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The life span of a structure depends on the strength and durability of concrete. The use of mineral admixtures in concrete plays a major role in achieving higher strength and durability characteristics. At present nanotechnology is being used in the concrete to decrease the permeability of concrete and also to extend the life service. Nanomaterials are extremely small in size which when used in concrete, improves the strength and reduces porosity. This study gives the characteristics of concrete when Nanosilica (NS) and Multi-Walled Carbon Nanotubes (CNT) were added to it. Manufactured sand was used as a fine aggregate in replacement of natural river sand. For conventional and nano-concrete, the durability characteristics were assessed by conducting water absorption, sorptivity, accelerated corrosion, and carbonation tests after 28 days and 90 days of curing. The formation of hydration products was studied through microstructural analysis by SEM and XRD. Closely packed concrete was achieved with the addition of NS and CNT. The permeability and porosity were reduced for nano-concrete because of the filler effect of nanomaterials.

Carbon Nano Tubes are strongest known materials known till now which can be ideally used in conventional concrete to tailor its functionalities. As water cement ratio governs the strength, serviceability and durability of concrete so its important to know the effect of Carbon Nano Tubes on basic properties of concrete. In order to analyze fresh and hardened properties of conventional concrete 0.5% Carbon Nano Tubes by weight of cement was incorporated in concrete mixes having water cement ratio 0.40, 0.45, 0.48.0.50 and 0.50. It was observed at 0.45 water cement ratio compressive, split tensile and Moment of resistance was greater by 8.89%, 28.9% and 5.33% respectively in comparison to Reference mixes while workability diminued by 38.40% and water absorption decreased by 0.03%. Also Coefficient of relationship R2 for water absorption and water-cement ratio of Carbon Nano Tube reinforced concrete was found as high as 0.97. Scanning electron microscopic analysis revealed dispersion of Carbon Nano Tubes and their bridging effect.

Oil palm shell (OPS), one of the most abundantly produced solid bio-wastes in Southeast Asia, is yielded by crushing the oil palm kernel during palm oil extraction in the palm oil mills. Approaches have been devoted to developing the use of OPS as reinforcing filler in polymer composites to enhance the functional properties of composites. For OPS to be effective for reinforcing materials, its role and beneficial effects on the improvement of composites’ properties need to be investigated. However, not many studies have discussed the potentials of incorporating OPS in thermoplastic and thermoset polymer composite applications. This paper summarises the enhancement of composite characteristics, including physical, mechanical, thermal, water barrier and biodegradability properties. Properties of OPS that make it a good candidate as a reinforcing filler, such as tensile strength, impact strength, elongation, Young’s modulus, morphological and water absorption, are discussed in detail. In addition, the application of its derivative, challenges, and outlook are also discussed.

In this study, we evaluated the characteristics of five commercial resin composites used for provisional restorations. The inorganic filler contents of the resins were measured, and three-point bending, wear, surface hardness, water absorption, and staining tests were performed. The specimens underwent additional three-point bending tests after water storage and undergoing thermal stresses at 5°C and 55°C (10,000 cycles). Data were analyzed using one- or two-way analysis of variance and Bonferroni post-hoc tests. Pearson's correlation coefficient was used for pairwise comparisons. Each resin composite presented with different mechanical properties, based on variations in the inorganic filler content. The flexural strength of each resin composite was significantly decreased after water storage. There has a positive correlation between flexural strength and dynamic hardness but a negative correlation between flexural strength and maximum wear depth. The types and contents of the inorganic fillers, the composition of the monomer in the resin matrix, and the addition of plasticizers can affect the properties of the material.

This study focused on the optimization of the production conditions of an ultrahigh expanded perlite lightweight aggregate-filled fly ash-based geopolymer composite and the determination of its product properties. The geopolymer matrix was synthetized using mechanically activated fly ash and an alkaline solution. In a systematic series of experiments, the effect of expanded perlite (EP) content, the compaction pressure and the compaction time on the mechanical properties of the lightweight composite were investigated. In the case of the optimal production conditions, the composites were characterized in terms of physico-mechanical properties, water absorption and microstructure. The composites produced under optimal conditions had an average uniaxial compressive strength of 246 kPa and density of 534 kg/m3 at 80% by volume EP content, and 264 kPa and 221 kg/m3 at 95% by volume EP content. Both the FT-IR spectroscopy and scanning electron microscopy results proved the formation of main geopolymerization reaction products in the matrix of the composite, as well its reaction with the lightweight aggregate.

In this work, the hybrid natural fiber composites (NFCs) were prepared using a standard hand lay-up technique from Banana fiber (B), Sisal fiber (S), and sawdust (SD) with different compositions viz. S-I (B 60%–S 20%–SD 20%), S-II (B 80%–S 5%–SD 15%) and, S-III (B 80%–S 15%–SD 5%) bounded with 80% epoxy resin LY556 and hardener LY953 in the 4:1 ratio as per ASTM standards. All the specimens were made with proper composition of 20 wt% of reinforcing materials and 80 wt% of the matrix material. The mechanical (tensile strength, compressive strength, flexural strength, and impact strength) properties and Brinell hardness of prepared specimens were conducted according to ASTM standards. The tensile, compressive, flexural, and impact strength, as well as Brinell hardness of the prepared NFCs, were found to increase with the increase in sawdust content in the epoxy matrix. Further, an improvement in the water absorption property was registered with the increment of sawdust content in the banana-sisal/epoxy composite. The value of dielectric permittivity increased while that of tangent loss decreased with increasing sawdust content. The improved mechanical, dielectric as well as water absorption properties and better Brinell hardness, foreshadow the industrial promises of the present NFCs a better alternative for synthetic fiber-reinforced composite materials.

According to the latest studies, nanoparticles are the best additive materials to improve concrete's mechanical properties. Among these nanoparticles, Carbon Nanotubes (CNTs) are famous for their extreme tensile strength and flexibility. These particles can be used as a reinforcement to increase the mechanical properties of concrete. In the present study, the effects of using CNTs with different dosages were investigated on structural lightweight concrete’s mechanical properties. Structural Lightweight Expanded Clay Aggregates (LECA) were used in the mixture of Structural Lightweight Concrete (LWC) as a substitute for coarse aggregates. Along with LECA, CNTs as a partial replacement for cement with varied weight ratios were added to the lightweight concrete (0.02, 0.1, and 0.3 percent of cement weight). The effects of carbon nanotubes on fresh concrete performance, water absorption, compressive strength, tensile strength, and flexural strength of 7- and 28-day lightweight concrete were carried out. The results indicate that the presence of 0.02% of cement weight of CNTs increased compressive strength, tensile strength, and flexural strength of the 28-day-old lightweight concrete up to 29%, 44%, and 26%, respectively. Moreover, it reduced the water absorption of lightweight concrete by 28.3%. Utilizing more content of CNTs resulted in less mechanical properties. Having done experimental tests, nanoparticles and cementitious materials bonding have been visualized by Scanning Electron Microscopy (SEM) device.

Microbial self-healing is an innovative technology which repairs cracks in concrete by precipitation of calcite. The main focus of our research study was focused on evaluating the performance of synthesized microbial agent with Bacillus sphaericus (spore forming urelotic strain) of cell dosage 105 cells/ml in repairing cracks in fly ash concrete. The bio-based agent is added to cracks in fly ash concrete. The effectiveness of prepared bio- based agent in repairing the cracks in concrete was assessed by comparing with non-based agent prepared with cement, sand and water. The mechanical and water absorption property are evaluated. The compressive strength and water absorption of micro-repaired concrete was found to increase by 10% and 6 % in comparison with non micro repair concrete. Scanning electron microscope analysis of concrete samples was done to confirm formation of calcite. The analysis showed formation of calcite particle near the microbial cells. This confirms that the improvement in properties of concrete is due to formation of calcite particles due to biomineralization process. Use of Micro-based agent would lead to environmental and economical benefit. Over all the maintenance and repair cost could be reduced and also play a role in reducing green house gas emissions and help to develop sustainable concrete.

Nowadays concrete and mortar demand as construction materials has been surged in market due to the exorbitant augmentation of the construction industry. Cement and fine aggregates (like river sand, pit sand etc.) are consumed in a large quantity to produce the mortar for various uses. In this venture, the cement and natural sand is been replaced with the soda-lime glass and the properties of mortar has been characterized for this replacement. Various proportions adopted for the cement replacement by weight 0–20% and natural sand replacement by weight are used 0–30% at 5% interval. The influence on the workability, density, water absorption, mechanical strength, drying shrinkage and Alkali Silica Reaction (ASR) expansion are assessed. Outcome of the investigation reveals that the dose of soda-lime glass replaced with cement and natural sand plays an important role to determine characteristics of cement mortar. Mortar made with Glass powder (GP) at 15% replacement with cement and Glass sand (GS) at 25% replacement with natural sand have highest mechanical strength. Water absorption and density reduced by using soda-lime glass. Drying shrinkage mitigate by using waste glass. ASR expansion has reduces due to smaller particle size of glass. The pores refinement and porosity decrement occurs due to the calcium hydroxide (Ca(OH)2) and glass powder reaction, this is a pozzolanic reaction that produces calcium silicate hydrate (C-S-H) gel.

Because of their high strength-to-weight ratio, composites outperform traditional materials. Natural fibers are increasingly being used in composites due to environmental concerns. Their hygroscopic character, on the other hand, has a negative impact on the mechanical properties of the composites. The need to analyses the water uptake characteristics of natural fiber hybrid composites has arisen as a result of composites' use in decking, flooring, and outdoor facilities. The objective of this paper is to study the water absorption behavior and observed that banana/glass fiber composite keeps on increasing. The conclusion is that banana fiber absorbs more water than kenaf/glass fiber composites, and there are numerous causes for trapping of natural fiber water consumption.

Mostly, agricultural residues and fibers are incinerated or dumped into the land after cultivation. Disposal of these waste not only occupy more useful space in land but also spoiled energy resources. It causes pollution to the environment, release of greenhouse gases, etc. Lignocellulosic fibers are rich in cellulose which is abundant in nature. In this work, Banana fiber which was extracted from the bast of the plant is used to make an alternate for synthetic fibers. The polyester based composites were manufactured by with different weight concentration of fibers from 1 to 10%. Tensile and water absorption values of composites were conducted as per the ASTM standards. When the fiber addition increases, water absorption properties also increased due to the characteristics of lignocellulose fibers. From the results, it was understood that the obtained composites can be used in various commercial and bio medical application.

Environmental benefits and amazing performance can be obtained by utilizing palm oil fibres and kenaf fibres which illustrate colossal potential in fibre reinforced composites. An investigation has been made to determine the effects of alkaline treatment on water absorption and swelling behaviour of palm oil fibre composites as well as kenaf fibre composites. Untreated and treated natural fibres and were prepared in random orientation with different volume fraction of palm oil fibres and kenaf fibres; 30%, 40%, and 60. All the treated fibres were treated with 1 w/v% and 5 w/v% of sodium hydroxide concentration. Water absorption test was performed by immersing the sample in the distilled water periodically measuring the sample weight. Thickness swelling test was carried out by measuring the thickness of the specimens before and after soaking in the distilled water within certain period of time. All specimens were observed under Scanning Electron Microscope (SEM) to study the fibre morphology. TPOF_30_5SH achieved the least percentage of water absorption (1.44%) when it was compared with the UPOF_30 and TPOF_40_1SH. UPOF_60 shows the highest percentage of thickness swelling (8.96%). TPOF_30_5SH and TPOF_40_5SH show reduction of water absorption when they were compared with UPOF_30 and UPOF_40 respectively. All the treated kenaf fibre composites with 5 w/v% sodium hydroxide concentration such as TKF_30_5SH, TKF_40_5SH and TKF_60_5SH show improved result of thickness swelling. Materials covering the surface of palm oil fibres and kenaf fibres were more effectively removed with 5 w/v% sodium hydroxide than by treatment with 1 w/v% sodium hydroxide while observing under SEM.

This paper investigated the effect of rice husk ash (RHA) on chloride permeability, water absorption, and permeable pore space of cementitious mortar. It was observed that the permeability, water absorption, and permeable pore spaces of mortar mixtures having rice husk ash as partial replacement of cement decreased as the amount of rice husk ash increased while the compressive strength increased. The reduction in chloride permeability, water absorption, and permeable pore space ranged between ∼3 to ∼52, ∼2 to 10%, and ∼2% to 18% with 4% to 12% RHA dosages without RHA mixture. In addition, linear co-relation exists between water absorption and permeable pore space and permeable pore space and charge pass with a coefficient of correlation of 0.93 and 0.90, respectively; quadratic polynomial co-relation exists between compressive strength and water absorption and compressive strength and permeable pore space.

This study focus on the physical characterization of short roselle fibre polymer composites. Short roselle fibre composites with 10%, 20%, 30% and 40% fibre content by weight were produced using the hand lay-up technique. Composite’s physical properties like density, void content and water uptake capacity were obtained as per ASTM standards. The void content of the composites ranges from 1.28 to 6.71%, which is quite low for short and randomly oriented composites. The saturation in water uptake was observed after 7 to 8 days of water immersion. The water uptake capacity of the roselle fibre composites increases with an increase in fibre content. It indicates the composites with the lower fibre content yield a higher resistance to water absorption.

Natural fibres now a days replacing the conventional structural materials such as Aluminium, steel, wood etc. with their excellent weight to strength ratio and with their high mechanical properties. In this present investigation hybrid composites were fabricated using Hand layup process using the natural fibres such as Banana, Coconut, Jute and Cotton fibres reinforced with Polyethylene at different weight proportions of 5, 8, 10, 12, 15, 18, 20 wt%. Tests such as water absorption, flexural rigidity, tensile, hardness and few other mechanical tests were conducted on the hybrid natural fibre reinforced composites. Among the hybrid composites the coconut fibre with 20 wt% and banana fibre with 18% shows high tensile strength with 56.4 N/mm2 and 54 N/mm2 and flexural strength. Water absorption is less in the hybrid composite with coconut and cotton fibres as reinforcements and gains mass of 5gm and 7gm.

Ultraviolet (UV) radiation is one of the most common methods for sterilizing materials with suspected biological warfare agent contamination. In this study, UV laser sterilization of ceramic tiles was investigated as a method for destroying Bacillus atrophaeus spores. The effects of UV irradiation were evaluated as a function of water absorption (porous and vitrified), tile color (black and white), and surface brightness (matte and glossy). Spores were loaded onto the surface of each tile and irradiated with a 266-nm UV laser. The irradiated spores were then removed by scraping with a razor blade and cultured in an agar plate for 24 h. The sterilizing effects of the UV laser were greater on the vitrified (group BIb) tiles than on the porous (group BIII) tiles. In addition, sterilization was more effective on white and matte tiles than on black and glossy tiles, respectively.

In order to avoid the energy consumption of dewatering and dust pollution in the preparation of non-sintered lightweight aggregates from dredged sediment, a new low-dust process of preparing non-sintered extruded wrap-shell aggregates (TH-WSLAs-W) by extrusion granulation is proposed and applied to produce TH-WSLAs-W baking-free bricks (TH-WSLAB-W). The basic physical properties (cylinder compressive strength, bulk density and water absorption) and microstructure of TH-WSLAs-W was explored. It shows that the curing agent will form a hydrophobic gel film around the sediment particles and form a network structure, which enhances the cylinder compressive strength (6.7 MPa) and frost resistance of TH-WSLAs-W. In addition, the interfacial transition zone among TH-WSLAB-Ws was studied by scanning electron microscope. It found that the micropore structure endow the TH-WSLAs-W with excellent water absorption and drainage property, promoting the hydration of cement, promising the integration of aggregate and cement, and its compressive strength reaches 20.5 MPa.

Background: Buildings in high altitude region often face low pressure and low humidity service environment, which has a great impact on the mechanical properties and durability of cement-based materials. Objective: In this paper, the effects of nano-silica (NS) on the strength and water absorption of cement mortar exposed to the low pressure and low humidity environment were studied. Methods: Mechanical properties (compressive strength and flexural strength) and durability (water absorption) were measured. And the hydration degree of cement was tested to assist analysis. Results: The flexural strength of mortar decreased and the compressive strength increased slowly after 28 days of exposure under low pressure and low humidity environment. Especially, the introduction of 1% NS could reduce the compressive strength loss and flexural strength loss of mortar under low pressure and low humidity environment. It was also found that the water absorption of the mortar in low pressure and low humidity environment was related to the tortuous degree of the pores inside the specimen. Conclusion: The introduction of 1% NS contributed the most to the mechanical properties (compressive strength and flexural strength) and durability (water absorption) of cement mortar.

Present study aims to explore the effect of sintering temperature and dwelling time on the characteristics and morphological structure of lightweight aggregates made from dry sewage sludge and waste glass powder. The mixtures were sintered at temperatures from 1100 °C to 1200 °C at a heating rate of 10 °C/min with a dwelling time of 10, 20, and 30 min to produce lightweight aggregate samples. The thermophysical behavior of the mixtures and the physic-mechanical properties (including water absorption, particle density, and compressive strength) of the obtained lightweight aggregates were studied. The microstructure of the lightweight aggregates was also analyzed using X-ray micro-computed tomography. Results indicate that increasing the sintering temperature or extending the dwelling time will reduce the particle density and compressive strength of lightweight aggregates. Moreover, the sintering temperature and dwelling time show a considerably influence on the pore structure of lightweight aggregates, which is strongly related to the physical characteristics of the lightweight aggregates. The lightweight aggregates obtained at optimized sintering temperature of 1180 °C with an optimal dwelling time of 10 min show water absorption of 1.01%, particle density of 0.78 g/cm3, and compressive strength of 7.10 MPa, thereby meeting the standard requirement of GB/T 17431.2–2010.

The disposal of waste vehicle tires is an environmental and health problem, as their recycling is very difficult. One of the effective ways of recycling is using these tires as partial replacement of Portland cement in construction industry. In this study, a systematic experimental study (by making 810 laboratory samples) is performed on concrete made with finely ground rubber (GR) and metakaolin (MK) as partial replacements of cement to investigate the compressive strength, splitting tensile strength, flexural strength, water absorption, and dry unit weight. The main goal of this study is to achieve the optimal proportions of concrete incorporating GR and MK by maximizing mechanical strengths while minimizing the water absorption (WA) of concrete. To do so, 7 concrete mixtures containing GR are produced with 3 different cement contents: 350, 400, and 450 kg/m3 in conjunction with 2 different water-cement ratios: 0.45 and 0.50. Also, 1 concrete mix is used to optimize the concrete with hybrid blends of GR and MK by employing the response surface methodology (RSM). GR and MK are applied as partial replacements of Portland cement in ranges of 0–30 vol% and 0–20 vol%, respectively. The results show that the use of GR and MK in concrete has a significant effect on its mechanical and durability properties and, thus, reduces the cement consumption which can contribute to decreasing the negative impacts of cement production on the environment. According to the optimization results, 4.2% and 19.5 vol% replacements of cement with GR and MK, respectively, can be considered as the optimum mixture compositions of hybrid concrete to maximize compressive and splitting tensile strengths by about 1–4% and 6–8%, respectively, while minimizing WA by about 48%. Depending on the flexural strength results, the amounts are changed into 1.8% and 14.7% while the flexural strength increases by about 11%.

In order to develop a highly efficient, simple-preparation and renewable explosion suppressant of composite powders, the superfine NaHCO3-shell powder (S-S) composite explosion suppressant was prepared by one-step method with airflow crusher to fulfill the mechanical dry coating of shell powder by NaHCO3, which solved the contradiction between dispersion and suspension force of explosion suppressant particles. The composition optimization and performance test of S-S composite explosion suppressant were carried out with the use of 20 L explosion tank and large tubular coal dust characteristics identification instrument. The results show that when the shell powder particles are coated with NaHCO3, the overall water absorption performance of the powder is reduced, the particle agglomeration phenomenon is weakened, and the dispersion is obviously improved. With the increase of NaHCO3 ratio, the ignition sensitivity of coal dust decreases, and the time to reach the first explosion Pmax is gradually delayed, and both Pmax and (dP/dt)max decrease. With the following explanations: NaHCO3 has a significant effect on reducing (dP/dt)max due to its chemical reaction, while shell powder is beneficial to reducing the Pmax due to its physical barrier effect. The suppression effect of S-S composite explosion suppressant on coal dust explosion is far better than that of pure NaHCO3 or shell powder.

Interlayer is the weakest plane of the entire roller-compacted concrete (RCC) structure and is easily deteriorated under the pressure of water and other environmental factors. Shearing force induced by the different shrinkage in interlayer part is the main reason for that poor performance of the RCC. In this paper, the deformation of RCC concrete and interlayer treatment mortar with supplementary cementitious materials (SCMs, including fly ash and silica fume) and double expansive resources admixtures (HME, containing calcium sulphoaluminate (CSA) and CaO) were studied. Deformation of concrete (produced RCC) and interlayer treatment materials was modeled and compared. Porosity characters of interlayer treatment materials and water absorption of interlayer-treated RCC samples were tested. Results showed that the HME significantly reduced the shrinkage of mortar and the deformation difference degree between layers was shortened. Modified interlayer treatment materials with HME could modify the macroscopic properties of RCC, the low porosity of interlayer and water absorption of interlayer-treated RCC was resulted. The suitable HME content is necessary in interlayer treatment materials and which could improve the performance of RCC.

Recently, natural filler reinforced polymer composites are important materials for various engineering applications. Hence, this present work focuses on utilization of Cocos nucifera shell powder (CNSP) as a filler in vinyl ester (VE) resin to produce particulate composite specimens. The particulate composite plates with various weights or filler contents from 5 to 30 wt% were fabricated, using compression molding technique. The fabricated composites were subjected to tensile, flexural, impact, hardness, heat deflection and swelling behavior tests to obtain their corresponding material properties. Energy dispersive X-ray analysis was carried out on the C. nucifera shell powder/vinyl ester (CNSP/VE) composite specimens to investigate into the presence of their elements, in addition to the aforementioned tests. From the experimental results obtained, it was observed that the optimum mechanical properties of CNSP/VE composites were obtained at 15 wt% of filler content, having tensile, flexural and impact strengths of 38.70, 105.13 MPa and 33.04 kJ/m2, respectively. Also, the heat deflection temperature results varied from 158 (0 wt%, neat VE resin) to 171 °C along various percentages of filler contents. Lastly, the morphological study/analysis of the fractured CNSP/VE composite specimens was conducted by using a scanning electron microscope (SEM) to confirm the experimental data/results obtained. It was evident that CNSP/VE composite structures could be potential substitutes for some synthetic composites. Also, they are suitable for various engineering applications in aerospace, electrical/electronics and automobile industries, based on their properties.

Corin is a type of artificial stone that is produced without the use of cement and is actually a type of polymer concrete. Unsaturated polyester resin is used as an adhesive and aluminum trihydrate ATH powder is used as a filler to produce artificial stone. This stone usually composed of 25 wt% of unsaturated polyester resin and75 wt %of ATH which has low bulk density. Because of this and also other advantages such as non-porous structure result in low water absorption and anti-bacterial properties, Corian artificial stone has many applications. One of the disadvantages of this type of stone is its high price, which is due to the high price of ATH . Another disadvantage of Corinne is its low compressive strength. In this research, in order to reduce the cost price of Corinne and increase the compressive strength, additional materials such as ceramic tile waste powder, stone powder, gypsum and cement have been used. The study was divided into 4 phases. In each phase, one of the additives was substituted forATH by a certain weight. Hardener is a material that is added to the resin as a part of curing. The hardener used in this study is methyl ethyl ketone peroxide of 2 wt % resin. After mixing the resin and hardener, the powder and ATH were added to the mixture and finally, cobalt as catalyst was added to the mixture of 1 wt % resin. After mixing and curing at ambient temperature, compressive strength of samples at1 ,3 ,7 ,14 and 28 days were measured. At each stage, one of these materials replaces part of theATH . Then the compressive strength of the samples at different ages1 , 3 ,7 , 14 and28 were measured. The results showed that by replacing 15% ceramic tile waste, 60% rock powder, 50% gypsum and 50% cement, compared to the weight of , it increased the compressive strength of the samples by20.9 ,16 ,18.6 and 31.2 percent

To obtain the optimum balance between performance and cost, white mud (lime mud) was incorporated into the shell layer of core–shell structured wood-plastic composites (Co-WPCs). The purpose of this study was to observe the effect of the white mud loading in the shell on the water absorption, surface wettability, and mechanical and dynamic thermomechanical properties of Co-WPCs. The results showed that the shell layer improved the water resistance. The flexural strength and modulus increased by filling the shell layer with white mud, but the impact strength decreased. For Co-WPCs with 20% white mud in the shell, the surface free energies of the core layer and shell layer material were similar, which indicated good interfacial adhesion between them. Dynamic thermomechanical analysis indicated that the storage modulus of the Co-WPCs was higher when the white mud content was 15%, and the interfacial interaction parameter B of the composites increased significantly. The storage modulus had the strongest frequency dependence in the glassy state, while the composites displayed no dependence in the rubbery state. The glass transition activation energy of the composites decreased upon increasing the white mud content in the shell layer, indicating that a high white mud content affected the interface of the Co-WPCs. These findings demonstrate that filling the shell with white mud reinforced the Co-WPCs, and 15–20% white mud exhibited the best properties.

Natural fibers are gaining popularity among researchers and academics for use in polymer composites due to their environmental friendliness and long-term viability.A new series of green composites ...

Water absorption is a key property in several tissue paper materials and can be a differentiating factor in terms of consumer choice. The converting modifications applied in the tissue industry can improved absorbency properties. For this purpose, the main goal of the present work is to study the influence of “deco” and “micro” embossing on water absorption capacity, Klemm capillary rise, and liquid spreading kinetics in tissue papers. An industrial never-dried bleached eucalyptus kraft pulp, a creped industrial base tissue paper, and a disintegrated fibrous suspension obtained from the same industrial paper were used to produce structures with and without “deco” and “micro” embossing patterns. The results indicate that the “micro” embossing process promoted bulky and porous structures, enhancing water absorption capacity and Klemm capillary rise properties, while the “dec” embossing pattern decreased water absorption capacity properties. The creping process also increased the water absorption capacity but decreased Klemm capillary rise properties along with the fiber mixtures. Regarding the liquid spreading kinetics, both embossing patterns decreased this property in uncreped isotropic structures, contrary to creped anisotropic structures. The eucalyptus and softwood fibers mixture improved the spreading kinetics compared to the creping process. The performance of structures with and without embossing allowed to quantify the liquid retention properties, combining ISO experimental methods and an optical system that records the liquid interaction with fibrous structures. In conclusion, this laboratory embossing method can be used as an alternative method to optimize converting operations and the final tissue paper characterization, on a laboratory scale.

Environmentally friendly plastics can be degraded biologically in an anaerobic environment. This plastic is synthesized from starch such as sago starch which is available in abundance. In the form of bioplastics, its mechanical properties are still not compared to conventional plastics derived from crude oil, so its application is limited. The incorporation of filler material increases its mechanical properties, one of the selected fillers is hemp fiber as used in this study. Thermoplastic starch from sago with flax fiber as a filler and the addition of Polypropylene to improve mechanical properties with a certain composition to maintain its natural biodegradability. The mechanical properties analyzed were tensile strength, elongation and modulus of elasticity. Water absorption tests were also carried out to observe the water resistance properties. The results of the tensile strength test showed that the best tensile strength value of 9.32 Mpa was obtained at the addition of 35% fiber with a TPS: PP ratio of 1:1.5. The same conditions were obtained for the percent elongation with the results of 10.16% and the modulus of elasticity was 91.73 Mpa. Water absorption showed that 55% filler gave the lowest water absorption, namely 4.41% at a ratio of TPS: PP 1:0.5. The addition of fiber filler into the bio-composite affects the tensile strength, elongation and modulus of elasticity, the higher the volume of filler entering the bio-composite, the lower the value of tensile strength, elongation and modulus of elasticity, or vice versa. The ratio of addition of polypropylene matrix is also influential, the higher the ratio contributes to the tensile strength, elongation and higher modulus of elasticity. High water absorption capacity will reduce the performance of biocomposite, so the lower the water absorption ability, the better the quality of the biocomposite product and the wider its application

To assess several quality parameters of hydraulic concrete, cubic samples of this material are commonly assembled in engineering laboratories using molds. It is ubiquitous the use of cubic metallic molds of volume 125 cm3; these molds require the application of demolding substances (such as oils) on their surfaces to avoid the adhesion of the final hardened concrete sample to the molds. Despite this common practice suitable for evaluating mechanical traits of the materials, the use of a demolding agent spoils the concrete samples for the assessment of surface and water absorption parameters. To overcome this difficulty, we propose a new anti-adherent cubic mold that requires no demolding agent. The construction of the new mold based on anti-adherent polytetrafluoroethene (PTFE, Teflon®) is described with its use. To assess the claimed advantages of the new anti-adherent molds in testing surface and water diffusion traits of concrete samples, experiments on water contact angles, rates of water absorption and drying were performed on concrete specimens obtained with the classic and the new PTFE molds. It was proved the advantage of the anti-adherent mold over common metallic molds. The use of an oil as demolding agent in the concrete samples assembled in metallic molds produced conspicuous differences of water contact angles and absorption in comparison to clean concrete samples produced with PTFE molds.

The natural fine aggregates required for concrete works diminishes day by day with development in the construction industry. Also, the waste rubber obtained from used tires is nonrecyclable, severely impacts the environment and human health, and constitutes a large amount of global waste. In this quest, a systematic, detailed empirical examination has been carried out on the functionally graded rubberized concrete (FGRC) containing rubber fibers as a substitute of fine aggregates to assess the density, compressive strength, flexural strength, split tensile strength, abrasion resistance, water absorption, chloride penetration, and ultrasonic pulse velocity. FGRC was cast in two equal half layers of control concrete and rubber fiber concrete for different replacements (0%, 5%, 10%, 15%, 20%, 25%, and 30%) of rubber fiber and different water–cement ratios (0.35, 0.45, and 0.55). The focus was provided on the combined effect of the w/c ratio and fiber concentration on the FGRC. Microstructural analysis was done on the specimens through scanning electron microscopy and optical microscopy to gain indepth facts about the FGRC interface. Results proved that concrete with a lower w/c ratio proved best in compressive and flexural strength, and there was a decline in the results after the fiber replacement of 20%. Splitting tensile strength also showed less variation after a 20% replacement ratio. Based on the results, the up to 20% of the replacement ratio of waste tire rubber fiber are advised, which can be progressively used at members where desired flexural strength and compressive strength are needed, such as special slabs, bridges, pavements, flyovers, railway sleepers, and other structural members.

Zeolite-based porous ceramics were developed using inexpensive natural zeolite powder with B2O3, Bi2O3, and SiO2 additives and sintered at low temperatures (500–600 °C) compared to those in previous studies (800–1300 °C). The effects of sintering temperature on the porosity, microstructure, flexural strength, thermal conductivity, and water absorption capacity were investigated. As the sintering temperature increased from 500 to 600 °C, the porosity of the zeolite-based porous ceramics decreased from 49.6 to 45.7%, which is attributed to improved densification at high temperature via viscous flow of the glass phase. The flexural strength and thermal conductivity increased from 5.4 to 11.9 MPa and from 0.19 to 0.30 W/mK, respectively, with increasing sintering temperature. The samples sintered at 550 and 600 °C were highly stable in water, with high absorption capacities of 37.6 and 34.1 wt%, respectively. The typical flexural strength, thermal conductivity, and water absorption capacity of the zeolite-based porous ceramic sintered at 550 °C (~ 46% porosity) were 8.4 MPa, 0.24 W/mK, and 37.6%, respectively.

This research aimed to evaluate the effect of adding different polymeric waste percentages and types on the physical, mechanical, thermal and durability properties of soil-cement bricks. Tire and PET (Polyethylene Terephthalate) waste were evaluated at 1.5 and 3.0% percentages. The soil was characterized in terms of shrinkage, compaction, consistency limits, particle size and chemical analyses, whereas the waste particles were submitted to morphological characterization. The bricks were produced in an automatic press with a 90: 10 (m/m) soil: cement ratio. The soil-cement bricks were characterized by density, moisture, water absorption, loss of mass by immersion, compressive strength, thermal conductivity and microstructural analysis. PET waste stood out for its use as reinforcement in soil-cement bricks. The best performance was obtained for bricks reinforced with 1.5% PET, which showed a significant compressive strength improvement, meeting the marketing standards criteria, even after the durability test, as well as obtaining the lowest thermal conductivity values. The percentage increase from 1.5% to 3.0% fostered a significant water absorption and loss of mass increase, as well as a significant compressive strength reduction of the bricks.

The production of ceramic tiles with larger sizes and reduced thickness has increased the challenge of producing high-quality ceramic tiles in short single-firing cycles. For porcelain tiles, the pressing step is of upmost importance for the microstructure of the green bodies. The particle size distribution, mineral composition of the pastes and porosity before firing define the water flow during the decoration process. Hydro deformation is the curvature of unfired ceramic tiles caused by water absorption during the decoration step before firing. In this work, the hydro deformation is studied in function of tile thickness, compaction, and clay composition according to a 2K factorial design. Two compositions of porcelain tiles (glazed and polished) were pressed at two thicknesses (3–6 mm) and pressing pressures (35.5–49.8 MPa) forming ceramic tiles with 55 × 110 mm² of surface area. Chemical (XRF), mineralogical (XRD), thermogravimetric (TG), specific surface area (BET), granulometric, bulk density, and porosity analyses were performed for the green tiles of both compositions. To simulate the hydro deformation during the decoration step, the curvature (mm) of the tiles was studied within a 0–180 min interval. The water absorption rate through the surface (g.m−2·s−1) of the tiles in an interval of 0–180 s was studied as a function of thickness, pressure and porcelain tile composition. As a result, the thickness of the tiles can change the curvatures from concave to convex. Pressing conditions and composition of the tiles can change the water absorption rates. Porcelain tiles with higher content of clay minerals develop convex curvatures. For tiles with lower content of clay minerals, concave curvatures were developed.

Date palm fibre is considered as an agricultural waste suitable as reinforcement for polymeric composites has received interest as an interior component in the automotive industry. The aim of this work to investigate the physical and mechanical properties of date palm fibre (leaf stalk, tree trunk, fruit stalk and leaf sheath) reinforced epoxy composites and date palm/bamboo hybrid composites suitable for non-structural and semi-structural applications. The different composites were fabricated using a hand lay-up technique in combination with compression moulding method. Date palm fibre/bamboo hybrid composite, and pure composites were characterized by various mechanical testing such as tensile, flexural and low-velocity impact testing. Exposure to liquid water and environmental conditions affect the durability of biobased composites. The water absorption behaviour and its effects on the thickness swelling, changes in density and physical performance of different composites were further investigated. The experimental results of the date palm fibre/bamboo hybrid composite exhibited the highest mechanical properties compared to date palm fibre composite without hybridisation. The tensile strength, flexural strength and impact toughness values for the date palm/bamboo hybrid composite were recorded at 39.16 MPa, 61.10 MPa and 12.70 J/m, respectively. Interestingly, the physical test of thickness swelling and water absorption results has indicated that date palm fibre/bamboo hybrid composite displayed 27.68% and 15.39% less when compared with single date palm fibre composite. Therefore, the results have discovered that the date palm fibre/bamboo hybrid composite has the prospective to be applied as a non-structural and semi-structural components.

Static bending strength and dimensional stability of epoxy composite is an important property for most of the structural applications. Types of filler used with addition of tetraethoxysilane (TEOS) in the epoxy system might improve the properties of the composite. In this research paper, two types of epoxy composites were prepared: the first batch involved epoxy resin mixed with three different fillers; nanocellulose, tannin, and activated carbon at three different doses; 5%, 10% and 15%, while the second batch was a reactive modification using 1%, 2% and 3% doses of (TEOS) as cross-linker agents at 10% dose of each filler. The dimensional stability and static bending properties of epoxy mixed with commercial nanocellulose, tannin, and laboratory-made activated carbon as fillers were investigated. We found that the nanocellulose, tannin, and activated carbon acted as hydrophobic buffer to slow the water absorption at the 10% dose. The thickness swelling was also significantly lower (P

Neem fibers are traditionally added as reinforcements in adobes. Laboratory experiments including, compressive strength, three-point bending strength, water absorption, erosion and thermal conductivity were carried out on adobes made with soil and reinforced with two neem fibers types (straw and leaves) at 0, 1, 2, 3 and 4%. It has been found that mechanical, thermal, and durability properties of adobes were globally improved. Furthermore, leaves neem fibers contribute strongly in comfort thermal, but their use has a negative effect on durability. Nevertheless, adobes reinforced with neem fibers are suitable as building materials with substantial thermal comfort and environmental benefits.

By hybridizing fibers, natural fibers are widely employed to substitute synthetic fibers in all feasible applications. The present study focuses on the development and characterization of hybrid Ar...

The natural fiber composites are emerging as replacement materials in wide engineering fields. In this work, banana, sisal, and banana-sisal fibers of three different fiber lengths namely 3 mm, 5 m...

The importance of adding surface treated Ramie fibre and nanoclay in epoxy resin composites was investigated in this research. The key goal of this study was to demonstrate the significance of surface treatment on naturally occurring fibres and fillers as they are indented for use in high-performance composites. The surface of the Ramie fibre was treated using an amino silane whereas the nanoclay was organo-montmorillonite (OMMT). The composites were made using a hand layup process of 40 vol% Ramie fibre and 0.5, 1.0, 1.5, 2.0, and 2.5.% nanoclay reinforcement. The specimens are then tested for various mechanical properties such as tensile, flexural, impact, and hardness in accordance with ASTM standards in order to determine the composite’s strength. Wear and fatigue properties were also investigated to determine the outcome of surface-treated fibre and particle in a polymer matrix. The mechanical properties of the 40 vol% Ramie fibre and 1.5 vol% OMMT nanoclay are found to be better. Wear tests showed that a composite containing 40vol. % of fibre and 1.5vol.% of OMMT nanoclay produced high abrasion resistance. Similarly, fatigue life counts of composites containing 1.0vol. % nanoclay shows 44,218 cycles. Water absorption resistance is balanced because of silane-treated ramie fibre and OMMT nanoclay in epoxy composite. There is no vast decrement in hydrophobicity on compare with bare resin. The SEM images show exfoliation of OMMT nanoclay in the matrix as well as increased Ramie fibre adhesion to the matrix.

Poly(butylene succinate) (PBS)/soy protein isolate (SPI) bio-composites were reactive compatibilized by adding dibenzoyl peroxide (BPO) and hexanediol diacrylate (HDDA) via melt blending in an internal mixer. The structure and properties of composites were studied by scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic mechanical analyses, rheological tests, contact angle measurements, thermogravimetric analyses, differential scanning calorimetry, wide-angle X-ray diffraction, tensile tests and water absorption tests. The results showed that a branched graft copolymer (SPI-g-HDDA-g-PBS) was produced with the aid of BPO and HDDA via melt blending, which served as a compatibilizer. It improved the compatibility and enhanced the adhesion between PBS matrix and SPI phase by forming a network structure in the composites. The grafts contents in the composites were determined by Soxhlet extraction. The crystal structure of PBS was not changed in the composites. The melt viscosity and elasticity, hydrophobicity, thermal stability and crystallinity of PBS/SPI-HDDA/BPO composites were improved. The tensile strength and Young’s modulus increased 46% and 55%, while the water absorption decreased ~ 20% for PBS/SPI-HDDA/SPI (80/20/0.1) composite in comparison with PBS/SPI (80/20) composite. The potential usage of the bio-composites is household and industrial products and disposable packaging and items.

he use of CFRP composites is significantly increasing in the aerospace, automotive, and marine industries, particularly in safety critical primary structures. This work presents a newly developed experimental approach to investigate the directional diffusion of water in CFRP composites with the use of Fick's law. The approach is used to study the effect of fiber architecture on directional diffusion rates, with a particular focus on the role of fiber waviness in the diffusion process. A comparison of water diffusion is made in three different fiber architectures: Unidirectional (UD), plain weave, and twill weave. The specimens were fully immersed in 90°C purified water until their maximum moisture saturation was achieved, with some specimens being selectively exposed from the edges only to obtain the directional diffusion coefficients. The water penetration process into the CFRP structure initiate from the micro-cracks and defects. The experimental work of this study shows sharp mass increases within the first stage followed by an equilibrium stage where saturation is present. The interfacial region is found to be a critical parameter where detachment of the interfacial fiber/matrix bonding is observed further demonstrating the potential effect of different fiber architecture in this region. UD fiber architecture showed ~20% higher diffusion coefficient in the Dx,y direction compared with plain and twill woven architectures. The weave patterns in 2D woven fiber architectures are therefore believed to play a key role on the moisture ingress mechanism and subsequently contributed in slowing down the capillary process in the interfacial region. This has implications for materials development and selection for CFRP composites used in moist environments.

Carbon fiber reinforced plastics (CFRP) with the matrix of thermoplastic resin called as carbon fiber reinforced thermoplastics (CFRTPs) has been widely used in the industrial fields. Recently, a thermoplastic epoxy resin (TP-EP resin) has been developed as the matrix of CFRTP and carbon fiber reinforced TP-EP strands (CF/TP strands) molded by pultrusion method began to be used as tension rods for infrastructure under water absorption. On the other hand, an accelerated testing methodology (ATM) for predicting statistically long-term creep and fatigue strengths of CFRP was established by the authors. This study examines the prediction of statistical life time for these developed CF/TP strands at creep and fatigue tension loadings under the wet condition of water absorption with comparison to similar prediction under a dry condition by using our developed ATM. First, the static, creep, and fatigue tensile strengths of CF/TP strands were measured statistically at various constant temperatures under wet and dry conditions. The statistical long-term creep and fatigue tensile strengths for CF/TP strands under wet and dry conditions are predicted by substituting the measured data into the formulations of these strengths on our developed ATM. Finally, the influences of water absorption on the statistical long-term creep and fatigue strengths of CF/TP strands are cleared. In particular, the degradation of relaxation modulus of matrix TP-EP resin with increasing of elapsed time is accelerated with the water absorption, and the degradation of creep strength of CF/TP strand with increasing of elapsed time is also accelerated with the water absorption in the similar manner of matrix resin. On the other hand, the fatigue strength of CF/TP strand decreases scarcely with water absorption although this fatigue strength depends remarkably on the number of cycles to failure.

This work aims to investigate the effect of chitosan powders on the mechanical, morphological and thermal behaviour of nitrile rubber (NBR). The chitosan content has been varied between 0 and 15 ph...

Enormous amounts of plastic wastes are generated worldwide and the approaches related to plastic recycling or reusing have become the research focus in the field of composite materials. In this study, green composites were prepared via melt-blending method using high-density polyethylene (HDPE) sourced from plastic bags as a matrix and sugarcane bagasse (SCB) fiber as reinforcing filler. The effects of fiber loading (5, 10 and 15 wt%) and fiber modification on the mechanical and dimensional stability (weight gain by water absorption) properties of the green composites were investigated. Results showed that the inclusion of SCB fiber into recycled HDPE matrix increased the composite stiffness but decreased the mechanical strength and resistance to water absorption. With the fiber modification through alkali treatment, the mechanical strength was remarkably improved, and the modulus and water absorption of the composites were found to be reduced. From the finding, it can be concluded that the prepared green composites free of coupling agent could add value to the plastic and agricultural wastes, and serve a potential candidate to replace some conventional petroleum-based composites.

Water is a crucial element in the concrete mix and is alone responsible for concrete work ability and cement hydration. The massive quantity of potable water consumed during the production of concrete is a concern. In general, fresh and hard concrete qualities are most influenced by the quantity and water quality. The use of magnetic water in concrete gives many benefits when it comes to increasing its properties. A substantial quantity of water can be saved by substituting potable water with magnetized water in concrete. In this study, the effects of magnetized water on the concrete's mechanical and durability properties were tested. Four different combinations were made using potable water and magnetic water. Mechanical properties including compression, flexural, tensile strength, and SEM analysis were evaluated. Water absorption, acid resistance, and corrosion resistance were all tested as part of the durability tests. According to the results of the experiments, employing magnetic water for concrete preparation and curing enhanced the mechanical properties and durability. Concrete mix MMMC prepared and subjected to curing using magnetized water has a 14.86% greater compressive strength than ordinary concrete. Similarly, tensile and flexural strength of mix MMMC amplified to 14.32% and 14.02%, respectively. Besides, the consumption of chemical admixtures also considerably reduced in magnetized water imbibed concrete.

Bio-composites were produced from untreated (UT) and hydro-thermally treated (HTT) wheat straw (WS) particles and wood, and their dimensional stability and mechanical properties were investigated. The HTT treatment consisted of subjecting the WS particles to a steam explosion process for 8 min at 180 °C. The HTT and UT WS particles were mixed with the wood particles at 10, 20, 30, and 40% ratios. The physical properties, including density, water absorption (WA), and thickness swelling (TS), were determined for the bio-based composites. The mechanical properties evaluated included the modulus of rupture, modulus of elasticity, and internal bond strength. Statistical analyses showed that the hydro-thermal treatment and the WS ratio had significant effects on the dimensional stability and mechanical properties of the bio-composites. The WA of the composites after 2-h and 24-h rose significantly when the HTT WS particle ratio was increased from 10 to 40%. The 2-h and 24-h WA values of HTT-10 were 6.3% and 5.3% lower than those of UT-10, respectively. Improvements in the 2-h TS value were achieved by the HTT WS particles at the 10% ratio, and in the 24-h TS value at the 10 and 40% ratios. The mechanical properties of the composites were higher in the HTT group, but decreased in both the UT and HTT groups as the WS ratio increased.