Papers by Keyword: Water Absorption

Abstract: This research focuses on reusing waste materials to reduce the demand for fresh raw materials, thereby preserving natural resources. This approach also minimizes the energy and greenhouse gas emissions of extracting and manufacturing raw materials. We are developing eco-friendly, versatile polymer composites, aligning with the circular economy movement's goals of promoting sustainable resource utilization and waste minimization through closed-loop product life cycles. This research uses a hybrid polymer reinforced with lignocellulose agro-fibers (LCAF) from vegetable waste residues. Three different agro-wastes, such as orange peels, jute, and palmyra fruit peduncle, have been used. It investigates two phases, initially different fiber ratios from 3 to 12% and varying fiber lengths from 5 to 20 mm in the secondary phase, respectively. The LCAF is obtained through mechanical and chemical pre-treatment to enhance its properties for use in food packaging. The fiber containing 9% LCAF demonstrated a superior hardness and tensile strength of 118 BHN and 63 MPa compared to the polyester matrix. The water absorption improved from 2.03% to 4.76%, depending on the type of raw material and pre-treatment used to produce the LCAFs.

Abstract: This study investigates the water absorption characteristics of epoxy-based hybrid composites reinforced with natural sisal fibers and synthetic glass fibers. Four different stacking sequences of fiber layers: SSSS (four sisal layers), SSSG (three sisal layers and one glass layer), SSGG (two sisal layers and two glass layers), and SGGG (one sisal layer and three glass layers), were fabricated to assess their influence on moisture absorption properties. The water absorption percentages determined during testing of the compositions are averaged, showing a trend of decreased water absorption with an increase in the number of glass fiber layers. The SGGG configuration exhibits the lowest water absorption at 3.18%, while the SSSS configuration has the highest at 6.63%. This trend highlights the absorbent nature of sisal fibers and confirms the role of glass fibers in enhancing water resistance. Hybrid fiber reinforcements can therefore improve not only the mechanical properties of epoxy composites but also make them more environmentally friendly. Such materials provide a viable alternative to conventional plastics. Additionally, understanding the effect of stacking sequences on moisture absorption may enable future composite designs tailored for specific environmental conditions.

Abstract: Natural fibers are widely used as reinforcement in composites and undergo development in the surrounding environment. However, natural fibers have a water-absorbing property that reduces the strength of the composite. The objective of this research was to analyze the percentage increase in water absorption of resin epoxy composite reinforced with woven ramie fibers. In this research, bisphenol a-epichlorohydrin resin epoxy and polyaminoamide hardener epoxy were utilized as the matrix with a volume fraction of 60:40. Various additions of cerepol pigment pastes (CPP) were made to the resin, specifically 5%, 7.5%, and 10%. The composite was fabricated using the hand layup method, molded in a mold with dimensions of 250mm x 250mm x 4mm, and immersed in seawater for 12 days. The results of the study indicated that the woven ramie fibers reinforced composites, both without CPP and with 5% CPP, and 10% CPP, experienced the highest percentages of water absorption, which were 1.34%, 1.28%, and 1.10%, respectively, while the lowest percentages of water absorption were 0.7%, 0.6%, and 0.75%.

Abstract: Bio-based building materials are now being widely explored by researchers to promote their effective use and reduce the environmental impact of building construction. Among these, mortars based on olive kernel aggregate, a waste product of the production of olive oil, can be effectively adopted for moderate load-bearing applications in buildings thanks to their lower density and thermal conductivity,compared to traditional sand-based mortars. Nevertheless, to date most of the researchers focused on mortars produced with a partial substitution of traditional sand with olive kernels and relatively high dosages of binder. In this work, mortars entirely based on olive kernel aggregate were produced employing limited dosages of binder. Mechanical, hygric properties and the density were evaluated on the hardened materials for different tested formulations. Results showed a high dependency of mechanical properties on the dosage of binder and demonstrated their employability for moderate load-bearing applications in buildings.

Abstract: Thermal property of carbon fiber-reinforced polymer composites (CRFPs) fabricated through vacuum assisted resin transfer molding method (VARTM) is investigated using Thermo Gravimetric Analysis/Differential Scanning Calorimetry tool. These analysis on laminate composites with three different orientations are carried out at room temperature up to 800°C. Also, mechanical and water absorption behavior of polymeric composites are determined. Among the orientation effect, a longitudinal direction sample including 39 vol. % carbon fiber in epoxy resin indicated that the mass loss in percentage was lower while decomposition temperature was higher than those of others due to higher mechanical strength. These composites revealed the most thermally stable among the others. Further, lower amounts of water absorption rates were obtained at 0^o-orientation, followed by 0/90^o-orientation composites, but no significant variations occurred with these orientations while some variations occurred for 30^o-orientation with increasing the soaking times.

Abstract: Adobe homes are prone to natural phenomena such as floods, landslides, and earthquakes, due to the intense rains that occur from the month of November to March. This study aimed to investigate the mechanical properties of adobes reinforced with rice husk, lime and neem fibers and evaluate their compressive strength and water absorption capacity. The tests were carried out on adobes with dimensions of 10×10×10 cm3 made with earth, 0.75% rice husk, 0.75% lime and 1 to 3% neem fibers of the total weight of the adobe to determine the evaluations of the specimen. Therefore, a visit was made to the study area located in the province of Yauyos - Peru to classify the type of soil that would be used in the samples, then sift the soil to prepare the mud and let it rest for 24 hours. Then, incorporate the reinforcements and mold the adobes to let them dry for 28 days and proceed with the tests. The research recorded an improvement of 39 and 68% respectively on the strength of adobes reinforced only with rice husk and lime; and neem fibers after 28 days of drying with a proportion of 0.75% rice husk, 0.75% lime and 3% neem fibers. The absorption coefficient of adobes reinforced with rice husk, lime and neem fibers are between 16 and 27% better than adobes reinforced separately. Finally, this research will reduce the damage to homes caused by rains through the use of materials found in the localities and reduce pollution, thus creating a sustainable home with low costs for the inhabitants.

Abstract: This study focuses on eliminating cracks partially in structures by adopting bacteria-based fibre and steel reinforced self-healing concrete. Two bacteria of the genus Bacillus were used, one was cultured from soil, while the other was cultured from parkia. These were subcultured using an algae medium to produce 13500 ml of washed bacteria cells, which were immobilized in 1,500 ml of silica gel. A nutrient solution was also prepared by mixing 171 g of yeast extract, 1710 g of urea, and 1710 g of calcium lactate in water. Water, polyvinyl alcohol (PVA), bacteria cells, and silica gel contributed to the total water content at a ratio of 0.22, 0.03, 0.225, and 0.225 respectively. 81 concrete cubes of and 72 reinforced beams of were cast using 1:2:4 mix ratio. Cracks were created on the surface of the cubes after casting with a 0.6 mm steel plate and were cured for 7, 14, and 28 days. After curing the reinforced beam for 14 days, cracks were created on 36 beams (healed specimen) out of which 18 numbers were cured for 7 days and the remaining were cured for 14 days. 18 beams out of the remaining 36 beams (sound specimen) were tested at 7 days while the remaining 18 were tested at 14 days. The compressive strength, water absorption, and sorptivity results showed that Bacillus spp. (from soil) performed better than the control and Bacillus spp. (from parkia).

Abstract: Pollution problems caused by industrial production of leather tanneries are an important environmental issue. In the present paper we propose to study effects of tannery sludge (TS) addition in manufactured clay bricks applying a mixture design formed by different proportions of four components: Clay, two types of sand and TS. The analysis leads to an optimal practical mixture of around 10% of TS, 20% of sand and 70% of clay and this to remain with an acceptable aspect, an admissible water absorption below 15%, an admissible total shrinkage (drying and after fire) lower than 8%, a tensile strength higher than 5MPa and a thermal conductivity of 0.93 Wm^-1K^-1, 15% lower than the reference mixture with 0% of TS. Experimental results indicate that a temperature cycle firing up to 950°C can lead to higher tensile strength and lower water absorption compared to a cycle that reaches only 850°C. Furthermore, incorporating (TS) in the fired brick manufacturing process can lead to significant energy saving. Additionally, it was observed that a moderate inclusion of TS can enhance evaporation process. Keywords : Mixture design, Tannery Sludge (TS); Clay bricks ; Evaporation ; Strength; Water absorption; Shrinkage; Leaching; Energy.

Abstract: Mechanical characteristics, dimensional stability, and bonding strength are all impacted by water sorption in polymer filler materials. The diffusion coefficient (D) of water through polymer composite, should be determined to understand the impact of the deterioration on service life and micro-leakage. In this study, the kinetics and properties of water absorption by short-term immersion in room-temperature plantain fibre reinforced epoxy bio-composites (PFRC), were studied. 5, 10, 20, and 30 percent, plantain fiber (PF) volume fractions of bio-composite specimens were made. Due to the high cellulose content of natural fibers (NF), the percentage of moisture absorption grew as the PF volume fraction increased. The mechanism and kinetics of PFRC's water absorption were found to follow the Fickian diffusion mode and had the propensity to behave in the Fickian mode.

Abstract: Biodegradable films demand increases due to the awareness of the environmental effects of synthetic plastics. However, biodegradable films based on starch have high water sensibility and poor mechanical properties. This led to an interest among the scientist in improving the properties of biodegradable films. The objectives of this study were to investigate the effect of lotus root starch content on the water solubility, water absorption, water vapor permeability and biodegradability of cassava bioplastic films. The lotus root starch was added at 10%, 20%, 30%, 40% and 50% of cassava starch. The results showed that the water absorption properties decreased by 122% to 21% and the water vapor permeability showed a decreasing trend as the lotus starch content increased. The water solubility increased from 4% to 36% with the increase of lotus starch content and biodegradability increased by 87.5% at 50% of lotus starch content. The results exposed the potential of cassava/ lotus starch bioplastic films for food packaging applications.