with sugarcane bagasse, with or without pine wood, showed better dimensional stability. The panels produced with sugarcane bagasse only or with castor hull only showed the lowest values ​​of modulus of rupture and elasticity to the bending. However, despite these differences among the treatments, all treatments met the requirements of the EN 312 (2003) standard for internal use panels.

Abstract: Kraft pulping is currently the most widely used technique in the production of cellulose pulp, and the production process generates large amount of lignocellulosic residues. Looking to add value to this residue, the aim of this study was to evaluate the physical and mechanical properties of extruded cementitious matrices reinforced with lignocellulosic waste from the kraft pulping of Eucalyptus spp wood. The experimental design were consisted of 3 treatments with 5 samples for each treatment, as follows: 1) 70% Portland cement (by mass) with 30% ground carbonate (by mass) - T1; 2) 66.5% of Portland cement, 28.5% ground carbonate and 5% residual pulp fibers - T2, and 3) 69.5% Portland cement, 25.5% metakaolin and 5% residual pulp fibers - T3. The mass for extrusion was prepared with the addition of hydroxypropyl-methylcellulose (HPMC) and polyether carboxylic (ADVA) as rheology modifiers, with water:cement ratio of around 0.3. After mixing, the mass was taken to an extruder where the specimens were obtained. Apparent porosity (AP), bulk density (BD), water absorption (WA), modulus of rupture (MOR), fracture toughness (K_IC) and fracture energy (EF) were evaluated. There was statistical difference between the treatments for AP, BD, WA, K_IC and EF values, and the treatment with the metakaolin showed the lowest values for BD and the highest values for AP, WA and FE. The treatment with ground carbonate and residual pulping showed intermediate results when compared to the other treatments. No statistical differences were found between the fiber-cement treatments for MOR values.

Abstract: The southwest region of Goiás is a major grain producer in the country, with emphasis on soybeans. It is protected by a pellicle grain into a legume. After its separation, the film is eventually discarded or used as animal feed. One alternative is the production of particleboards, considering lignocellulosic material, which could add value to this raw material. In this sense, the objective of this study was to evaluate the dimensional stability of particleboards produced with soybean residue, comparing them with eucalyptus panels. The particleboard was made with a nominal density of 0.55 g/cm³, and 12% of urea-formaldehyde adhesive were used, based on their content of resin solids and pressing cycle of 3.92 MPa, 180oC for 15 minutes. Three panels were produced by treating. The assessment of dimensional stability was made by measuring their density, water absorption and thickness swelling after immersion for 2 and 24 hours. Based on the results, it can be seen that, statistically, the panels had equal densities, an average value of 0.52 g/cm³. It is noted that the panels produced with a soy film had water absorption values of 2 to 24 hours, and thickness swelling in 24 hours, in comparison with the upper eucalyptus. For thickness swelling after 2 hours, no statistically significant difference between the tested materials was observed.

Abstract: Currently a lot of bottles of polyethylene terephthalate (PET) are discarded into the environment. In order to reduce the disposal of this polymer in nature, this study aims to evaluate the mechanical behavior of a clayey soil mixed with fine crushed PET. The potential use of this waste material in geotechnical applications may ultimately reduce the problem of improper disposal and improve the strength and deformation characteristics of the soil. This paper presents an experimental study to evaluate the mechanical behavior of pure soil and mixtures with different contents of PET waste by triaxial tests, in order to obtain the strength parameters of the Soil-PET mixtures. The clayey soil used was mixed with 10 and 20 percent of fine crushed PET by dry weight. Characterization tests such as grain size, Atterberg limits and compaction test were performed on the soil-PET mixtures. Triaxial tests at confining stresses of 50, 150 and 300 kPa were done on the soil and mixtures. The results show that the soil strength parameters are influenced by the addition of the fine crushed PET, thus improving characteristics such as friction angle and cohesion of the Soil-PET mixtures. This improvement also depends on the confining level which the samples were submitted. These mixtures may be used in pavement and other geotechnical works, so this paper proposes to contribute to a better understanding and interpretation of the behavior of reinforced soil with waste PET.