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Biobased superabsorbent is considered as an interesting polymeric material with excellent water absorption capacity. It can act as an active agent carrier and soil conditioner along ...with others. Howsoever, extensive usage of polymeric superabsorbent derived from conventional petroleum sources is posing serious threats to sustainability of the ecosystem. In this facet, a high biobased content (63 %) superabsorbent was synthesized using starch and itaconic acid as renewable resources. The prepared superabsorbent polymer was authenticated by its high-water absorption capacity (650 g/g) due to the presence of porous morphology as supported by SEM image analysis and the presence of various polar groups in its structure as confirmed by Fourier transform infrared (FTIR) spectral analysis. The superabsorbent hydrogels with different compositions were prepared and their performance was evaluated towards water absorption with and without load, and in salt solutions. The swelling kinetic studies of the hydrogels revealed faster water absorption with higher itaconic acid content. The urea encapsulated hydrogels were used in soil to judge their abilities for water holding capacity, seed germination rate, soil porosity enhancement, etc. Moreover, the hydrogels possess good biodegradability as confirmed by the soil burial study, and thereby endowing the environmentally benign characteristic which can overcome the shortcomings of petroleum-based hydrogels. Thus, they have great potential to be used in agricultural applications, especially as environmentally friendly superabsorbent.
Studies were carried out to find a relation between the important physical property, i.e., water absorption and the main mechanical parameter, i.e., compressive strength (
), of concretes containing ...coal fly ash (CFA) in the amounts of 0% (CFA-00), 20% (CFA-20%), and 30% (CFA-30). The methodology of the water absorption tests reflected the conditions prevailing in the case of reinforced concrete structures operating below the water table. The microstructure of all materials was also assessed. Based on the conducted studies, it was found that both the
of concretes with the addition of CFA and its water absorption depended on the percentage of waste used, whereas both analyzed parameters were closely related to the structure of the cement matrix and interfacial transition zone area between the coarse aggregates and the paste. It should be stated that at the content of 20% CFA in the binder composition, an increase in the
of the material is observed, with a simultaneous increase in its water absorption. On the other hand, the addition of 30% CFA results in a significant decrease in both the strength of the composite and its water absorption. Thus, it was found that in the case of concretes with the addition of CFA, the strength of the material is directly proportional to the level of its water absorption. Moreover, the concrete including 30% CFA may increase the durability of reinforced concrete structures subjected to immersion conditions. From an application point of view, the obtained research results may be helpful in understanding the impact of the CFA additive on the level of water absorption in cement concretes with this waste.
The volume shrinkage of polymethyl methacrylate (PMMA) bone cement has been solved by the expandable additives. However, the water absorption and swelling capacity of composite were not maximized as ...the rapid solidification of the cement and the poor connectivity of the additives in the matrix. In this study, the double‐bridged structure was constructed in PMMA‐based bone cement. Poly(methyl methacrylate‐acrylic acid)‐graphene oxide P(MMA‐AA)‐GO was synthesized by the dispersion polymerization, graphene oxide (GO) with sheet layer formed a bridging effect between the poly(methyl methacrylate‐acrylic acid) P(MMA‐AA), accelerating water absorption; hydroxyethyl methacrylate in the liquid formed capillary networks, which bridged all the expansion units, increasing the pathways of water transfer in the matrix. The double‐bridged structure in the composite synergistically accelerated water absorption and swelling, causing complete water absorption and swelling performance before solidification, with maximum water absorption and swelling ratios of 125.2 ± 3.2% and 115.2 ± 4.7%, respectively. Surprisingly, the compressive strength of the composite had also been improved, and the maximum value was 78.3 ± 3.2 MPa, which satisfied the minimum compressive strength of acrylic implants in ISO 5833‐2002 and ASTM F451‐2016. This biomaterial exhibited a promising application prospect as its excellent expansion capacity and mechanical properties.
The double‐bridged structure consisting of P(MMA‐AA)‐GO and P(MMA‐HEMA) in the composite bone cement synergistically accelerated water absorption and swelling, causing complete water absorption and swelling behavior before solidification of the matrix, with maximum water absorption and swelling ratios of 125.2 ± 3.2 % and 115.2 ± 4.7 %, respectively.
This study aimed to evaluate the thermocycling effect on the retentive force of 3 different retentive inserts in 3 denture attachments (Blue, Pink, Clear retentive inserts in LOCATOR; Blue, Pink, ...Clear retentive inserts in LOCATOR R-Tx; and White, Yellow, Green retentive inserts in Novaloc) (n=10). Maximum retentive force of each retentive insert was evaluated at baseline, 7-day water storage, and after 5,000-, and 10,000- cycle thermocycling. The water absorption percentage of the retentive inserts was also determined. Comparing between baseline and 7-day water storage, the retentive forces of the LOCATOR and LOCATOR R-Tx groups were significantly reduced (p<0.05), while the retentive force of the Novaloc group was significantly increased (p<0.05). Comparing between 7-day water storage and 10,000-cycle thermocycling, the retentive force of most retentive inserts remained unchanged (p>0.05). The water absorption percentage of the LOCATOR and LOCATOR R-Tx groups was significantly greater than that of the Novaloc group (p<0.05).
The investigation of durable and sustainable construction materials has encouraged significant advancements in concrete technology, one such notable innovation is integration of microbial processes. ...This paper focuses on the realm of microbial concrete, examining material characterization, crack healing mechanism, sustainability and economic evaluation. Material characterization by techniques including SEM, XRD and TGA, providing important insights into microstructures and composition of bacterial concrete, providing a deeper understanding of its properties and potential applications. Self-healing mechanisms enabled by bacterial spores embedded in concrete, present promising solutions to reduce deterioration of concrete. These mechanisms triggered by exposure to moisture, initiates the process of ureolysis, leading to the formation of calcium carbonate and the sealing of cracks. Despite the initial higher cost associated with microbial concrete, its long term benefits, including extended lifespan and reduced maintenance costs, justify further research and investment. There is a need for interdisciplinary collaborations, long term performance studies under different environmental conditions and the development of improved healing agents are recommended for future research. Microbial concrete holds potential to transform the construction sector, leading to the path towards durable and sustainable concrete structures.
•Carbonation and curing can significantly enhance its microstructure.•Microbial concrete offers long-term savings in maintenance.•Enhanced durability and strength of MICP.•Environmental and economic sustainability of MICP.•Advancements in microbial concrete technology drive its effectiveness.
In recent years, basalt fiber reinforced polymer composites have gained popularity as an alternative to synthetic glass fiber reinforced polymer composites. Unidirectional 0°/90° basalt ...fiber-reinforced SiC micro and nano filled composites were tested for tensile, flexural, impact and hardness characteristics to determine the optimal composition. Comparing the mechanical properties of the composites reinforced various combinations of SiC micro or nano filler particles 4 wt% nano SiC filler addition exhibits superior properties. The scanning electron microscopy (SEM) images also reveals the improved interfacial interaction between the fiber mat and matrix for filler concentration up to 4 wt% SiC nanoparticles. Moreover, the wear resistance of the composites with 4 wt% SiC micro particles was better with low weight loss in wear test. The water absorption ability of the composite was low for the composites reinforced with 2 wt% SiC nanoparticles. Most of the properties of the composition with optimum filler addition are good enough for structural applications.
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•Water absorption of FRP included a Fick's diffusion and deterioration responses.•Linear relationship between mechanical properties and bonding water was established.•Mechanical properties decreased ...owing to resin plasticization and interface debonding.•Long-term life prediction was conducted to provide an application guideline of FRP.
The hygrothermal aging of fiber reinforced polymer (FRP) composite rod served as bridge cables played a key role on the long-term service performances. In the present paper, two types of pultruded carbon/glass fiber reinforced epoxy hybrid composite rods, one with uniformly dispersed carbon and glass fibers, and the other with glass fiber shell and carbon fiber core, were investigated on the water uptake and interface shear strength. The aging condition was immersion in deionized water at 40 °C, 60 °C and 80 °C. Interface shear strength degradation mechanism was revealed by thermal analysis and microstructure analysis. It was found that the water absorption of two types of hybrid rods represented the two-stage behavior. For the rod of uniform fiber dispersion, more water uptake in the second stage occurred compared to that of the shell/core rod, which was attributed to the resin rich area and interface debonding of fiber/resin. Long-term hygrothermal exposure led to a remarkable degradation in the interfacial shear strength of the rods, up to 17.5% ∼ 42.1%. The resin plasticization and interface debonding were the main factors contributed to the strength degradation. Based on the Arrhenius equation, the long-term life prediction of the interfacial shear strength under two typical bridge service environments was conducted to the design guideline of hybrid rods in the bridge engineering.
This paper presents a literature review and experimental results on the effect of high incorporation levels of fly ash (FA) and recycled concrete aggregates (RCA), individually and jointly, on the ...pore system of concrete that remarkably influences its durability. For that purpose, apart from an extensive literature review, three tests were performed, including electrical resistivity (ER) test, which indirectly measures the interconnected porosity of concrete, and water absorption (WA) by capillarity and immersion tests that both depend on the pores number and size but in a different way. A comparison between the experimental results and the literature is also presented to show the main findings and the research needs. The results show that WA increases and ER decreases with increasing incorporation level of RCA, and the opposite occurs with the addition of FA for both tests. The reduction percentage of WA was higher in mixes with both RCA and FA when compared to the sum of reductions in mixes with only RCA or FA. Thus, it is advisable to produce concrete with both mentioned non-traditional materials in terms of WA and ER of concrete. In addition, the benefit of incorporating of FA and RCA in concrete increased even more when superplasticizers was used.
•The influence of curing conditions on the sorptivity, electric flux and carbonation depth were investigated.•Longer curing time, higher humidity and appropriate temperature was helpful to improve ...the impermeability of concrete.•The relationship between water absorption and other permeability was discussed.
The influence of mineral admixtures and curing conditions on the permeability of concrete with high volume mineral admixtures is investigated. Fly ash and ground granulated blast furnace slag (GGBFS) are used to replace 50% cement, the water absorption, capillary water absorption, sorptivity coefficient, electric flux and carbonation depth of concrete with mineral admixtures are tested under different curing conditions, such as the curing time, curing humidity and curing temperature. The test results show that the water absorption, capillary water absorption, sorptivity coefficient, electric flux and carbonation depth of concrete decrease with the longer standard curing time, higher curing humidity and appropriate curing temperature, and decrease with the increasing of GGBFS content. It is also shown that the permeability of concrete with high volume mineral admixtures is very sensitive to the curing conditions.
The use of waste brick powder (WBP) as supplementary cementitious material (SCM) provides an effective approach to reclaiming construction and demolition (C&D) waste. This research shows the ...evolution of preparing eco-friendly mortar with various fineness levels and replacement ratios of WBP from waste brick in C&D waste. Due to the pozzolanic activity and filler effect of WBP, incorporating an appropriate content and fineness of WBP refines the pore network of cementitious materials, while the number of hydration products decreases with WBP addition. With WBP incorporation, the water demand increases and mixture slump decreases, while the use of WBP improves the drying shrinkage resistance. The pozzolanic activity increases with increasing WBP fineness; when the WBP fineness is higher than the cement fineness, the compression strength with WBP contents up to 15% is superior to that without WBP, while the compression strength decreases with WBP incorporation when the WBP fineness is close to or lower than the cement fineness. Incorporating an appropriate WBP content decreases the water absorption of mortar, and the water absorption further decreases with increasing WBP fineness; for example, when the median diameter of WBP is 6 μm and 42 μm, the capillary absorption coefficient of mortar with 30% WBP is 34.1% lower and 10.3% higher than that of plain mortar, respectively. In addition, a similar conclusion is observed for the water distribution in WBP mortar.
