Increasing Resin Content Research Articles

Physical and mechanical properties of fiberboard produced with shredded waste office paper

This study investigated the effects of shredded waste office paper as a raw material on the physical and mechanical properties of fiberboard. Two amounts of urea formaldehyde (UF) resin (10 and 15%) and five shredded waste office paper/wood fiber mixing ratios (0/100, 25/75, 50/50, 75/25, and 100/0) were selected. The findings showed that all characteristics of boards were improved with an increase in resin content at various wastepaper participation ratios. The 15% UF-bonded board with 100% wood fiber had the highest modulus of rupture (MOR) value, but there was no statistically significant difference between it and the board with 50% wastepaper. The modulus of elasticity (MOE) values of the 15% UF-bonded boards increased as the wastepaper participation ratio increased, and the highest was obtained from the board with 75% wastepaper. The highest internal bond (IB) strength value was also recorded from the 15% UF-bonded board with 50% wastepaper. This was due to the presence of sufficient bonding potential and smoother surfaces in the shredded wastepaper, which allowed for a synergistic interaction between the wastepaper and wood fiber.

THE EFFECT OF TREATING HEAVY OIL WITH ISOPROPYL ALCOHOL ON THE COMPOSITION AND STRUCTURE OF RESINS

The effect of heavy oil treatment with isopropyl alcohol (IPA) for 8 h at a temperature of 25-100 °C on the composition and structure of resins is investigated. The objects of investigation were heavy oil from the Zyuzeevskoye field (the Republic of Tatarstan) and resins isolated from this oil. It is established that the resin content increases by almost 3 wt% as a result of heavy oil treatment with IPA at 100 °C. It is shown than an increase in the temperature of oil - IPA (20 wt%) mixture treatment from 25 to 100 °C causes an increase in sulphur and oxygen content in resins by 0.5 and 0.8 wt%, respectively, and a decrease in the Н/С atomic ratio from 1.40 to 1.38. The aromaticity factor of resins increases by 0.17 %, while the fraction of aliphatic carbon decreases. It is concluded that oil treatment with isopropyl alcohol, aimed at a decrease in the content of resinous and asphaltenic substances, is unreasonable because it causes unfavourable formation of the additional amount of resins.

From Bin to Binder: Unleashing Waste Butter’s Potential as a Pioneering Bio-Modifier for Sustainable Asphalt Engineering

Exploring the interface of environmental sustainability and civil infrastructure development, this study introduces waste butter (WB), a byproduct of animal fat processing, as a novel bio-modifier in asphalt production. This approach not only recycles animal waste but also charts a course for sustainable infrastructural development, contributing to a reduced environmental impact and promoting circular economy practices. The experiments incorporated varying WB concentrations (e.g., 3%, 6%, and 9% by weight of binder) into standard AP-5 asphalt, employing advanced analytical tools for comprehensive characterization. These included thin-layer chromatography–flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The critical properties of the asphalt blends, such as penetration, softening point, viscosity, ductility, rutting factor (Dynamic Shear Rheometer), and thermal susceptibility (Penetration Index, Penetration–Viscosity Number), were assessed. FT-IR analysis indicated negligible chemical alteration with WB addition, suggesting predominantly physical interactions. TLC-FID showed a decrease in aromatic and asphaltene components but an increase in resin content, highlighting the influence of WB’s fatty acids on the asphalt’s chemical balance. The colloidal instability index (IC) confirmed enhanced stability due to WB’s high resin concentration. Meanwhile, SEM analysis revealed microstructural improvements with WB, enhancing binder compatibility. TGA demonstrated that even a minimal 3 wt. % WB addition significantly improved thermal stability, while the DSC results pointed to improved low-temperature performance, reducing brittleness in cold conditions. Rheologically, WB incorporation resulted in increased penetration and ductility, balanced by decreased viscosity and softening point, thereby demonstrating its multi-faceted utility. Thermal susceptibility tests emphasized WB’s effectiveness in cold environments, with further evaluation needed at higher temperatures. The DSR findings necessitate careful WB calibration to meet Superpave rutting standards. In conclusion, this research positions waste butter as a superior, environmentally aligned bio-additive for asphalt blends, contributing significantly to eco-friendly civil engineering practices by repurposing animal-derived waste.

Preparation and Characterization of Bismaleimide-Resin-Based Composite Materials.

This study utilized bismaleimide (BMI) resin, reinforced with introduced ether bonds, as a binding matrix, in combination with silicon carbide (SiC), for the fabrication of composite materials. A thorough investigation was conducted to assess the influence of diverse processing parameters on the mechanical properties and high-temperature thermo-oxidative stability of these composites. Experimental results indicate a notable improvement in the mechanical properties of the composites upon the incorporation of ether bonds, in contrast to their unmodified counterparts. The variation in performance among composites with different ratios and molding densities is apparent. Within a certain range, an increase in resin content and molding density is correlated with improved bending strength in the composites. With a resin content of 27.5 vol% and a molding density of 2.31 g/cm3, the composite achieved a maximum flexural strength of 109.52 MPa, representing a 24% increase compared to its pre-modification state. Even after exposure to high-temperature heat treatment, the composites displayed commendable mechanical properties compared to their pre-ether bond modification counterparts, maintaining 74.5% of the strength of the untreated composites at 300 °C. The scanning electron microscopy (SEM) microstructures of composite materials correlate remarkably well with their mechanical properties.

Effect of Resin Content on the Structure, Water Resistance and Mechanical Properties of High-Density Bamboo Scrimbers.

Bamboo scrimber is acknowledged for its eco-friendly potential as a structural material. Its properties are significantly affected by both its density and resin content, but the effect of resin content on the properties under high density is not yet known. In this study, the microstructure, water resistance, mechanical properties, and thermal stability of bamboo scrimbers with varying resin content at a density of 1.30 g/cm3 were investigated. The results unearthed that phenolic resin assisted in the densification of bamboo cells during hot pressing, and a higher resin content could effectively reduce the cracks in the scrimber. The inherent cellulose I structure remained unaffected, but an increase in resin content led to a noticeable decline in crystallinity. Additionally, an increase in resin content pronouncedly improved the water resistance and dimensional stability of bamboo scrimbers. The water absorption and thickness swelling were as low as 9.67% and 7.62%, respectively. The modulus of rupture (MOR) exhibited a marginal increase with the amount of resin, whereas the compressive strength and short-beam shearing strength first increased and then decreased. Their peak strengths were 327.87 MPa at a resin content of 15 wt.%, and 168.85 MPa and 25.96 MPa at 11 wt.%, respectively. However, phenolic resin accelerated the thermal decomposition of bamboo scrimbers, and more resin worsened the thermal stability. These research outcomes offer a dual advantage, providing both a theoretical foundation and concrete data that can inform the production and practical application of high-density bamboo scrimbers.

Effect of resin content on the water-resistant, mechanical, and thermal properties of scrimber made from radiata pine wood (Pinus radiata D. Don)

ABSTRACT Scrimber is processed by laminating wood fiber mats impregnated with phenolic resin under hot pressing. One of its essential components is phenolic resin. In this study, the effect of phenolic resin content on the structural, water-resistant, mechanical, and thermal properties of pinewood scrimbers was investigated. Results showed that phenolic resin facilitated the collapse of cell walls at low pressure during lamination, and higher resin content markedly reduced cell wall cracking. The cellulose I structure of pinewood remained intact, whereas its crystallinity decreased as resin content increased. Moreover, the resin significantly improved water resistance and dimensional stability; an increase in resin content led to a more pronounced improvement. The water absorption in 35 h at a resin content of 15 wt.% was approximately 1/10 of that at 9 wt.%. Scrimbers with a resin content of 9 wt.% exhibited a 50% increase in modulus of rupture (MOR) and a more than 1.4-fold increase in modulus of elasticity (MOE) relative to that of solid pine wood. As the resin content increased, MOR remained stable, MOE slightly decreased, and shearing strength increased. In addition, phenolic resin promoted the thermal degradation of scrimbers, and the higher resin content in the scrimber led to better thermal degradation.

High-performance bamboo scrimber composite prepared from heat-treated Bambusa chungii units with different resin contents for outdoor use

In this study, bamboo scrimber composites (BSCs) was prepared using two types of bamboo units and a phenolic (PF) resin, and the effect of heat treatment on water resistance and mechanical properties was investigated. The results showed that heat treatment significantly improves dimensional stability but degrades mechanical performance owing to a change in chemical composition and decreased porosity. Furthermore, the water resistance increases with an increase in resin content. The WAR and TSR of BSC-T-II reached 3.74% and 3.72%, respectively, at 25 wt% resin content. Heat treatment modification does not significantly improve the flame retardancy of BSCs, and future studies should consider treating bamboo with flame retardants. The BSCs have the potential to replace nonrenewable synthetic materials for outdoor use by optimizing heat treatment, bamboo unit processing, and resin content.

Tailoring layered Csf/SiBCN composites with pseudoplastic fracture behavior: Strengthening and toughening mechanisms

AbstractThe layering process using phenolic resin coupled with pressureless sintering technique was explored to prepare short carbon fiber‐reinforced SiBCN composites (Csf/SiBCN). The effect of phenolic resin content on the microstructure and mechanical properties of Csf/SiBCN was mainly studied. Results suggest that the addition of phenolic resin can appropriately improve density and flexural strength and reduce total pore volume of the composites because phenolic resin can partly consolidate SiBCN powders to promote shaping via low‐temperature pressureless sintering. As the phenolic resin content increases, the fracture behavior changes from delamination fracture to monolithic fracture, thereby reducing fracture displacement. The reason for this performance is that the interlayer bonding is enhanced to hinder crack propagation along the layers.

Evaluation of Asphalt Aging Using Multivariate Analysis Applied to Saturates, Aromatics, Resins, and Asphaltene Determinator Data.

Asphalt is subjected to aging, leading to physical and chemical modifications reducing its performance. Recently, the Western Research Institute developed the SAR-AD method that allowed the separation of asphalt into eight fractions (saturates, aromatics 1, aromatics 2, aromatics 3, resins, asphaltenes 1, asphaltene 2, and asphaltenes 3). In this work, this analytical method was used to study asphalt aging processes in greater detail. Several asphalts of different origins and reconstituted blends were studied. These products were aged during several durations using a PAV (pressure aging vessel) between 0 and 48 h to collect information on the evolution of each SAR-AD fraction. Different evolutions were observed according to the initial asphalt composition and SAR-AD fraction studied. The saturated subfamily seemed to be slightly impacted by aging. The amount of three aromatic subfamilies decreased with a larger decrease of aromatics 3 than aromatics 2, itself larger than aromatics 1. The content of the resin subfamily increased after 48 h of PAV aging. The asphaltene 1 and asphaltene 2 subfamilies exhibited an increasing trend. Moreover, the quantity of asphaltenes 2 created seemed to correlate to the initial asphaltene content. The evolutions of the asphaltene 3 subfamily were not significant. However, a specific behavior was highlighted for the most asphaltenic sample. For this specific sample, the increase of resin content was weaker, the mass of asphaltenes 1 decreased, and the amount of asphaltenes 3 increased during aging. Given the large amount of data generated, an original approach was developed to statistically identify the most affected SAR-AD subfamily and determine correlations among them. Two PCAs (Principal Component Analysis) were conducted on asphalt SAR-AD data. This statistical analysis indicated two generic asphalt aging pathways. The first aging pathway could be the conversion of aromatics 2 into resins, with no evidence that resins could contribute to asphaltene creation. The second aging pathway showed the conversion of aromatics 3 directly into asphaltenes 2. These two aging pathways highlighted that the conversion of molecules in more polar ones during aging could skip SAR-AD subfamilies, meaning that asphaltenes could be created without involving resins.

Enhanced flowability and film properties of ultrafine powder coatings modulated by modified flow additive

Ultrafine powder coatings have superior film performance but poor flowability due to the high interaction between particles, which can be improved by the addition of inorganic flow additives. However, the improvement is limited and more importantly, the film performance deteriorates because of their incompatibility with the organic coating resin. In this study, a resin encapsulation approach was proposed to modify the commercial inorganic flow additives for the improvement of powder flowability and maintaining film quality. The effects of resin content and additive dosage on the flowability characterized by angle of repose (AOR) and avalanche angle (AVA), and film performance characterized by gloss, seed density and surface roughness were systematically investigated in two powder coating systems. It was found that the encapsulation of additives with the same resin of the host powder coating can enhance both flowability and film properties, compared to commercial nano-silica. With the increase of resin content, both the AOR and AVA first decrease to a minimal value at resin content of 5 % to 10 % and then increase when applying excessive resin encapsulation. Similar to the effect of resin content, there is also an optimal additive dosage at 0.3 to 0.5 wt% for the best flowability, while excessive additives lead to “bridge effect”. The negative effect raised by the additives on film quality can be mitigated by resin encapsulation. Higher gloss and lower roughness are obtained at larger resin content, while the smallest seed density is at resin content of 10 %. The study provides an effective and facile way to ameliorate the function of the flow additive and enhance the properties of powder coating films.

Effect of Resin Content on the Surface Wettability of Engineering Bamboo Scrimbers

Bamboo scrimber refers to a lignocellulosic structural material, which is usually attacked by water, ultraviolet radiation and fungus. Surface coating is an effective way to protect it, and its coating properties depend on surface wettability. In this study, the surface wettability of bamboo scrimbers with varying resin content was investigated via the comprehensive analysis of surface roughness, surface contact angle, surface free energy, surface chemical composition and coating properties. The resultant scrimbers had a similar profile with low roughness. Their surface was hydrophilic, but the hydrophilicity decreased with the increase in resin content. High resin content gave rise to low total free energy, in which the Lifshitz–van der Waals component was dominant and it decreased with the increasing resin content. Meanwhile, the ratio of the electron-accepting component to the electron-donating component becomes higher. This was due to the decreasing hydrophilic groups (e.g., -OH and -COOH groups) and the increasing oxygen-free groups (e.g., C-H and -CH2 groups) on the scrimber surface. The resin content affected the adhesion by decreasing the surface wettability, but the coating adhesion still reached the level of 2 for all bamboo scrimbers. The results will provide a theoretical reference for the surface coating of bamboo scrimbers in the structural application for good coating durability.

Temperature Dependence of Electrical Resistance in Carbon Nanotube Composite Film during Curing Process.

Carbon nanotube (CNT) film possesses excellent mechanical and piezoresistivity, which may act as a sensor for process monitoring and reinforcement of the final composite. This paper prepared CNT/epoxy composite film via the solution dipping method and investigated the electrical resistance variation (ΔR/R0) of CNT/epoxy composite film during the curing process. The temperature dependence of electrical resistance was found to be closely related to resin rheological properties, thermal expansion, and curing shrinkage. The results show that two opposing effects on electrical resistivity occur at the initial heating stage, including thermal expansion and condensation caused by the wetting tension of the liquid resin. The lower resin content causes more apparent secondary impregnation and electrical resistivity change. When the resin viscosity remains steady during the heating stage, the electrical resistance increases with an increase in temperature due to thermal expansion. Approaching gel time, the electrical resistance drops due to the crosslink shrinkage of epoxy resin. The internal stress caused by curing shrinkage at the high-temperature platform results in an increase in electrical resistance. The temperature coefficient of resistance becomes larger with an increase in resin content. At the isothermal stage, an increase in ΔR/R0 value becomes less obvious with a decrease in resin content, and ΔR/R0 even shows a decreasing tendency.

Role of binder in controlling the noise and vibration performance of brake-pads

Although extensive research has been carried out for predicting and mitigating brake noise problems over the past decades, it is still challenging to predict its occurrence due to the complex nature of the brake system. Friction-induced vibration between the tribo couple (i.e. brake disk-pads) is one of the key players for increasing the noise and vibration issues in the brake system. The composition of friction materials (FMs) (i.e. pads/shoes) controls both tribological and noise-vibration (NV) performance. Binder (i.e. resin) is the heart of FMs which binds all the ingredients firmly and provides strength. A lot is reported on the types and amount of resin on the tribological performance, but no study addresses the noise and vibration performance adequately. This work investigates the role of binder in controlling the NV performance of the Cu-free brake-pads. Four types of copper-free brake-pads were developed with varying content (viz., 6, 8, 10, and 12 wt.%) of phenolic resin as a theme ingredient keeping the parent composition fixed. The natural frequencies and damping ratios for the developed pads were evaluated through experimental modal analysis of the pads. The detailed NV performance was evaluated on the in-house developed brake NV test rig by partly following the SAE J 2521 test schedule. Additionally, friction performance was also studied for different braking conditions. Results revealed that the compressibility, porosity, and damping ratio decreased, whereas hardness and natural frequency increased with the increase in resin content in the brake-pads. Overall, among all the pads, the brake-pad with 6 wt.% resin content proved best for the NV performance.

Effects of Resin Content on Mechanical and Physical Properties of Treated Kenaf Particleboard

Kenaf whole stems were obtained from kenaf plantation located in Chendor, Cherating, Pahang. The stems were cut into small particles with sizes ranging between 0.5 mm to 2.0 mm. Kenaf particles were treated using 2 % NaOH solution. Phenol formaldehyde (PF) adhesive was used to bind the kenaf particles together with resin contents of 8 and 10 %. The objectives of this study were to evaluate the effect of resin content on mechanical and physical properties of treated kenaf particleboard. The boards were cut and tested according to the Malaysian Standard (MS1787:2004) for furniture grade particleboards for use in humid condition. Results showed that the values of modulus of rupture, modulus of elasticity and internal bonding strength increased with an increase in resin content, while thickness swelling and water absorption increased with a decrease in resin content. Kenaf board treated with sodium hydroxide gave the highest value of bending strength and internal bonding strength compared to untreated particleboard which acted as a control board. Although all boards did not achieve the minimum standard values requirement according to the Malaysian standard, kenaf has been proven to have a great potential as raw materials in the particleboard industry. Further studies are needed to improve its properties particularly for exterior applications.

Influence of Resin Content and Density on Water Resistance of Bamboo Scrimber Composite from a Bonding Interface Structure Perspective.

As a new type of green environmental protection material for outdoor use, the water resistance of bamboo scrimber composite (BSC) is crucial—the primary reason for a decrease in water resistance being bonding interface failure. From a bonding interface structure perspective, the influence mechanism of the resin content and density on the water resistance of BSCs remains unknown. Therefore, in this study, BSCs were prepared using Moso bamboo and phenol-formaldehyde resin, and the changes in the macroscopic and microscopic bonding interfaces before and after 28-h water-resistance tests were observed and analyzed. The results showed that the water resistance of the BSC increased with increasing resin content, with higher thickness swelling rates (TSRs) observed at higher densities. Obvious cracks were found at the macroscopic interface after 28-h tests, with higher resin contents leading to fewer and smaller cracks. With increasing density, the longitudinal fissures due to defibering process decreased, having an effect on width swelling rates (WSRs). Furthermore, porosity measurements revealed changes in the microscopic bonding interface; the difference in porosity before and after testing (D-value) showed the same trend as water resistance. Generally, we conclude that the macroscopic and microscopic bonding interface structures are closely related to BSC water resistance.

Use of PET resin and metakaolin in sustainable production of cement mortar

In the 21st century, substantial growth in plastic consumption is observed worldwide, which has led to vast quantities of plastic waste. Polyethene terephthalate (PET) is one kind of plastic that is widely used packaging industry because of its advantages of being light in weight non-reactive to substance. This advantage increases the consumption of PET and leads to another problem of solid waste management. The chemical recycling of PET waste to form a low-cost polymer and used as a binder to replace cement and the mineral addition of metakaolin would be advantages for cement concrete or mortar. In this work, PET resin is prepared with a 30:70 PET to Glycol ratio and further added to 5%, 10% 15% as cement replacement with a curing agent. In addition to this, metakaolin was added by 10%, 20%, and 30% of the volume of cement as supplementary cementing material. The fresh and hardened properties were determined for various mixes. The flow of mortar increases as PET resin content increases. The addition of metakaolin reduces the flowability of mortar. The compressive and tensile strength is determined at 1,7 and 28-days of curing. The 1-day curing compressive strength is 80% of the targeted strength is achieved for 15% resin content specimen with and without metakaolin compared to standard cement mortar specimen. In comparison with compressive strength, the gain in tensile strength is more. As the PET content increases in the mix increases the tensile strength. The durability is assessed by water penetration resistance and abrasion resistance, and it is observed that the addition of 15% PET resin and 20% metakaolin increases the durability. The mix ratio of 1:3 is used; among all the mixes, 15% PET resin and 20% metakaolin content mix are found to be the optimum mix in all testing parameters. The cost analysis is carried out for the same mixture. The addition of PET Resin and Metakaolin reduces the cement consumption by 141 kg/m3 and there by a reduction in the CO2 emissions. It will help to achieve the objective of sustainable development.

Densifying (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high‐entropy ceramics by two‐step pressureless sintering

AbstractA pressureless two‐step sintering method was used to densify high‐entropy carbide (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C, with high density and good mechanical performance. The material was heated up to 2200°C and subsequently soaked at 1900°C for 2–8 h with the incorporation of 2–4 wt.% phenolic resin. With increasing resin content, the large‐sized pores disappeared, and the average grain size decreased. However, with increased holding time from 2 to 8 h, the average grain and pore size did not change significantly, the density increased up to 96.2%, and evident grain growth of graphite was observed. The mechanical properties of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C with 4 wt.% phenolic resin addition and 8 h soaking at 1900°C were measured as follows: flexural strength 361±28 MPa, Vickers hardness 16.0±0.3 GPa, and elastic modulus 426±2 GPa.

MEDIUM DENSITY PARTICLEBOARD USING POSTHARVEST SUGARCANE LEAF STRAW: EFFECT OF RESIN TYPE AND CONTENT, DENSITY AND LAYERS ARRANGEMENT

Medium Density Particleboard (MDP) using sugarcane leaf straw (SLS) particles, a byproduct of the sugarcane harvesting, bonded with synthetic resins (urea-formaldehyde-UF and phenol-formaldehyde-PF) was produced and evaluated. Panels were tested for physical and mechanical properties, according to Brazilian standard ABNT NBR 14810-2 (2018). Variables of two types of resin, two resin contents, two arrangements of board layers and two board densities were analyzed in 12 treatments experimental design. The results grade the panels as Type 2, according to specifications of the Brazilian standard, for internal/dry use. They are also graded as classes M1 and M2 of the ANSI A208.1 (2016) standards for use as industrial MDP. Board density varied from 0.569 to 0.749 g/cm³. Generally, properties improved with the increase of resin content and density. Among the panels bonded with UF the best result was presented with single layer, 12% solids and density of 0.75 g/cm³. Panels glued with 12% PF showed best results of resistance and improved dimensional stability. As an exploratory study, the results are promising and further work is needed to assure the technical use of this agricultural waste, which is usually burned and seen as an environmental burden.

Robotic automated fiber placement of carbon fiber towpregs

ABSTRACT Robotic Automated Fiber Placement (R-AFP) technology was developed to manufacture composite laminates by placing carbon fiber thermoset towpregs, obtained by impregnating 12 K high-strength grade carbon fibers in an epoxy resin system. In order to avoid placement induced defects, a thermographic scanning technique was implemented for on-line quality monitoring of the R-AFP process. The thermal analysis proved to be an effective and quick approach for the real-time detection of deposition defects generated during. The R-AFP process was performed by applying a constant pressure through the compaction roller; different pressure values were investigated. The effect of the resin weight fraction and compaction pressure on the mechanical properties applied by the deposition head during R-AFP of cross-ply laminates was studied. The reduction of the tensile strength and the increase of the elastic modulus with decreasing pressure of the compaction roller was observed. Furthermore, the values of ultimate tensile strength and elastic modulus decrease as the resin content increases. Finally, the three-dimensional topography of surface fracture of tensile samples was investigated by means of the optical and scanning electron microscopy.

A quantitative study on the amount of water-retaining agent based on adhesive-modified red bed weathered soil

Engineering activities can lead to serious soil erosion problems in red bed areas. To overcome their loose structure, low strength and poor water retention, the red bed weathered soil needs to be modified with adhesives and water-retaining agents. At present, on the premise of applying adhesive, there are few studies on the mechanism of water retention agent to improve soil, and the amount of water retention agent in practical engineering is mainly determined by experience, lacking reliable quantitative basis. Herein, the effects of water-retaining agents on soil quality were quantitatively studied in red bed weathered soil modified by a fixed amount of adhesive. By using shear, permeability, porosity and plant growth tests, we show that the shear strength of the modified soils decreased slightly with increasing resin content, while permeability, porosity and water retention increased, and the growth of plant roots was promoted. Additionally, the processes by which these soil agents improve water retention were investigated, and the control mechanism of the optimum addition amount of water-retaining agent based on the soil water storage and aggregate size was revealed by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) images, and the optimal water-retaining resin dosage for red bed weathered soil modification is proposed. This study provides a quantitative basis for determining water-retaining agent dosage in the red bed areas of South China and similar areas.