Percentage Of Water Absorption Research Articles

Synergy of waste plastics and natural fibers as sustainable composites for structural applications concerning circular economy.

The increasing demand for shelters, depleting natural resources, concern for plastic waste, and rising awareness for the environment have attracted the contemporary world towards the recycling of waste plastics for the development of an alternative and sustainable building construction material. The plastics suffer due to their poor strength which can be successfully overcome by the reinforcement of natural fibers. The work aimed to develop and investigate the properties of natural fiber-reinforced composites for structural applications such as floor tiles and pavements. The composites were developed by utilizing three different types of waste plastics, namely, low-density polyethylene, high-density polyethylene, and polypropylene with the reinforcement of coconut (cocos nucifera) and Tossa jute (corchorus olitorius) fibers. The evaluation of the density, water absorption, compressive strength, and flexural strength was performed. Moreover, three-body abrasive wear performance was investigated under the conditions of different loads and sliding speeds. The wear mechanism was explored by the morphological analyses of the fractured and worn-out surfaces. The composite HDPE80C20 showed a maximum density of 1.603 g/cm3 and minimum percentage of water absorption to 0.2022. Moreover, the composite attained a maximum compressive and flexural strength of 40.10 and 10.04 (MPa), respectively. The ranges for abrasive wear were found to be 0.002375-0.20015 (cm3) and 0.01987-0.39593 (cm3) under the considered conditions of loads and sliding speeds, respectively. The comparative analysis of the properties suggested the reinforcement of 20 wt% of jute fiber with 80 wt% of high-density polyethylene for the development of composites for structural applications. The study highlighted the potential of waste plastics and natural fibers as value-added products for building construction with relevancy from socio-eco and environmental points of view.

Effect of slag sand as river sand and its influence on compressive strength of the cement mortar

Cement mortar is widely used in all construction activities due to its strong binding and durable properties. Sand is the main ingredient in preparing cement mortar in different ratios from 1:1 to 1: 8 for various elements in construction. As we are facing a shortfall for river sand, an alternate crushed stone as M−sand is used everywhere for river sand. Mining, crushing rock particles, and stone quarrying also have long-term effects on the environment. Industrial effluents from the manufacturing of steel, copper, and coal also possess some aggregates properties, dumping them as waste, leading to disposal challenges & adverse environmental impacts. Hence researchers are trying different ways to minimize waste disposal and address the scarcity of river sand in construction activities. One such trial is attempted in this study to utilize the waste effluent slag sand obtained from the steel industry as a replacement for sand. The experimental investigation is conducted by replacing slag sand in various percentages from 0 to 100% in the ratio of 1:3 cement mortar. A microstructure test was performed on slag sand to check its feasibility compared to M−sand, and the compressive strength of mortar was analyzed at 3, 7, and 28 days of curing. Also, an Ultrasonic pulse velocity test is performed to evaluate the quality of the mortar. Test results revealed that slag sand increases strength with age. But slag sand absorbs more water compared to M−sand, making the mix stiffer. Adding the extra water corresponds to water absorption percentage, and strength increased further at all ages of curing and improved cement mortar quality. Thus, the optimum percentage of slag sand as a replacement for M−sand is 50% in cement mortar. Thereby helping minimize the disposal challenge by producing eco-friendly mortar and reducing the construction cost. This slag sand proves as a sustainable material for futuristic constructions.

Effect of elevated temperature on Portland Pozzolona cement based concrete using Sulphonated naphthalene formaldehyde and Polycarboxylic ether as superplasticizer

The most extensively used structural material in the world for construction purposes is concrete. It has been observed that mineral admixtures like fly ash, rice husk ash, etc., when used in concrete improves its performance at high temperatures, but the role of chemical admixtures at such high temperatures has yet not been investigated. In the current study, experimental research was done to study the role of Sulphonated Naphthalene Formaldehyde (SNF) and Polycarboxylic Ether (PCE) based superplasticizers in concrete at elevated temperatures. Concrete mixes of grade M20, M25, M30, M35 and M40 were prepared with and without superplasticizers. The concrete cube mould samples were heated at elevated temperatures of 100 °C and 200 °C for 1 h and then removed from the oven and cooled to room temperature and further tested for compressive strength. It was observed that lower grade concrete performed better than higher grade at elevated temperatures and for each grade, the mix containing SNF showed an inferior response as compared to the other two mixes at 200 °C. It was also concluded that the PCE based superplasticizer increases the compressive strength at elevated temperatures as well as at room temperature for all grades of concrete. This study also focuses on checking the durability for different grades of concrete with and without superplasticizer via water absorption test. It was concluded that percentage water absorption decreases with increase in grade of concrete owing to higher cement content, and there was no effect of SNF and PCE based superplasticizers on durability of concrete.

Smart waste management perspective of COVID-19 healthy personal protective materials in concrete for decorative landscape pavements and artificial rocks

This paper presents a new method for determining the effect of healthy personal protective material (HPPM) stripes, such as surgical masks, protective suits, and overhead and foot covers, on the durability and physicomechanical characteristics of concrete for use in architectural forms. Because of the current global epidemic caused by coronavirus (COVID-19), the use of HPPM, such as surgical masks, protective suits, and overhead and foot covers, has increased considerably. COVID-19’s second and third waves are currently affecting various countries, necessitating the use of facemasks (FM). Consequently, millions of single FM have been discharged into the wild, washing up on beaches, floating beneath the seas, and ending up in hazardous locations. The effect of stripe fibers on the physicomechanical characteristics of concrete, such as the workability, Uniaxial Compressive Strength UCS, flexural strength, impact strength, spalling resistance, abrasion resistance, sorptivity, Water absorption Sw, porosity (ηe), water penetration, permeability, and economic and eco-friendly aspects, need to be determined. With a focus on HPPM, especially single-use facemasks, this study investigated an innovative way to incorporate pandemic waste into concrete structures. Scanning electron microscope and X-ray diffraction patterns were employed to analyze the microstructures and interfacial transition zones and to identify the elemental composition. The HPPM had a pore-blocking effect, which reduced the permeability and capillary porosity. Additionally, the best concentrations of HPPM, particularly of masks, were applied by volume at 0, 1, 1.5, 2.0, and 2.5%. The use of mixed fibers from different HPPMs increased the strength and overall performance of concrete samples. The tendency of growing strength began to disappear at approximately 2%. The results of this investigation showed that the stripe content had no effect on the compressive strength. However, the stripe is critical for determining the flexural strength of concrete. The UCS increased steadily between 1 and 1.5% before falling marginally at 2.5%, which indicates that incorporating HPPM into concrete had a significant impact on the UCS of the mixture. The addition of HPPM to the mixtures considerably modified the failure mode of concrete from brittle to ductile. Water absorption in hardened concrete is reduced when HPPM stripes and fibers were added separately in low-volume fractions to the concrete mixture. The concrete containing 2% HPPM fibers had the lowest water absorption and porosity percentage. The HPPM fibers were found to act as bridges across cracks, enhancing the transfer capability of the matrices. From a technological and environmental standpoint, this study found that using HPPM fibers in the production of concrete is viable.

Degradation of Carbon Fiber-Reinforced Polymer Composites in Salt Water and Rapid Evaluation by Electrochemical Impedance Spectroscopy.

The electrochemical impedance spectroscopy and weight gain tests were performed on carbon fiber/vinyl ester and carbon fiber/bismaleimide composites in 3.5% NaCl solution to study the electrochemical and water absorption behaviors. The microstructure morphology and the flexural property of the composites in the long-term exposure process were analyzed with the scanning electron microscope and four-point bending tests. The results revealed that after long-time immersion (>200 d), the water absorption of the two composites is less than 0.5%. This has little effect on the microstructural integrity, only with slight damage on the fiber/resin interfaces, but results in a significant decrease (about 84%) in the composite flexural property. The variation of the water absorption percentage shows good consistency with that of the resin capacitance (Qc) and is negatively related to the variation of the resin resistance (Rpo) and the low-frequency impedance (|Z|0.01Hz) of the composites. A good linear relationship exists between the variations of phase angles in the middle-frequency range (0.1-10 Hz) and the |Z|0.01Hz. The phase angle at 10 Hz (θ10Hz) may be suggested as a suitable parameter to rapidly evaluate the performance of carbon fiber-reinforced polymer composites, just like for evaluating the protective performance of polymer-coated metals in the literature.

Effect of fibre orientation and stacking sequence on properties of hybrid composites

A novel combination of Borassus Flabellifer Petiole Fibre/Palmyra Palm Petiole Fibre (PP) and Borassus Flabellifer Leaf Stalk Fibre/Palmyra Palm Leaf Stalk Fibre fibres (LS) bonded by vinyl ester is considered as the natural fibre-reinforced hybrid composites. Three-layered composites with various stacking sequences at 30 wt.% fibre loading were studied. Tensile, impact, and hardness properties exhibit increasing trend for different stacking sequences. A maximum increase of 215.8% tensile strength and 310.5% impact strength was observed in the PPLSPP (90/0/90) specimen. The water absorption percentage showed a peak value of 18% and the hardness enhancement was around 75% for the LSPPLS (90/0/90) sample. The Fourier Transform Infrared spectroscopy was performed and Scanning electron micrographs were performed to show the fibre–matrix bonding.

Synthesis and Evaluation of Eco-Friendly, Ambient-Cured, Geopolymer-Based Bricks Using Industrial By-Products

Geopolymer-based sustainable red mud bricks (SRMBs) were cast using industrial by-products under ambient curing. The ingredients used were red mud, fly ash, ground granulated blast furnace slag and alccofine, along with quarry dust and alkali activators as binders. This paper briefly presents the characterization, strength and durability studies conducted on SRMBs. The optimization techniques were used to fix the right mix proportions. The optimized mix proportion was identified as R45F40G10A05: 45% red mud, 40% fly ash, 10% ground granulated blast furnace slag and 5% alccofine. The compressive, flexural and split tensile strength of the ambient-cured specimens after 28 days were observed as 35.38 MPa, 6.4 MPa and 1.67 MPa, respectively. The results were analysed and validated by the finite element method using Analysis of Systems (ANSYS) software. The percentage of water absorption in the SRMBs was less than 6%, and it was an entirely efflorescence-free product with a pleasing appearance and colour. Fifty percent of the targeted compressive strength was acquired after three days of ambient curing. SRMBs are a green product casted by encapsulating industrial by-products into a functional building element. Thus, SRMBs are a suitable and alternative product to conventional clay burnt bricks.

A novel preparation and characterization of electroless NiP/MWCNT composite coated UHMWPE fabric in terms of wettability, electrical conductivity, thermal stability and breaking load resistance

Poor wettability results in fragile bonding between the ultra-high molecular weight polyethylene (UHMWPE) fabric and matrix of the composites. To overcome this issue, the present study proposes a novel approach for the deposition of electroless nickel-phosphorus (NiP) and nickel-phosphorus/multi walled carbon nanotube (NiP/MWCNT) coating on the surface of UHMWPE. The influence of coatings on the morphology, phase structure, crystal size, functional groups, surface roughness, wettability, water absorption property, electrical conductivity, thermal stability, peeling load and breaking load of UHMWPE fabric are detailed. After MWCNT was reinforced, the cauliflower structure reported for NiP coated UHMWPE (NiP-UHMWPE) was altered for NiP/MWCNT-coated UHMWPE (NiP/MWCNT-UHMWPE). The crystal size of NiP has slightly increased to 1.307 nm for NiP/MWCNT-UHMWPE from 1.22 nm of NiP-UHMWP. The contact angle of NiP-UHMWPE (84.36°) was relatively lower than the NiP/MWCNT-UHMWPE (92.46°) and UHMWPE (102°), due to the formation of more nickel globules in the surface of NiP-UHMWPE. Though the wettability was high for the NiP and NiP/MWCNT coating, the water absorption percentage has not increased for NiP-UHMWPE and NiP/MWCNT-UHMWPE. The electrical conductivity was improved for NiP/MWCNT-UHMWPE after the reinforcement of MWCNT. The breaking load of the NiP and NiP/MWCNT coated UHMWPE fabric improved by 6.24% and 12.11% respectively. The more detailed study in terms of functional group, crystal structure, compounds, electrical conductivity, thermal stability, peeling load, and tensile failure analysis of coated UHMWPE fabric are reported in this article.

Crystalline structure of cellulose in wood after chemical modification using cyclic acid anhydrides (maleic and succinic)

The chemical modification of wood can be directed to improve various properties, e.g., the dimensional stability, hardness properties, and/or durability properties, against weathering. In this study, a Romanian softwood species Abies alba Mill. was treated and chemically modified using two cyclic acid anhydrides, i.e., maleic and succinic, to improve its interfacial properties relative to unmodified wood. Structural changes, with focus on the evolution of crystalline part in wood after chemical modification, the water absorption, and the water repellent efficiency, were determined. Maleic anhydride exhibited a lower reactivity towards wood substrate than succinic anhydride, presumably because of their different chemical structure (maleic anhydride is very sensitive to the presence of water). It was found that the percentage of water absorption was diminished, primarily after the succinic anhydride treatment. The chemically modified wood was characterized via Fourier transform-infrared spectroscopy and wide-angle X-ray diffraction methods. The crystalline part from wood structure was evidenced in relation to the employed anhydride in chemical modification approach.

Synthesis of Metakaolin Based Alkali Activated Materials as an Adsorbent at Different Na2SiO3/NaOH Ratios and Exposing Temperatures for Cu2+ Removal.

Water contamination is a major issue due to industrial releases of hazardous heavy metals. Copper ions are among the most dangerous heavy metals owing to their carcinogenicity and harmful effects on the environment and human health. Adsorption of copper ions using alkali activated materials synthesized through the polycondensation reaction of an alkali source and aluminosilicates is the most promising technique, and has a high adsorption capability owing to a large surface area and pore volume. This research focuses on the effect of the alkaline activator ratio, which is a sodium silicate to sodium hydroxide ratio. Various exposing temperatures on metakaolin based alkali activated materials on a surface structure with excellent functional properties can be used as adsorbent materials for the removal of copper ions. A variety of mix designs were created with varying sodium silicate to sodium hydroxide ratios, with a fixed sodium hydroxide molarity, metakaolin to alkali activator ratio, hydrogen peroxide, and surfactant content of 10 M, 0.8, 1.00 wt%, and 3.0 wt%, respectively. Most wastewater adsorbents need high sintering temperatures, requiring an energy-intensive and time-consuming manufacturing process. In this way, metakaolin-based alkali activated materials are adsorbent and may be produced easily by solidifying the sample at 60 °C without using much energy. The specific surface area, water absorption, microstructure, phase analysis, functional group analysis, and adsorption capability of copper ions by metakaolin based alkali activated materials as adsorbents were evaluated. The water absorption test on the samples revealed that the sodium silicate to sodium hydroxide 0.5 ratio had the highest water absorption percentage of 36.24%, superior pore size distribution, and homogeneous porosity at 60 °C, with a surface area of 24.6076 m2/g and the highest copper ion uptake of 63.726 mg/g with 95.59% copper ion removal efficiency at adsorption condition of pH = 5, a dosage of 0.15 g, 100 mg/L of the initial copper solution, the temperature of 25 °C, and contact time of 60 min. It is concluded that self-supported metakaolin based alkali activated material adsorbents synthesized at low temperatures effectively remove copper ions in aqueous solutions, making them an excellent alternative for wastewater treatment applications.

Influence of alkalisation and eggshell particles on mechanical, thermal and physical properties of rattan-bamboo fibre reinforced hybrid polyester laminated composite

ABSTRACT The main purpose of this research is to observe the effect of alkalisation of rattan, bamboo fibre, and eggshell particles addition in the fabrication of hybrid polyester laminated composite. A 5% NaOH treatment of fibres was conducted, and 5% eggshell particles was added to the composite. The FTIR analysis was done to reveal the presence of nanol, and thermal stabilities were evaluated by TGA, DTG and DTA. Furthermore, water absorption and biodegradability of the composite were also investigated. Mechanical properties were tested with compatible ASTM standards. The 5% NaOH treated 30 wt.% fibre- loading enhanced the tensile strength, flexural strength, impact strength, and hardness by 9%, 2%, 7%, and 4%, respectively compared to the raw composites. On the other hand, the addition of 5% eggshell particles decreased the tensile strength, flexural strength, impact strength, and hardness of the raw 30 wt% fibre-reinforced composite by 5%, 4%, 3%, and 2%, respectively In addition, the raw 30 wt% fibre-reinforced composite has the highest biodegradability, and water absorption percentage than the alkali-treated and eggshell added fibre-reinforced composite. The raw 30 wt% fibre-reinforced composite has dictated over the alkali-treated and eggshell added fibre-reinforced composite in terms of thermal stability.

Effect of three MWCNTs-COOH (chiral, zigzag and armchair) on the mechanical properties and water absorption of cement-based composites

In this study, multi-walled nanotubes (MWCNTs) functionalized with carboxyl group are used as additives with different morphologies of chiral, zigzag and armchair to investigate the effects of three MWCNTs on the mechanical and water absorption properties of cement-based composites. Accordingly, two different concentrations of 0.05 and 0.1 wt.% of MWCNTs are incorporated in the cement paste with a water-to-cement ratio of 0.4. The results indicate that the chiral sample for 0.05 wt.% at the age of 7 and 28 days and 0.1 wt.% at 7 days, and the armchair sample with 0.1 wt.% at the age of 28 days have the highest compressive strength. The flexural strength at 7 and 28 days show that the chiral MWCNT composite has the greatest increase in strength for both 0.05 and 0.1%. The ranking of water absorption is chiral < zigzag < armchair < PC and armchair < chiral < zigzag < PC for 0.05 and 0.1 wt.% MWCNT at 28 days, respectively. The results, thus, show that the lowest percentage of water absorption is obtained by 0.05% chiral MWCNT-COOH and 0.1% armchair MWCNT-COOH at the age of 28 days. The effect of bridging, connecting MWCNTs and hydration products provided by MWCNTs-COOH, is, thus, confirmed by SEM.

Effect of beeswax on the physical and mechanical properties of solution cast poly(butylene adipate co-terephthalate)/thermoplastic starch/beeswax films

Biodegradable films of poly(butylene adipate co-terephthalate) (PBAT)/thermoplastic starch (TPS)/beeswax have been prepared by solution casting method. Beeswax has been used as a hydrophobic content to improve the water barrier properties of the films. The prepared films have been characterized for tensile properties, morphology, water absorption, and water vapor permeability. Tensile strength of the films initially increases with the addition of beeswax and then decreases with increase in beeswax content. Tensile strength of film with 0.5 wt% of beeswax is about 213% greater than the film without beeswax. Water absorption percentage of films decreases gradually from 18.7% in film without beeswax to 0% with an increase in amount of beeswax, i.e., 0.5wt%, 1wt% and 2wt% due to the hydrophobicity of beeswax. Water vapor permeability of these films reduces upon increasing the amount of beeswax.

Mechanical And Durability Behaviour Of GGBS, M-sand Based Concrete With Varying Percentages Of Two Crystalline Admixtures – An Experimental Study

This paper presents various investigations into the mechanical and long-term longevity parameters of concrete made with ground granulated blast slag (GGBS). In this experimental study, GGBS is used as a 30% substitute for cement, and two types of crystalline admixtures (CA’s) with different proportions of 0%, 0.5%, 0.75%, and 1% were added to the mix. Cubes and Cylinders were casted by mixing Mcrete and Master Pel 760 crystalline admixtures for two grades, M25 & M35 and left for curing period of 28 days. Test methods includecompressive strength, split tensile strength, Rapid Chloride Permeability test (RCPT), Sorptivity, Percentage of water absorption, Percentage of Voids and carbonation. The test results showed that both CA’s with GGBS at 0.75% produced better results and also significantly increased compressive strength by 12.08% for M25 grade and 16.04% for M35 grade, and tensile strength by 19% for M25 grade and 30.59% for M35 grade. Similarly, a decrease in percentages of 14.7 & 16.9 in RCPT, 8.52 & 11.19 in water absorption, and 11.34 & 10.01 in voids was observed in both M25 and M35 grades. Finally, Master Pel 760 has shown better performance than Mcrete Crystalline admixture. So, the above two CA’s has the potential to increase the durability and decrease the permeability of concrete buildings, particularly those exposed to corrosive conditions.

Exploitation of plastic bags in roadway blocks

Plastics are an increasingly important component of urban solid waste. The disposal of waste materials, such as used plastic bags, has become a major issue. The vast amount of waste plastic bags collected in the twenty-first century has posed significant challenges for their disposal. The amount of waste plastic in the home is substantial and growing. Our results indicate cement blocks are ideal for laying and finishing pathways and streets because they are easy to lay and finish. This study was carried out on experimenting the substitute materials in the mixture of cement blocks a component of building materials which is normally manufactured using the mixture of cement, fine aggregate and water, following a certain ratio. A series of three different percentages of plastics bags were added with the mix and certain quantities were replaced by quarry dust instead of Fine aggregate. Tests were done on the blocks to study its compressive strength, split tensile strength the water absorption percentage and acid test. Both the test compressive and split tensile tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the result a good indication is that the blocks can be produced by replacing the cement and fine aggregate with utilizing the plastic for and effective way of 1:1 and 1:2, with 10& 20% replacing with quarry dust having strength 10.7 and 9.5 N/mm 2 respectively Which is 165 more than the conventional type of blocks. Similarly the water percentage is also nil and very marginal in the same proportions. The decrease in weight is existed in all the samples tested the result is equal in all mix compositions. This is uniform rate implies block undergo certain abrasion. Conclusions were drawn for utilising the above composition in a suitable non structured places and minimizing the plastic waste.

Characterization of Buleleng clay and improvement of its ceramic properties

Purpose. The research focuses on the improvement of local clay-based ceramic pottery bodies from Alas Angker in Buleleng Regency in Bali. The main purpose is to utilize the clay which meets the standards of ceramics such as smooth and hard earthenware, especially to reduce its water absorption property. Methods. Firstly, the clay is analyzed for its physical and chemical composition. Two ceramic body formulations are made using the clay with the BWNAA1 and BWNAA2 codes. The specimens are measured in terms of clay ceramics properties including plasticity, dry shrinkage, firing shrinkage and water absorption. The cracked ceramic products are also analyzed for a comparison. Findings. The ceramic properties show similar results, except for the water absorption percentage. The BWNAA2 code formulation has lower water absorption rate by 10.8% and meets the requirements for the type of smooth and hard earthenware body in compliance with the national standard SNI:7275-2018. The water absorption rate is about half of the existing products, which is effective in avoiding the problem of cracks. Originality. Comparison of the existing ceramic products and specimens made in this study shows a significant difference in water absorption and crack growth. Adding a certain amount of kaolin, feldspar, ball clay and quartz sand has significantly reduced the water absorption rate of ceramic bodies. Practical implications. This research can be a potential solution to increase the quality of ceramic pottery products in the vicinity of Buleleng Regency which use the clay of this kind.

Influence of modification of aged spruce wood by in situ polymerization with ethyl methacrylate and methyl acrylate and paraloid B72 on color and water absorption

Influence of modification of aged spruce wood by in situ polymerization with ethyl methacrylate and methyl acrylate and paraloid B72 on color and water absorption. Wood is hydrophilic in nature, which creates problems such as dimensional instability and susceptibility to biological degradation. By using chemical modification, wood can be refined into new products with improved properties. Such a combination of wood and polymer is called a wood-polymer composite (WPC). The presented work compares the modification of aged wood by two methods. In situ polymerization with ethyl methacrylate and methyl acrylate with modification with Paraloid B72 solution. The determinants of the modifications carried out are percentage weight gain (WPG), color change and water absorption. Unmodified wood aged and unaged were the control samples. Also unaged and modified wood samples were prepared to compare results. The greatest change in color intensity and total color difference after the aging process was recorded for samples modified with Paraloid B72, and after UV light treatment - modified by the in situ polymerization. The in situ-modified samples had the lowest water absorption among aged samples, and Paraloid B72-modified samples had the lowest water absorption among unaged samples. The highest WPG was obtained from the aged samples modified by the in situ polymerization.

Concrete Performance Produced Using Recycled Construction and By-Product Industrial Waste Coarse Aggregates.

Concrete is classified as a multi-composite material comprising three phases: coarse aggregate, mortar, and interfacial transition zone (ITZ). Fine and coarse aggregates occupy approximately 70-85% by volume, of which coarse aggregate typically constitutes more than two-thirds of the total quantity of aggregate by volume. The current study investigates the concrete performance produced using various recycled construction and by-product industrial waste coarse aggregates. Six types of coarse aggregates: manufactured limestone, quartzite, natural scoria, by-product industrial waste aggregate, and two sources of recycled concrete aggregates with densities ranging from 860 to 2300 kg/m3 and with different strength properties were studied. To determine the coarse aggregate contribution to the overall concrete performance, lean and rich concrete mixtures (Mix 1 and Mix 2) were used. Mix 1 (lean mixture) consisted of a ratio of water to cement (w/c) of 0.5 and cement content of 300 kg/m3, whereas a higher quantity of cement of 500 kg/m3 and a lower w/c ratio of 0.3 were used for Mix 2 (rich mixture). The results showed that while the compressive strength for different aggregate types in Mix 1 was comparable, the contribution of aggregate to concrete performance was very significant for Mix 2. Heavyweight aggregate produced the highest strength, while the lightweight and recycled aggregates resulted in lower mechanical properties compared to normal weight aggregates. The modulus of elasticity was also substantially affected by the coarse aggregate characteristics and even for Mix 1. The ACI 363R-92 and CSA A23.3-04 appeared to have the best model for predicting the modulus of elasticity, followed by the ACI-318-19 (density-based formula) and AS-3600-09. The density of coarse aggregate, and hence concrete, greatly influenced the mechanical properties of concrete. The water absorption percentage for the concrete produced from various types of aggregates was found to be higher for the aggregates of higher absorption capacity.

Hydromechanical Characterization of Raw Earth Mortar – Stabilizing Cement and Lime

Abstract Earth-based mortars are again taking their place as building materials for plastering, rendering and repairing earth walls, not only in a sustainable context but also in terms of efficiency. Nevertheless, scientific understanding of these mortars is still scarce. This present paper reports on an experimental study, conducted at the laboratory of the university center of El-Bayadh, concerning the study of the hydro-mechanical characteristics of mortars based raw and stabilized earth. In doing so, mortars prepared with clay-sand soil, treated with cement (C) (6%, 8% and 10%), lime (L) (4%, 6% and 8%) and mortars treated with both binders (4% C+2% L, 5% C +4% L, 8% C+6% L) taking into account control mortars of raw earth, are investigated. Compressive and tensile percentage strengths, total absorption, and swelling are determined. Therefore, the obtained results in the case of total absorption test, showed significant erosion in the mortars specimens weakly stabilized with cement and those without added stabilizer. Indeed, it was observed during the swelling test that the mortars specimens weakly stabilized with cement were fragile to the erosive water and showed deterioration, especially at the edges. Furthermore, increasing the cement content from 6% to 10%, the water absorption percentage was reduced by 30%. It appears that the composition that led to a better behavior towards water is the mixed combination (8% cement + 6% lime). However, stabilization with cement confers a higher strength compared to lime powder. In fact, the maximum resistances were obtained for high cement dosages (8 and 10% respectively) and the 4% lime dosage.

Mechanical and physical properties of unsaturated polyester reinforced kenaf core fiber with hybrid cellulose nanocrystal (CNC) and graphene Nanoplatelet(GNP) nanofillers

In this study, the exploration of kenaf core fiber (KCF) was done by incorporating into unsaturated polyester (UPE) as to keep the environment sustain and also due to its potential properties which are good mechanical properties, low cost and importantly massively abundant. The hybridization technique also were applied with the incorporation of total loading level of 3 wt% Cellulose nanocrystal (CNC) and graphene nanoplatelet (GNP) into UPE-KCF bio-composite as to support and provide better performance of UPE bio-composite. In revealing the effect of nanofillers utilization towards mechanical and physical properties of UPE-KCF bio-composite, the fabrication of UPE-KCF/CNC/GNP bio-composite were successfully done by using hand lay-up technique and hot compression moulding. The samples were characterized through tensile and flexural test for mechanical analysis and water absorption for physical analysis. Morphology characterization also was done to support the result. The results showed the incorporation of KCF had contributed for the slightly improvement in tensile modulus while both inclusion of nanofillers help the single reinforcement bio-composite to enhance flexural strength and modulus up to 48.2% and 84.21% respectively. The addition of 2 wt% GNP also positively influence physical properties showed by the least percentage of water absorption.