Water Absorption Characteristics Research Articles

Investigation on the Tea Polyphenol/Swelling Gels to Inhibit Coal Spontaneous Combustion: An Experimental Study

ABSTRACT Developing new fire-fighting material is most significant for effective prevention and control of coal spontaneous combustion. To enhance the flame-retardant performance of the gel, the tea polyphenol/swelling gels are developed using a water-soluble polymerization method. Thermogravimetric analysis, programmed temperature experiments, and Fourier-transform infrared spectroscopy are used to reveal the structural characteristics, microscopic morphology, and thermal stability of the gel. Experimental testing the tea polyphenol/swelling gels’ water absorption, water retention, and reusability as well as their inhibitory effect on coal spontaneous combustion. The results showed that the prepared tea polyphenol/swelling gels exhibited a porous three-dimensional network structure, with a maximum swelling ratio of 607.2 g/g and a salt absorption rate of 121.4 g/g. After the testing coal sample is treating by the tea polyphenol/swelling gels, its CO production rate is sharply decreased, but the corresponding ignition point temperature and flame-retardant rate are significantly increased. The activation energy in the first stage is increased by 32.2 kJ·mol−1, in the second stage by 4.0 kJ·mol−1, and in the third stage by 23.2 kJ·mol−1. Additionally, the active functional groups such as hydroxyl and methyl in the coal are also reduced by the treatment of tea polyphenol/swelling gels. Correlation analysis indicate that the inhibition effect of coal spontaneous combustion can be achieved by reducing -OH, CH3/CH2 groups, while the increasing of C = C, C- O, C- H functional groups in the coal. Moreover, the tea polyphenol/swelling gels performing the characteristics of excellent water absorption, inhibiting coal spontaneous combustion by absorbing heat, covering the coal microstructure, and inhibiting the oxidative activity of coal molecules. This study can provide theoretical guidance for the application of swelling gels in inhibiting coal spontaneous combustion.

Effect of Electric Field on Water Absorption and Permeability Characteristics of Silicone Rubber

Effect of Electric Field on Water Absorption and Permeability Characteristics of Silicone Rubber

The Effect of Sodium Tripolyphosphate and Guar Gum on Physical Characteristics of Analog Rice from Gaplek Flour

Gaplek flour is a processed product of cassava preservation abundant during the harvest season in Lampung Province. The high carbohydrate content in cassava facilitates the processing of gaplek flour into carbohydraterich food source, such as analog rice. Therefore, this study aimed to investigate the effect of adding STPP and guar gum on the formulation of analog rice made from 70% gaplek flour and 30% corn flour. Analog rice was produced using the extrusion method with a twin-screw extruder. The results showed that the addition of STPP did not affect water absorption characteristics. The solubility of rice in deep water also decreased with increasing amounts of STPP and guar gum. Meanwhile, guar gum significantly increased water absorption and reduced the solubility of rice in water. The degree of gelatinization decreased with the addition of both materials. The addition of 0.3-0.5% STPP and 0.5-2% guar gum had no significant effect on hardness, stickiness, elasticity, and cohesiveness of analog rice prepared using a cooker.

Vanadium and strontium co-doped hydroxyapatite enriched polycaprolactone matrices for effective bone tissue engineering: A synergistic approach

Scientific research targeted at enhancing scaffold qualities has increased significantly during the last few decades. This emphasis frequently centres on adding different functions to scaffolds in order to increase their usefulness as instruments in the field of regenerative medicine. This study aims to investigate the efficacy of a multifunctional sustainable polymer scaffold, specifically Polycaprolactone (PCL) embedded with hydroxyapatite co-doped with vanadium and strontium (HVS), for bone tissue engineering applications. Polycaprolactone was used to fabricate the scaffold, while hydroxyapatite co-doped with vanadium and strontium (HVS) served as the nanofiller. A thorough investigation of the physicochemical and biological characteristics of the HVS nanofiller was carried out using cutting-edge techniques including Dynamic Light Scattering (DLS), and X-ray Photoelectron Spectroscopy (XPS) and in vitro cell studies. A cell viability rate of more than 70 % demonstrated that the synthesised nanofiller was cytotoxic, but in an acceptable range. The mechanical, biological, and physicochemical properties of the scaffold were extensively evaluated after the nanofiller was integrated. The water absorption characteristics of scaffold were enhanced by the addition of HVS nanofillers, leading to increased swelling, porosity, and hydrophilicity. These improvements speed up the flow of nutrients and the infiltration of cells into the scaffold. The scaffold has been shown to have important properties that stimulate bone cell activity, including better biodegradability and improved mechanical strength, which increased from 5.30 ± 0.37 to 10.58 ± 0.42 MPa. Further, its considerable antimicrobial qualities, blood-compatible nature, and capacity to promote biomineralization strengthen its appropriateness for usage in biomedical applications. Mainly, enhanced Alkaline phosphatase (ALP) activity, Alizarin Red Staining (ARS) activity, and excellent cell adhesive properties, indicating the outstanding osteogenic potential observed in rat bone marrow-derived stromal cells (rBMSC). These combined attributes highlight the pivotal role of these nanocomposite scaffolds in the field of bone tissue engineering.

Preparation and Properties of Attapulgite-Hydroxyethyl Cellulose Composite Poly (Acrylic Acid-co-2-acrylamide-2-methylpropanesulfonic Acid) Concrete Internal Curing Material

Attapulgite-hydroxyethyl cellulose-poly (acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid) (ATP-HEC-P(AA-co-AMPS)) in-concrete curing material was synthesized by aqueous solution polymerization using attapulgite (ATP) as an inorganic filler and hydroxyethyl cellulose (HEC) as a backbone. The effects of relevant factors such as ATP dosage, HEC dosage, degree of neutralization, initiator quality, and cross-linking agent quality on the water absorption characteristics of ATP-HEC-P (AA-co-AMPS) were investigated through expansion tests. The micro-morphology of ATP-HEC-P (AA-co-AMPS) was also comprehensively characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, a thermal analysis, and other applicable means. The results showed that the prepared ATP-HEC-P (AA-co-AMPS) had a strong water absorption and water retention capacity, with a water absorption multiplicity of 382 g/g in deionized water and 21.55% water retention capacity after being placed at room temperature for 7 d in a bare environment. Additionally, ATP-HEC-P (AA-co-AMPS) showed good performance for absorbing liquids within the pH range of 7–12. The material’s thermal stability and mechanical properties were also significantly improved after the addition of ATP. The preparation cost is low, the process is simple, and the material meets the requirements for concrete curing materials.

Bioinspired Photoelectronic Synergy Coating with Antifogging and Antibacterial Properties.

Optically transparent glass with antifogging and antibacterial properties is in high demand for endoscopes, goggles, and medical display equipment. However, many of the previously reported coatings have limitations in terms of long-term antifogging and efficient antibacterial properties, environmental friendliness, and versatility. In this study, inspired by catfish and sphagnum moss, a novel photoelectronic synergy antifogging and antibacterial coating was prepared by cross-linking polyethylenimine-modified titanium dioxide (PEI-TiO2), polyvinylpyrrolidone (PVP), and poly(acrylic acid) (PAA). The as-prepared coating could remain fog-free under hot steam for more than 40 min. The experimental results indicate that the long-term antifogging properties are due to the water absorption and spreading characteristics. Moreover, the organic-inorganic hybrid of PEI and TiO2 was first applied to enhance the antibacterial performance. The Staphylococcus aureus and the Escherichia coli growth inhibition rates of the as-prepared coating reached 97 and 96% respectively. A photoelectronic synergy antifogging and antibacterial mechanism based on the positive electrical and photocatalytic properties of PEI-TiO2 was proposed. This investigation provides insight into designing multifunctional bioinspired surface materials to realize antifogging and antibacterial that can be applied to medicine and daily lives.

Effects of moisture absorption analysis of kevlar/carbon/glass/polyurethane epoxy hybrid sandwich composites with nano silicon particles

ABSTRACT Hybrid sandwich polymer composites are widely used in aviation applications due to their attractive properties, such as their excellent strength capability, high modulus values, excellent stiffness properties, and greater wear resistance. This study aims to analyse the mechanical properties of degraded hybrid sandwich specimens exposed to moisture and investigate the moisture behaviour of the degraded sandwich panels. These panels are reinforced with woven fabrics made of kevlar, carbon, and glass fibres. The hand layup technique was employed to create the structures. The hybrid sandwich composite samples are submerged in normal seawater at ambient temperature for varied duration’s to measure the fibres’ water absorption characteristics. The study investigated the mechanical characteristics of an ageing moisture hybrid sample during tensile, flexural, and compressive tests. Novel stacking sequence arrangements (01 K/01 C/01 G/PUR/01 G/01 C/01 K) were used to enhance the stiffness, load-carrying capacity, yield strength, and other mechanical characteristics of the sandwich structures. The degraded sandwich panels demonstrated that water absorption significantly influences the tensile, flexural, and compressive properties of degraded sandwich structures compared with the results of regular sandwich panels. The tensile (31.67%, 40.40%, and 47.089%), flexural (63.13%, 66.05%, and 70.14%), compressive (33.14%, 39.37%, and 38.40%), and water absorption (3.75%, 3.97%, and 4.71%) test results were analysed.

Biodegradability and Water Absorption of Macadamia Nutshell Powder-Reinforced Poly(lactic Acid) Biocomposites

This study investigates the biodegradability and water absorption properties of Macadamia nutshell powder and poly(lactic acid) (PLA) biocomposites using a Design of Experiments (DOE) approach. The influences of processing methods, the Macadamia nutshell powder’s weight content, and the powder’s condition are studied. A biodegradability test is performed in accordance with the American Society for Testing and Materials (ASTM) D5338-11 by burying the test specimens in wet garden soil at a controlled temperature of 50 °C and 100% humidity. The specimens obtained by counter-rotating processing exhibit varying weight loss patterns with an increasing powder weight content, while the specimens obtained by co-rotating processing demonstrate consistent behaviour. This study highlights the complex nature of PLA biodegradation, which is affected by diverse factors such as test conditions and environments, thereby contributing to a deeper understanding of the sustainability implications. A water absorption test is carried out in accordance with ASTM D570-98. It is shown that the water absorption characteristics are predominantly determined by the hydrophilic nature of Macadamia nutshells, with an increased powder weight content leading to higher absorption. Pure PLA, due to its hydrophobic nature, exhibits minimal water absorption. By unravelling the complexities of PLA biodegradation and water absorption in Macadamia nutshell and PLA biocomposites, this study not only advances the understanding of materials’ behaviour but also underscores the potential sustainability implications of utilizing natural resources in composite materials. This research contributes valuable insights to the broader discourse on environmentally friendly materials and their role in promoting sustainable practices.

EXPLORING THE POTENTIAL OF RED ASH AND MARBLE CHIPS AS ALTERNATIVES IN BASE COURSE MATERIAL VIA BLENDING WITH CRUSHED STONE AGGREGATE

Despite its abundance, red ash has compaction issues owing to its lightweight, rough circular surface, and high porosity. The usage of conventional base course materials across the country incurs shipping expenses and takes time, slowing down projects because they are only widely available in limited areas across the country. In this study, non-probably sampling approach was used to examine the potential for employing red ash and marble chips as an alternative base course material by mixing them with crushed stone aggregate (CSA). In order to accomplish the goal of this study, an experimental test was conducted via trial and error, focusing on the mechanical stabilization of red ash and marble chips. Their physical characteristics were subsequently assessed through laboratory testing. In the laboratory, nine (9) samples of red ash and marble chips blended with CSA in varying percentages (0, 5, 10, 15, 20, 25, and 30 percent) were examined. The laboratory test results showed that 100% red ash and marble chips gave; CBR, SG, AIV, ACV, LAA, FI, EI, water absorption, and soundness: 55.4%, 2.38%, 18.20%, 26.34%, 19.69%, 5.59%, 12.09%, 2.5% and 13.80 and 83.6%, 2.63%, 19.70%, 26.41%, 19.75%, 23.2%, 16.9%, 1.24% and 12.22 respectively. Several of these test results align with the Ethiopian Road Authority (ERA) standard specifications; however, the findings from the CBR, water absorption, and soundness tests do not. Thus, mechanical stabilization was employed to improve the samples' physical characteristics. Experimental results are obtained by mixing 20% red ash, 20% marble chips, and 60% CSA. The values for CBR, SG, AIV, ACV, LAA, FI, EI, water absorption, and soundness are 102.5%, 2.55, 14.23%, 19.84%, 7.92%, 18.61%, 20.77%, 0.83%, and 7.38, respectively. The CBR, water absorption, and soundness characteristics all meet the necessary ERA standard specifications for crushed weathered rock (GB2) and natural coarsely graded granular materials (GB3) at this particular proportion. Hence, it is recommended to incorporate red ash up to 20% and marble chips up to 20% by weight, alongside 60% CSA, for constructing road base courses, particularly when these materials are reasonably accessible from construction sites and are widely available in the area.

Mechanical behavior of epoxy resin with graphite additive subjected to water absorption

Abstract Epoxy resin-based composites find extensive applications across various industries due to their unique mechanical properties. They are commonly used in gas and petrochemical industries for pipes and fittings in transmission lines. The primary objective of this study is to investigate changes in the mechanical properties of epoxy resin-based composites under different environmental moisture conditions. To achieve this, epoxy resin with varying weight percentages of graphite additive (0, 5, 10, 15, and 25 wt%) was used. The water absorption characteristics of the specimens were assessed by immersing samples in potable water (PW), distilled water (DW), a 10 vol% alkaline solution (NaCl), and a 10 vol% acidic solution (HCl), following ASTM standards. Both dry and wet samples were examined for various mechanical strengths. The results indicate that, for all weight percentages of graphite additive, water absorption follows the increasing order: NaCl < PW < DW < HCl, as compared to the blank resin case. In terms of mechanical testing, increasing the weight percentage of graphite additive resulted in a 24 % decrease in Barcol hardness and a 39 % decrease in impact strength, while the hot deflection temperature (HDT) increased for 5 wt% and showed no significant effects for the other cases.

INVESTIGATION OF MECHANICAL AND PHYSICAL PROPERTIES OF DATE PALM STEM FIBRE REINFORCED EPOXY COMPOSITES

The growing demand for sustainable materials, particularly date palm stem fibre (DPSF), has garnered attention in the area of engineering applications due to its advantageous traits. Its composites offer distinctive characteristics such as satisfactory mechanical properties, low density and a cost-effective production. This study examines the mechanical characteristics of epoxy (LY-556) composites reinforced with DPSF. A range of composite configurations with different compositions and fibre loadings were meticulously crafted, using a hand lay-up technique. The research meticulously examines DPSF and epoxy composites with loadings of (10, 15, 20, and 25) w/%, comprehensively characterizing their flexural, tensile, impact and water-absorption behaviours. Across the varied compositions, the characteristics of flexural strength, tensile strength, impact strength and water absorption are thoroughly analysed. The conclusive findings underscore optimal enhancements in the flexural, tensile and impact strengths achieved with the DPSF loading of 20 %. This empirical understanding bears significance for designing natural fibre reinforced composites with superior mechanical attributes, reaffirming DPSF’s potential as a valuable reinforcement in modern engineering applications.

High pressure salt water and low temperature effects on the material performance characteristics of additive manufacturing polymers

The effects of salt water exposure at deep ocean depth pressures when coupled with low temperatures on the material characteristics of three unique additively manufactured polymers has been investigated through a detailed experimental approach. The polymers in the study were manufactured utilizing both Vat Photopolymerization and Material Extrusion printing techniques. The Material Extrusion process was utilized to produce material specimens of Stratasys ULTEM 9085 and Markforged Onyx while the Vat Photopolymerization process was used to produce specimens of Accura ClearVue. The ULTEM 9085 and Markforged Onyx are filament based polymers and the ClearVue is a liquid based resin. The specimens were first submerged in a high pressure, salt water bath of 3.5% NaCl solution at 34.5 MPa (5000 lb/in2) for a total exposure time of 60 days to determine the water absorption characteristics. Subsequent to the salt water exposure at high pressure, the specimens were evaluated to determine changes in tension, compression, flexure, and in-plane fracture properties. To determine the effects of water saturation and low temperature coupling, the mechanical testing was performed at temperatures of 20 °C, 0 °C and −20 °C in both dry and saturated conditions. Additionally, non-destructive testing in the form of TeraHertz and FIRT imaging was conducted to analyze the physical material changes through the thickness of the material due to the saline water absorption. To quantify the change in material storage and loss moduli properties, Dynamic Mechanical Analysis (DMA) characterization was performed on each of the AM polymers in dry and saturated states. The DMA testing also quantified changes in the Glass Transition Temperature because of salt water exposure. In summary, The current study investigates the effects of coupled long term/high pressure salt water exposure with low temperatures on the mechanical and material characteristics of three unique AM polymers by: (1) immersing the materials in a salt water solution at 34.5 MPa for 60 days, (2) Conducting post exposure mechanical testing on the materials at 0 °C and −20 °C with comparisons to 20 °C testing on dry specimens, and quantifies changes in material properties through DMA experiments. The results from all testing in the study show that high pressure salt water exposure when coupled with low temperatures has unique effects on each of the materials considered in the study and careful consideration to each parameter must be given based on the material type when components will be employed in marine operations.

Impact of fiber diameter on mechanical and water absorption properties of short bamboo fiber-reinforced polyester composites

Abstract This study aims to investigate the effect of fiber diameter on the mechanical and water absorption characteristics of short bamboo fiber-reinforced polyester composites. Three different fiber sizes (180–250 µm, 250–500 µm, and 700–1000 µm) were used to prepare composites with varying fiber loadings of 10 wt.%, 20 wt.%, and 30 wt.%. The fabricated composites were cut to standard dimensions, and tension tests, impact tests, and water absorption tests were performed. Reproducible results were obtained, revealing that using fibers of smaller diameter (180–250 µm) increased the tensile strength of the composite by 20 % compared to composites with larger diameter fibers (700–1000 µm), while the tensile modulus showed a 22 % enhancement with decreasing fiber diameter. Composites with larger diameter fibers exhibited more defects (voids and matrix detachment), as revealed by SEM analysis of fractured surfaces. The impact strength of composites with a diameter size of 700–1000 µm increased by 33 % compared to composites reinforced with the smallest fiber diameter. Water absorption of the composites was also studied by long-term immersion in water, showing that water intake was high initially, reaching a saturation point after a certain time interval. The absorbed water values indicated that composites with the smallest diameter (180–250 µm) showed maximum water intake due to the creation of more water intake sites (increased interfacial area), while composites with the largest diameter fibers (700–1000 µm) exhibited the least water absorption as the interaction region between fibers and matrix was reduced.

Performance of concrete containing sulfate-eroded recycled aggregates

The original concrete subjected to environmental attack will change the properties of recycled aggregates, thereupon affecting the performance of recycled concrete. However, there is a lack of research that considers such impact. This study aims at providing knowledge on the performance of concrete containing sulfate-eroded recycled aggregates considering the effect of erosion age on workability, water absorption, mechanical, microstructure and interface characteristics. Results show that the incorporation of sulfate-eroded recycled aggregates increases the slump by up to 21.7%, and decreases the water absorption by approximately 9.9% given an erosion age of 126 days. With recycled aggregates under a long-term sulfate attack, the slump decreases and water absorption increases, which is due to the increased porosity of the attached old mortar on the recycled aggregate. Similarly, adding sulfate-eroded recycled aggregates leads to significant changes in compressive, split-tensile and flexural strength of concrete as well, with a sudden change occurring at an erosion age of 126 days. In addition, a large amount of erosion products, i.e., ettringite, remain in the residual mortar of the long-term eroded recycled aggregate, which results in excessive pore filling and causes more defects. Furthermore, it has a negative impact on the interface bond between recycled aggregates and the new mortar by reducing the proportion of C-S-H in the interface hydrates.

Toughness improvement of low strength ceramsite lightweight concrete by polypropylene fiber and recycled rubber particle

In order to improve the crack resistance toughness and investigate the capillary water absorption (sorptivity) characteristics of ceramsite lightweight concrete (CLWC), the current study has examined the performance characteristics of locally accessible polypropylene (PP) fiber and rubber-reinforced lightweight concrete. An investigation on CLWC's strength, ductility, and sorptivity was addressed in this research. This study examined how fiber and rubber affect CLWC characteristics. Thus, the experiment maintained concrete mix design and fiber and rubber properties while varying fiber and rubber dosages from 0.05% to 0.15% and 0.5–1.5%. Multiple tests on CLWC specimens showed promising compressive, flexural, and toughness results. In the sorptivity test, fibers inhibit CLWC water absorption, assessing lightweight concrete porosity and permeability. SEM examined the ceramsite, rubber, fiber, and mortar interaction microstructure. Notably, strength capacity significantly improved compared to conventional lightweight concrete. Beam flexure testing indicated a maximum 62.79% toughness enhancement. Additionally, the first-crack load increased by 31.83%, and the ultimate load increased by 32.34% over control beams. The macro crack strength of interconnecting structures is improved by fiber and rubber. Several energy dissipation pathways gave ceramsite lightweight materials enhanced flexural toughness.

Effect of Silica Fume Concentration and Water–Cement Ratio on the Compressive Strength of Cement-Based Mortars

This study investigated how the water–cement ratio and silica fume concentration affect the compressive strength of cement mortars. This comprehensive study delved into the intricate interplay between water–cement ratio and silica fume concentration, examining their influence on cement-based mortars’ compressive strength and water absorption characteristics. The silica fume concentration was investigated, ranging from 5% to 15% of the cement weight. The investigation employed two distinct mixing techniques, mixing cement and silica fume, before extracting appropriate samples; alternatively, a magnetic stirrer was used to prepare samples by dissolving silica fume in water. The cement mortars were also prepared with three different water–cement ratios: 0.44, 0.47, and 0.5. The interesting findings of compressive tests illuminated a consistent trend across all curing days and mixing methods—a reduction in the water–cement ratio corresponded with a notable increase in compressive strength. However, it is essential to note that the influence of the mixing method on the compressive strength of cement-based mortars is based on the water–cement ratio. The results show that by using the suggested technological method, it was observed that samples prepared with water–cement ratios (W/C) of 0.47 and 0.44 exhibited higher compressive strengths compared to those prepared using the well-known standard mixing method. The compressive test results underscored that the water–cement ratio reduction consistently enhanced the compressive strength in every combination of curing days and mixing techniques. Furthermore, this reduction in the water–cement ratio was correlated with a decrease in water absorption of the mortar. Conversely, the water–cement ratio itself played a pivotal role in defining how the mixing technique affected the compressive strength and water absorption of cement-based mortars. This multifaceted exploration underscores the nuanced relationships between key variables, emphasizing the need for a comprehensive understanding of the intricate factors influencing the mechanical and absorptive properties of cement-based materials.

In Situ Real-Time Atomic Force Microscopy Observations of Chain Mobility at Polymer/Water Interfaces of Poly(methyl methacrylate), Poly(2-hydroxyethyl methacrylate), and Poly(2-methoxyethyl methacrylate) Films in Water.

Polymer materials are widely used in water or in contact with an aqueous environment. However, evaluating the chain mobility, a crucial parameter, at a polymer-water interface is challenging. In this study, we, for the first time, observed poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(2-methoxyethyl methacrylate) (PMEMA) film surfaces in water via in situ real-time atomic force microscopy (AFM) in tapping mode and quantified the chain mobility. The average displacement between adjacent images (nm/8.75 min) was evaluated using particle image velocimetry. The displacement of PMMA, which has a high bulk glass-transition temperature (Tg) (108 °C) and exhibits limited water absorption, was low both in air (0.54 nm/8.75 min) and water (0.86), while PHEMA, which has a high bulk Tg (99 °C) and exhibits high water absorption, exhibited low mobility in air (0.40) but two orders of magnitude higher mobility in water (60). PMEMA, which has a low bulk Tg (14 °C) and exhibits limited water absorption, already started to move in air (4.5), and its mobility moderately increased in water (20). These behaviors were reasonable, considering the bulk Tg and water absorption characteristics of the polymers. Further, the chain mobility in water was compared with that of dried samples at high temperatures in air. The mobility of PMMA, PHEMA, and PMEMA in water corresponded to that of the dried samples observed in air below the surface Tg (97 °C) for PMMA, at ∼125 °C for PHEMA, and at ∼35 °C for PMEMA. In situ real-time AFM analysis of polymer materials in water is an effective method for evaluating the chain mobility at the polymer/water interface.

Insights into water absorption characteristics of various waste-based inorganic additives and their application for soil stabilization

Cement is the most important binding agent used in soil stabilization and significantly improves the strength and compressibility of soils. However, owing to the significant environmental and socio-economic impact of cement production, alternative, low-carbon binders are increasingly being sought. Among them, waste-based inorganic additives used in construction provide sustainable soil treatment materials and reduce the need for landfills. Effective mud stabilization depends on the type of stabilizers and their mineralogical setup, as well as an understanding of their water absorption capacity. Therefore, this study investigated the factors influencing the water absorption characteristics of waste-based additives, including paper sludge ash (PSA), palm kernel shell ash (PKSA), rice husk ash (RHA), coal fly ash, hemihydrate gypsum, limestone powder, and basalt rock powder (BRP). The water absorption capacity (Wab) of each additive represents the amount of water absorbed per gram evaluated via the suction filtration method. The long-term water absorption capacities of the waste additives were compared with a conventional additive, blast furnace cement class B (BFCB). Although PSA, PKSA, and RHA absorbed more water than BFCB under short-term curing, BFCB exhibited the highest Wab under long-term curing. PSA, PKSA, and RHA had a water absorption capacity at 4 h (Wab)t = 4h of 74.5%, 107.3%, and 62.9%, respectively, whereas that of BFCB was 37.4%. In contrast, after 168 h, the water absorption capacity of BFCB increased to 126.1%. These evaluated water absorption capacities were categorized into immediate and time-dependent stages. Mercury intrusion porosimetry, X-ray diffraction (XRD), and scanning electron microscopy investigations were conducted to investigate the influence of factors such as porosity and hydration of the different additives on water absorption capacity. The results showed that porosity characteristics affect the immediate water absorption capacity, and hydrate formation contributes to increased water absorption during curing. The waste additives PSA, PKSA, and RHA with irregular surfaces and pores were highly porous and exhibited a high immediate water absorption capacity (Wab)t = 4h, unlike the additives with flat surfaces and less irregularities with lower (Wab)t = 4h. The XRD investigation revealed that the presence of ettringite and calcite contributed to increased water absorption during curing for PSA, PKSA, and BFCB. The generation of needle-like ettringite could promote a denser microstructure in PSA, PKSA, and BFCB, thus further improving Wab during curing. Finally, using cone index strength, we explored the effective application of waste-based additives as soil stabilizers, attempting to predict the effect of water absorption capacity on the properties of treated soil. The stabilizer addition ratio (A) and Wab of the waste additives were found to be essential indicators for predicting the strength development of treated clays. A clear correlation was observed between the cone index (qc) and parameter β(t), which is derived from Wab and A, of the treated clays.

Preparation and performance analysis of polyamide-based rapid repair material for asphalt pavement shallow groove

In order to effectively remedy shallow grooves on asphalt pavements, this study presents an innovative solution, termed Polyamide-based Asphalt Pavement Shallow Groove Rapid Repair Material (PA-SGRRM). This material employs polyamide 6 (PA6) as the matrix resin, in conjunction with polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), and maleic anhydride-grafted polyethylene-octene copolymer (POE-g-MAH). It is manufactured through an extrusion granulation process. At the outset, a molecular dynamics approach was employed to assess the compatibility of the primary constituents and the adhesion between the matrix resin and asphalt, confirming the rationale behind the material selection. Subsequently, the orthogonal experimental design method was utilized to investigate the influence of design parameters (POE-g-MAH content, PP content, and EVA content) on the flexural strength, tensile strength, low-temperature toughness, and melt flow rate of PA-SGRRM. Following this, we prepared samples with the optimal proportions of EVA and POE-g-MAH and conducted a separate analysis to evaluate the impact of PP on the saturated moisture content of PA-SGRRM. Finally, we employed Scanning electron microscopy (SEM) to observe the microstructures of the low-temperature fracture surface and ambient temperature tensile fracture surface of the PA-SGRRM and employed Fourier transform infrared spectroscopy (FTIR) to deduce the primary chemical reactions occurring within the PA-SGRRM. The results demonstrated that POE-g-MAH played a crucial role in enhancing the compatibility of the simulated hybrid system consisting of PP and PA6. Additionally, it was observed that adhesion between PA6 and asphalt existed, with a gradual decrease as temperature rose. The content of POE-g-MAH and PP were the two primary parameters influencing the performance of PA-SGRRM. POE-g-MAH exerted a significant adverse impact on the flexural strength, tensile strength, and melt flow rate of PA-SGRRM, while substantially improving its low-temperature toughness. The PP positively reduced the water absorption characteristics of PA-SGRRM. Based on the experimental results, the optimal combination of design parameters for PA-SGRRM is recommended.

Characteristics of Fibre-Reinforced Cement-Sand Blocks with Quarry Dust as Replacement for Sand

The present investigation delved into the mechanical performance of fibre-reinforced cement-sand blocks with quarry dust as a replacement for sand. The introduction of fibres and quarry dust in the matrix is an attempt to achieve higher performance with available cement content and reduce the utilization of natural sand to improve the sustainability of the product. The experimental programme attempted to study the influence of quarry dust on the density, compressive strength, water absorption, sorptivity, and efflorescence characteristics of the blocks. The parameters considered include quarry dust (QD) content (replacement of sand from 0% to 100% in increments of 20%), a constant fibre content of 0.5%, and a constant water-cement ratio of 0.5. An attempt was also made to compare the strength performance of the blocks with various code requirements as well as results from similar previous investigations. The replacement of sand with QD resulted in a reduction in the density of the blocks from 2365 kg/m3 to 2008 kg/m3. The results of the investigation revealed that 60% quarry dust replacement of natural sand developed the maximum strength of the blocks. After 28 days of curing, blocks with up to 60% QD replacement were able to produce strength more than 16 MPa. The water absorption increased only marginally from 5.52% to 5.83% for 60% QD replacement. Moreover, the blocks were able to meet the requirements of all the different types of blocks as stipulated by Bureau of Indian Standards including stabilized soil blocks, concrete solid blocks, concrete hollow blocks, lime-based blocks, and lime-flyash blocks of class up to 17.5.