Next Article in Journal
From Motion to Form: Systematizing Motion-Data Processing for Architectural Generative Design
Previous Article in Journal
Evidence-Based Sensory Architecture Applied to the Design of Therapeutic Centers for Children and Adolescents with Autism Spectrum Disorder
Previous Article in Special Issue
Numerical and Theoretical Investigation into the Global Stability Behaviour of Glulam Gridshells Stiffened by Prestressed Cables
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Buildings
Volume 16
Issue 8
10.3390/buildings16081491
buildings-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Effect of Paraffin and Vinyl Acetate Ethylene (VAE) Emulsions on the Waterproofing and Mechanical Properties of Fiber-Reinforced Modified Gypsum (FRMG) Matrix

by
Zhenxing Li
1,2,3,*,
Zuohua Li
1,*,
Shaohua Rao
2,
Dongning Li
2,*,
Dejing Lu
2,
Huaitao Zhu
2,
Changyuan Liu
3,
Jianzhe Shi
4,* and
Xin Wang
3,*
1
School of Intelligent Civil and Ocean Engineering, Harbin Institute of Technology, Shenzhen 518055, China
2
Shenzhen Public Housing Group Co., Ltd., Shenzhen 518000, China
3
Key Laboratory of C & PC Structures Ministry of Education, Southeast University, Nanjing 210096, China
4
College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
*
Authors to whom correspondence should be addressed.
Buildings 2026, 16(8), 1491; https://doi.org/10.3390/buildings16081491
Submission received: 3 March 2026 / Revised: 25 March 2026 / Accepted: 27 March 2026 / Published: 10 April 2026
(This article belongs to the Special Issue The Latest Research on Building Materials and Structures)
Browse Figures
Versions Notes

Abstract

Gypsum-based materials are widely used in construction but suffer from poor water resistance and durability, limiting their application in moisture-prone environments. While fiber-reinforced modified gypsum (FRMG) improves mechanical performance, the lack of systematic research on waterproofing strategies and their influence on both durability and strength remains a key challenge. This study investigated three waterproofing methods: surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of vinyl acetate ethylene (VAE) emulsion. The workability, water absorption, mechanical properties, contact angle, and microstructure of the FRMG matrix were analyzed. The results showed that surface coating provided only short-term waterproofing. Internal incorporation of paraffin emulsion reduced water absorption but weakened mechanical performance. In contrast, VAE emulsion formed continuous polymer films that filled pores, significantly reducing water absorption while improving flexural and compressive strength, with optimal performance observed at a 6% dosage. In addition, increasing emulsion content enhanced hydrophobicity. These results indicate that VAE-based internal modification is an effective approach to improving the durability and performance of gypsum-based materials, providing guidance for their application in interior wall systems and prefabricated building components.

1. Introduction

Gypsum, the hydrated form of calcium sulfate (CaSO4), exists primarily in two forms: anhydrite gypsum (CaSO4·2H2O) and hemihydrate gypsum (CaSO4·0.5H2O) [1]. Gypsum-based materials have found broad application in the construction industry owing to advantageous properties, including low weight [2], ease of handling [3], fire resistance [4], and environmental compatibility. In modern sustainable construction, gypsum is increasingly utilized in prefabricated components and 3D printing applications due to its low carbon footprint compared to Portland cement [5]. However, the mechanical brittleness of pure gypsum often leads to sudden structural failure, necessitating the development of high-performance modified systems [6]. Similar to other brittle geological or cementitious materials, the internal fracture evolution and subsequent mechanical deterioration under environmental impacts remain a significant challenge for ensuring structural integrity [7].
The addition of mineral admixtures involves incorporating materials like cement [8], fly ash [9], lime [10], and mineral powder into the gypsum matrix, which react to form substances such as ettringite [11,12], thus enhancing the water resistance of the gypsum matrix [13,14]. The fiber-reinforced gypsum (FRG) matrix is an innovative material designed to overcome these limitations. Additionally, the introduction of fibers further enhances the toughness of the matrix, enabling a synergistic optimization of its mechanical properties [15,16]. Recent studies have explored the use of various synthetic and natural fibers to arrest crack propagation, yet the interfacial bond between these fibers and the gypsum matrix remains a critical factor in determining the overall ductility of the composite [6].
However, the inherent hydrophilic nature and porous microstructure of the gypsum matrix make it highly susceptible to moisture infiltration [17]. From an applied engineering perspective, gypsum materials frequently encounter issues such as strength loss exceeding 40% when exposed to high humidity or direct water contact [18]. Although the formation of ettringite has provided some enhancement in water resistance [19], the improvement remains limited. Furthermore, the addition of fibers facilitates capillary action, allowing moisture to penetrate more easily into the interior [20]. This not only severely limits the durability but also restricts widespread application in damp or moisture-rich environments [21].
Fibers can enhance the mortar/gypsum toughness, and this intrinsic compatibility enables basalt fibers to function as an effective reinforcement phase, thereby arresting crack initiation and promoting the long-term structural integrity of the mortar/gypsum matrix [22]. Moreover, surface treatments of fibers, such as silane coupling agents or sizing applied to basalt fibers, play a crucial role in enhancing the interfacial shear strength (IFSS) between the fiber and the matrix [23], thereby preventing premature fiber pull-out and facilitating efficient stress transfer [24]. Such modifications are essential for optimizing the post-cracking toughness of brittle gypsum composites [25]. However, fibers simultaneously create preferential pathways for water ingress, thereby introducing a fundamental contradiction between mechanical reinforcement and waterproofing performance [26].
Currently, four primary approaches are employed to enhance water resistance [27,28]: ① Surface coating, ② Internal incorporation, ③ Mineral admixtures, and ④ Enhancement of matrix compactness. Surface coating can temporarily inhibit water penetration via hydrophobic films [29], while internal incorporation is thought to reduce water permeability more persistently [30,31]. Mineral admixtures like cement [8], fly ash [9] react to form ettringite [11,12], enhancing resistance [13,14]. Compactness is improved via water-reducing agents or autoclave curing [32].
Despite substantial research, there is still a lack of comprehensive comparisons regarding the performance and mechanical properties of different waterproofing strategies under short-term versus long-term water absorption conditions. Specifically, the scientific problem lies in understanding how paraffin and VAE emulsions—which operate via distinct mechanisms of pore-filling versus film-forming—interact with the fiber-matrix interface [33]. The mechanisms by which varying emulsion dosages affect the contact angle and micro-structure have yet to be fully elucidated.
In this study, a fiber-reinforced modified gypsum (FRMG) matrix was employed to investigate three approaches: (1) surface coating paraffin emulsion, (2) internal paraffin emulsion, and (3) internal VAE emulsion. The primary goal is to resolve the conflict between moisture sensitivity and mechanical integrity in FRMG. The specific objectives are: (i) to quantify the influence of emulsion types on workability and mechanical properties; (ii) to determine the threshold dosage where waterproofing benefit outweighs mechanical trade-offs; and (iii) to uncover the microstructural evolution of the hydrophobic barrier. This analysis aims to provide an optimized waterproofing strategy to enhance the durability and safety of modern fiber-reinforced gypsum products.

2. Experimental Investigation

2.1. Materials

2.1.1. Gypsum Matrix Materials

In this paper, the gypsum used was the β-hemihydrate gypsum conforming to BS EN 13279-1:2008 standards [34], which was produced by Jiangsu Efful Science and Technology Co., Ltd. (Nanjing, China). The cement utilized in the experiment was ordinary Portland cement P·O 42.5, and its surface area was 397 m2/kg. The fly ash had a thermal conductivity of 0.23 W/(m·K) and a fineness of 335 m2/kg. The lime was calcium oxide (CaO), with a content of at least 98%.
The water/modified gypsum-based matrix ratio employed in this experiment is 0.6, with the modified gypsum-based matrix composed of gypsum, cement, fly ash, and lime in mass proportions of 55%, 10%, 20%, and 15%, respectively [14]. Additionally, to optimize the performance of the gypsum matrix, 0.1% citric acid was incorporated as an additive [35].

2.1.2. Fibers

For this experiment, basalt fibers (BF) were selected for environmentally friendly properties, low energy demand, light weight, high strength, and excellent resistance to corrosion [36,37]. A fiber length of 10 mm and a volume fraction of 1.0% were selected [38]. The density of the fiber is 2.65 g/cm3, the elastic modulus of 93 to 110 MPa, and the fracture elongation of 3.1% [39,40].

2.2. Waterproofing Treatments

In this study, the FRMG matrix was subjected to three distinct treatments: surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of VAE emulsion. The effects of these approaches on the water resistance of the FRMG matrix were systematically evaluated and compared.

2.2.1. Surface Coating with Paraffin Emulsion

The paraffin emulsion was homogeneously blended with water at 20 °C at varying concentrations (0%, 2%, 4%, 6%, and 8%) and vigorously stirred with a glass rod to ensure uniform dispersion. The resulting paraffin solution was then evenly applied to the specimen surface using a brush at a controlled and consistent rate. After each layer had completely dried, the application procedure was repeated twice. The detailed process is schematically illustrated in Figure 1.

2.2.2. Internal Incorporation of Paraffin Emulsion and VAE Emulsion

The paraffin emulsion/VAE emulsion was uniformly mixed with water at 20 °C at varying dosages and thoroughly agitated using a glass stirring rod to ensure homogeneous dispersion. Emulsions with paraffin/VAE concentrations of 0%, 2%, 4%, 6%, and 8% were prepared and subsequently incorporated into the FRMG matrix, which was then cured under standardized conditions. The specific dosage levels of the paraffin emulsion/VAE emulsion are presented and detailed in Figure 2 and Figure 3.

2.3. Factor Level Combinations

The specimens were cured in strict accordance with BS EN 13279–1:2008 [34]. After casting for 24 h, the specimens were maintained at room temperature (20 ± 2 °C) for a curing period of 7 days. Subsequently, they were oven-dried at 40 ± 2 °C until a constant mass was attained, in order to determine their dry-state strength. The types of emulsions employed, methods of incorporation, dosage levels, and corresponding mechanisms are systematically summarized in Table 1.

2.4. Test Procedures

2.4.1. Setting Time

The setting time was determined in accordance with ISO 3051:1974 [41]. The FRMG matrix was cast into a steel mold, subjected to five controlled vibrations, and leveled using a scraper (Figure 4). A needle was released onto the surface at 30-s intervals. The initial setting time was identified when the needle ceased to contact the glass plate, whereas the final setting time was recorded when the penetration depth was less than 1 mm. The average of two measurements, accurate to 1 s, was adopted as the final value. In this study, the initial setting time was selected as the primary parameter for comparing different waterproofing treatments.

2.4.2. Fluidity

The fluidity was determined in accordance with ISO 3051:1974 [41] and measured using the apparatus illustrated in Figure 5, with a target spread of not less than 180 mm. The glass plate was positioned horizontally and pre-moistened, together with the inner wall of the fluidity cylinder. The cylinder was centrally placed on the plate, filled with fresh paste, and subjected to 20 controlled vibrations. It was then vertically lifted by 15 ± 2 mm and maintained in position for 10 s. After the paste had ceased flowing, the spread diameters in two perpendicular directions were measured, and their average value, accurate to 1 mm, was taken as the final result.

2.4.3. Water Absorption

Specimens with dimensions of 40 × 40 × 160 mm3 were prepared for property evaluation. Water absorption was determined in accordance with JC/T 698-2010 [42]. After oven-drying at 40 ± 2 °C for 24 h, the dry mass m was recorded. The specimens were then immersed in water at 20 ± 2 °C for 2 h or 24 h (Figure 6). Subsequently, they were removed, surface moisture was carefully wiped off, and the saturated mass m ’ was recorded. Water absorption was calculated using Equation (1).
ω = m ’ − m m × 100 %
where ω represents the water absorption rate (%); m is the specimen’s dry weight (g); and m ’ is the specimen’s saturated weight (g).

2.4.4. Flexural and Compressive Strength

Flexural and compressive strengths were determined in accordance with ISO 3051:1974 [41] and EN 13279-2:2014 [43]. The loading rates were maintained at 0.03 MPa/s for flexural testing and 0.05 MPa/s for compressive testing. Following the flexural test, the remaining halves of each specimen were utilized for compressive strength measurement. The reported results represent the average of three independent tests, with an accuracy of 0.05 MPa. Flexural and compressive strengths were calculated using Equation (2) and Equation (3), respectively.
R f = 1.5 F f L / b 3
where R f is the flexural strength (MPa), F f is the fracture load (N), L is the span between supports (100 mm), and b the side length of the square cross-section (40 mm).
R c = P / S = P / b 2
where R c is the compressive strength (MPa), P is the maximum compressive load (N), and S is the loading area of the specimen (mm2).

2.4.5. Contact Angle Test

The experiment was conducted using a Dataphysics OCA 15EC contact angle measurement system manufactured in Germany. The instrument features a measurement range of 0–180°, with a precision of ±0.1° and a resolution of ±0.01°. The surface and interfacial tension can be measured within a range of 1 × 10−2 to 2 × 103 mN/m, with a resolution of ±0.01 mN/m. The field of view ranges from 1.05 × 0.66 mm2 to 6.72 × 4.25 mm2. The testing apparatus is schematically illustrated in Figure 7.

3. Results and Discussion

3.1. Setting Time

Figure 8 illustrates the effects of three waterproofing treatments—surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of VAE emulsion—on the setting time. Figure 8a presents a comparative analysis of setting times under different waterproofing treatments, where no significant alterations in the setting-time behavior of the specimens were observed.
As shown in Figure 8b, compared with the control group, the surface coating with paraffin emulsion exhibited no discernible influence on the setting time. However, when paraffin emulsion was internally incorporated into the FRMG matrix, the setting time increased progressively with increasing dosage. Specifically, the addition of 8% paraffin emulsion resulted in a 40.08% increase in setting time compared to the control group. Similarly, the internal incorporation of VAE emulsion also led to a gradual extension of the setting time with increasing dosage, although the magnitude of this effect was comparatively lower than that observed for paraffin emulsion. At an 8% VAE dosage, the setting time increased by 36.95%.
This phenomenon can be attributed to the distinct roles played by different waterproofing treatments during the hydration process of the FRMG matrix. The surface coating with paraffin emulsion is applied post-fabrication and therefore does not participate in the hydration reaction of the matrix [44]. In contrast, the internally incorporated paraffin emulsion is integrated into the gypsum matrix, where it forms a hydrophobic film on the surface of gypsum particles, thereby retarding the hydration process [45]. Similarly, when the VAE emulsion is internally incorporated, an organic polymer film is formed on the surface of gypsum particles and distributed within interparticle voids, which also delays the hydration process to a certain extent [46].

3.2. Fluidity

Figure 9 illustrates the influence of three waterproofing treatments—surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of VAE emulsion—on fluidity variation. As shown in Figure 9a, the surface coating with paraffin emulsion exhibited no discernible effect on fluidity. However, the internal incorporation of 8% paraffin emulsion (II-PE-8%) resulted in a slight reduction, with the spread decreasing from 198 mm to 182 mm. In contrast, the incorporation of 8% VAE emulsion (II-VAE-8%) led to a more pronounced decline, with the fluidity sharply decreasing to 136 mm.
As shown in Figure 9b, the surface coating with paraffin emulsion had no measurable influence on fluidity. However, when paraffin emulsion was internally incorporated, the spread diameter decreased progressively with increasing emulsion content [47]. Compared with the control group, when the dosage reached 8% (II-PE-8%), the extension decreased by 7.97%. In contrast, the incorporation of VAE emulsion resulted in a significantly greater reduction in extension with increasing dosage [48]. This behavior can be attributed to the viscous and polymeric characteristics of VAE emulsion, which reduced the flowability of the gypsum matrix [48]. When 8% VAE emulsion was internally incorporated (II-VAE-8%), the spreadability decreased by 31.4% compared with the control group.

3.3. Water Absorption

Figure 10 presents the variation in water absorption after 24 h of immersion under different waterproofing treatments. The control group exhibited a water absorption rate of approximately 30%, whereas the values for the SC-PE-8%, II-PE-8%, and II-VAE-8% groups were reduced to 23.4%, 11.85%, and 16.9%, respectively. These results demonstrated that all three waterproofing treatments effectively decreased water absorption in gypsum specimens. Among them, the internal incorporation of paraffin emulsion yielded the lowest water uptake, followed by the internal incorporation of VAE emulsion, and subsequently the surface-coated paraffin emulsion. The underlying mechanisms responsible for these differences are further elucidated in the subsequent sections.
Figure 11 illustrates the effects of different waterproofing treatments on the water absorption behavior of the FRMG matrix. The results indicated that during the 2 h immersion test, the water absorption rate of the FRMG matrix decreased progressively with increasing dosages of surface-coated paraffin emulsion, internally incorporated paraffin emulsion, and VAE emulsion. However, in the 24 h immersion test, the surface coating with paraffin emulsion did not result in a significant reduction in water absorption. In contrast, the internal incorporation of paraffin emulsion led to a pronounced decrease in water absorption with increasing dosage, whereas the reduction observed for VAE emulsion was comparatively more moderate than that of paraffin emulsion.
The primary reason for this phenomenon can be attributed to the time-dependent effectiveness of different waterproofing mechanisms. In the short term, surface coating with paraffin emulsion provided superior waterproofing performance compared to internally incorporated paraffin and VAE emulsions. However, its effectiveness gradually deteriorated over time. After 24 h of immersion, the waterproof film formed by the surface-coated paraffin emulsion on the gypsum specimen surface was compromised, thereby allowing moisture to penetrate into the FRMG matrix, resulting in water absorption levels approaching those of the untreated control group [49]. In contrast, both internally incorporated paraffin and VAE emulsions formed hydrophobic films on the surfaces of gypsum crystals, which maintained a more stable and effective waterproofing performance even after prolonged immersion [50].

3.4. Flexural Strength

Figure 12 illustrates the effects of different waterproofing treatments on the variation in flexural strength. As shown in Figure 12A, compared with the control group, the failure modes in the flexural strength tests were minimally influenced by the different waterproofing treatments, with ductile failure being observed in all cases. Under loading, cracks were initiated at the bottom of the specimens and propagated upward. Owing to the random distribution of fibers within the FRMG matrix and the “bridging effect”, further crack propagation was effectively restrained [51].
As depicted in Figure 12B, the surface coating with paraffin emulsion exerted no significant influence on flexural strength. In contrast, with the internal incorporation of paraffin emulsion, flexural strength decreased progressively with increasing dosage. At an 8% dosage (II-PE-8%), flexural strength decreased by 8.90% compared with the control group, indicating a statistically significant reduction. Conversely, the incorporation of VAE emulsion resulted in a nonlinear trend, with flexural strength initially increasing and subsequently decreasing as the dosage increased. The maximum strength was attained at a 6% dosage, representing a 10.36% enhancement relative to the control group.
This phenomenon can be attributed to the distinct interaction mechanisms of the materials. The surface coating with paraffin emulsion affected only the external surface, leaving the internal microstructure largely unchanged. In contrast, the internal incorporation of paraffin emulsion led to the formation of hydrophobic films on the surfaces of gypsum hydration products [52]. Although higher dosages enhanced water resistance, they simultaneously weakened the intercrystalline bonding [53]. Meanwhile, the VAE emulsion formed an in situ continuous polymer network within the FRMG matrix, which not only refined the pore structure but also enhanced toughness through improved stress transfer, thereby significantly increasing flexural strength [54].

3.5. Compressive Strength

Figure 13 presents the influence of different waterproofing treatments on compressive strength. As shown in Figure 14a, no significant differences were observed in the compressive failure modes among the various treatments. Due to the “bridging effect” of the fibers, although the specimens were subjected to vertical loading, the formation of lateral cracks was effectively restrained, thereby preventing brittle fracture [55].
As illustrated in Figure 13b, the application of paraffin emulsion as a surface coating exhibited negligible influence on compressive strength. However, when paraffin emulsion was internally incorporated, the compressive strength of the gypsum decreased progressively with increasing dosage. Compared with the control group, the compressive strength decreased by 10.1% at an 8% paraffin emulsion dosage (II-PE-8%). In contrast, the incorporation of VAE emulsion demonstrated a nonlinear variation trend, with compressive strength initially increasing, reaching a peak at a dosage of 6% (II-VAE-6%), and subsequently declining. Compared with the control group, the compressive strength of II-VAE-6% increased by 8.62%.
This phenomenon can be primarily attributed to the behavior of paraffin emulsion when internally incorporated into the FRMG matrix. As the matrix gradually hardened, paraffin microparticles became dispersed within internal voids and along pore surfaces, partially hindering the bonding between gypsum crystals [56]. Under applied loading, this disruption induced localized stress concentrations, ultimately leading to specimen failure [57]. In contrast, the VAE emulsion formed a continuous waterproof membrane within the FRMG matrix, which was distributed throughout the pore structure, thereby reducing porosity and enhancing both waterproofing performance and compressive strength. However, when the VAE content exceeded an optimal threshold, excess organic polymer adhered to the surfaces of gypsum crystals, thereby impeding the formation of cohesive bonds [58,59]. This not only increased the viscosity and porosity of the matrix but also elevated the overall pore volume, ultimately resulting in a reduction in the mechanical strength of the gypsum specimen [6].

3.6. Contact Angle

Figure 14 presents the influence of different waterproofing treatments on the contact angle. As illustrated in Figure 14a, the surface of the control specimen rapidly absorbed water droplets, exhibiting a contact angle of 50.6° (<90°), which indicates a hydrophilic characteristic. In contrast, when the specimen surface was coated with 8% paraffin emulsion (SC-PE-8%), the residence time of water droplets was markedly prolonged, and the contact angle increased to 136.4° (>90°), indicating enhanced hydrophobicity. When 8% paraffin emulsion (II-PE-8%) was internally incorporated, the contact angle reached 155.1° (>90°), demonstrating superior hydrophobic performance compared to surface coating. Furthermore, the specimen incorporating 8% vinyl acetate–ethylene emulsion (II-VAE-8%) also exhibited pronounced hydrophobicity, with a contact angle of 137.1° (>90°) and a significantly extended water droplet retention time.
As shown in Figure 14b, with increasing dosages of surface-coated paraffin emulsion, internally incorporated paraffin emulsion, and internally incorporated VAE emulsion, the contact angle of the gypsum specimen surface gradually transitioned from hydrophilic to hydrophobic behavior. The contact angle increased sharply from 50.6° to values exceeding 90°, and continued to rise with further increases in emulsion content. Moreover, at equivalent dosages, the contact angle corresponding to internally incorporated paraffin emulsion was higher than that of surface-coated paraffin emulsion, indicating that internal modification provided more effective waterproofing than surface treatment [60]. Additionally, at the same dosage level, the contact angle for internally incorporated paraffin emulsion exceeded that of internally incorporated VAE emulsion.

4. Mechanism Analysis

4.1. Waterproofing Mechanism

The three waterproofing treatments employed in this study comprised surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of VAE emulsion. The following section provides a comprehensive elucidation of the underlying waterproofing mechanisms associated with each approach.

4.1.1. Control Group

As shown in Figure 15a, in the control group, gypsum crystals reacted with mineral admixtures such as cement and lime to form ettringite, which filled pores and enhanced the matrix density, thereby imparting a certain degree of waterproofing performance [61]. However, the gypsum matrix contained numerous fibers and capillary structures susceptible to water ingress, allowing moisture to penetrate into the interior and significantly compromise the overall waterproofing capacity [62]. Under humid conditions or prolonged exposure to water, the water resistance of the modified gypsum remained a persistent challenge [29].

4.1.2. Waterproofing Mechanism of Surface Coating with Paraffin Emulsion

As illustrated in Figure 15b, the waterproofing mechanism of the surface coating with paraffin emulsion was primarily governed by the formation of a continuous hydrophobic film on the specimen surface. This film effectively reduced surface wettability, thereby inhibiting direct water penetration [60]. Acting as a primary barrier, the film retarded moisture diffusion, providing a certain degree of waterproofing protection [63]. However, since this mechanism operated solely at the surface level without reinforcing the internal structure, prolonged immersion could lead to coating degradation, resulting in a significant decline in waterproofing performance [64]. Moreover, as the surface coating did not modify the internal structure of the FRMG matrix, it exerted no influence on setting time, fluidity, flexural strength, or compressive strength [65,66].

4.1.3. Waterproofing Mechanism of Internal Incorporation Paraffin Emulsion

As shown in Figure 15c, the waterproofing mechanism of the internally incorporated paraffin emulsion was primarily attributed to the uniform dispersion of fine paraffin particles throughout the gypsum matrix during the hydration process. These particles formed a stable internal hydrophobic barrier, which disrupted continuous capillary pathways for water ingress, thereby effectively reducing water absorption [52]. Compared with surface-coated paraffin emulsion, the internally incorporated paraffin emulsion provided a more durable and resilient protective effect; even when the surface layer was compromised, the material retained a certain degree of impermeability, thereby significantly enhancing the water resistance of the gypsum matrix [67,68].

4.1.4. Waterproofing Mechanism of Internal Incorporation VAE Emulsion

As shown in Figure 16d, the internal incorporation of VAE emulsion resulted in the formation of continuous polymer films during the hydration process of gypsum. These films filled and sealed the interstitial voids between gypsum crystals, thereby effectively blocking micropores and microcracks. Consequently, a denser microstructure was achieved, and the migration of moisture through the material was significantly impeded, functioning as an effective physical barrier [56,69]. Furthermore, the presence of the polymer enhanced the structural integrity and flexibility of the matrix, thereby mitigating microcrack formation induced by swelling and wet–dry cycles, and consequently improving the overall water resistance [58,59].

4.2. Microscopic Structure

By integrating experimental data with scanning electron microscopy (SEM) observations, the internal structural evolution of the gypsum matrix under various waterproofing treatments was systematically elucidated. As the application of surface coating with paraffin emulsion did not induce significant alterations within the matrix, the SEM analysis presented in this section was confined to the control group and specimens with internally incorporated paraffin emulsion and VAE emulsion.

4.2.1. Internal Incorporation Paraffin Emulsion

To investigate the evolving effects of internally incorporated paraffin emulsion on the internal structure of the FRMG matrix, paraffin emulsion was introduced into the gypsum matrix at dosages of 2%, 4%, 6%, and 8%, followed by microstructural characterization and analysis using scanning electron microscopy (SEM). Figure 16 illustrates the microscopic morphology of the gypsum composite matrices with varying dosages of internally incorporated paraffin emulsion at a magnification of 4000×.
As shown in Figure 16, in the control group, the FRMG matrix exhibited gypsum crystals, ettringite, and a substantial degree of internal porosity [61]. However, with increasing dosages of internally incorporated paraffin emulsion, the surfaces of the gypsum crystals became progressively coated with paraffin particles, which effectively filled the intercrystalline voids and reduced overall porosity [45]. Upon incorporation of paraffin emulsion (Figure 16b–e), the emulsion adhered to pore surfaces and gypsum crystal interfaces, resulting in a contact angle exceeding 90°, indicative of strong hydrophobicity [49]. Furthermore, this hydrophobic effect became more pronounced with increasing paraffin content. Consequently, after water immersion, the gypsum specimens demonstrated a significant improvement in both compressive and flexural softening coefficients.

4.2.2. Internal Incorporation VAE Emulsion

To investigate the evolving influence of internally incorporated VAE emulsion on the microstructure of the FRMG matrix, VAE emulsion was introduced at dosages of 2%, 4%, 6%, and 8%, respectively. The resulting internal structural variations were examined and analyzed using scanning electron microscopy (SEM). Figure 17 illustrates the effects of varying VAE emulsion dosages on the internal structure of the FRMG matrix at a magnification of 4000×.
As depicted in Figure 17, in the control group, where no waterproofing treatment was applied, the crystals primarily exhibited plate-like and rhombohedral morphologies [70]. Despite being partially encapsulated by mineral phases such as ettringite, the intercrystalline voids remained relatively large [17]. However, upon the incorporation of VAE emulsion—as shown in Figure 17b–e the morphology of gypsum crystals transformed into rod-like, flaky, and prismatic structures [71]. With increasing VAE emulsion content, the crystal surfaces became progressively coated with a waterproof polymeric film, thereby enhancing intercrystalline bonding. A distinct polymer membrane was observed enveloping the crystal surfaces [72]. The synergistic effect of physical coating and chemical compatibility between the emulsions and the gypsum-based matrix has been confirmed through FTIR and XRD analyses [73].
The enhancement in waterproofing performance was primarily attributed to the formation of a continuous polymeric membrane during the curing process [74]. These membranes filled and sealed the intercrystalline voids, resulting in a denser microstructure, which significantly impeded moisture migration within the material, reduced porosity, and improved overall compactness [58,59]. This densification effect ultimately led to a substantial improvement in the waterproofing capability of the FRMG matrix.

5. Conclusions

This study systematically investigated the effects of surface coating with paraffin emulsion, internally mixed paraffin emulsion, and VAE emulsion on the performance of FRMG matrix specimens. A comparative analysis was conducted to examine the effects of various waterproofing treatments on the contact angle and the microstructural evolution of the FRMG matrix. The key conclusions are as follows:
(1)
Surface coating with paraffin emulsion exerted negligible influence on the fundamental properties of the FRMG matrix, while providing effective short-term hydrophobicity. However, the waterproofing performance deteriorated significantly after prolonged immersion due to degradation of the surface hydrophobic film.
(2)
Internal incorporation of paraffin emulsion formed a stable hydrophobic barrier that effectively reduced water absorption, but led to delayed setting and a reduction in mechanical strength, with both compressive and flexural strength decreasing progressively as dosage increased.
(3)
Internal incorporation of VAE emulsion generated continuous polymer films that filled pores and sealed microcracks, significantly enhancing waterproofing performance. Meanwhile, mechanical properties exhibited a nonlinear response, with optimal strength achieved at 6% dosage. Overall, internal modification strategies (paraffin and VAE) improved hydrophobicity and provided more durable waterproofing compared to surface treatment.
(4)
Increasing the dosage of paraffin (surface and internal) and VAE emulsion consistently enhanced the contact angle, indicating improved hydrophobicity. Compared with surface treatment, internal modification provided more durable and stable waterproofing performance.
(5)
While this study provides a foundational framework for FRMG, future research should prioritize elucidating the multi-scale interfacial mechanisms and long-term durability under service-relevant conditions to refine application boundaries and optimize hybrid modification strategies for specific indoor and outdoor environments.

Author Contributions

Z.L. (Zhenxing Li): conceptualization, methodology, investigation, writing—original draft, review. S.R.: editing, and visualization. D.L. (Dongning Li): conceptualization, methodology. D.L. (Dejing Lu): investigation, visualization. H.Z.: investigation, visualization. C.L.: conceptualization, editing. J.S.: conceptualization, editing. Z.L. (Zuohua Li): supervision, resources, and funding acquisition. X.W.: supervision, review. All authors have read and agreed to the published version of the manuscript.

Funding

The authors gratefully acknowledge the financial support provided by the Shenzhen Collaborative Innovation Project (Grant No. CJGJZD20220517142401002), Shenzhen Construction Technology Research and Development Projects (SZKJXM20250100), China Scholarship Council (Grant Numbers CSC 202106090114), National Key Research and Development Program of China (No. 2023YFC3806604).

Data Availability Statement

All data, models, and codes generated or used during the study appear in the submitted article.

Conflicts of Interest

Authors Zhenxing Li, Shaohua Rao, Dongning Li, Dejing Lu and Huaitao Zhu were employed by the company Shenzhen Public Housing Group Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

  1. Guan, Q.; Sui, Y.; Zhang, F.; Yu, W.; Bo, Y.; Wang, P.; Peng, W.; Jin, J. Preparation of α-calcium sulfate hemihydrate from industrial by-product gypsum: A review. Physicochem. Probl. Miner. Process. 2021, 57, 168–181. [Google Scholar] [CrossRef]
  2. Wang, S.; Pancheti, J.; Xi, Y.; Mahendran, M. Lightweight composite gypsum boards with clay mineral and glass fibre for enhanced fire-resistance. Compos. Part B Eng. 2023, 266, 111044. [Google Scholar] [CrossRef]
  3. Singh, S.; Maiti, S.; Bisht, R.S.; Balam, N.B.; Solanki, R.; Chourasia, A.; Panigrahi, S.K. Performance behaviour of agro-waste based gypsum hollow blocks for partition walls. Sci. Rep. 2022, 12, 3204. [Google Scholar] [CrossRef]
  4. Maiti, S.; Jain, N.; Malik, J. Light Weight Plasters Containing Vermiculite and FGD Gypsum Wastes for Sustainable and Energy Efficient Building Construction Material. J. Inst. Eng. (India) Ser. A 2023, 104, 603–614. [Google Scholar]
  5. Abu-Ennab, L.; Dixit, M.; Birgisson, B.; Kumar, P.P. Comparative life cycle assessment of large-scale 3D printing utilizing kaolinite-based calcium sulfoaluminate cement concrete and conventional construction. Clean. Environ. Syst. 2022, 5, 100078. [Google Scholar]
  6. Esan, M.T. Review of gypsum reinforced composites as building materials. Discov. Civ. Eng. 2024, 1, 5. [Google Scholar] [CrossRef]
  7. Li, X.; Zhu, L.; Liu, J.; Cao, Z.; Xue, Y.; Dang, F. Fracture evolution and mechanical deterioration of granite under cyclic thermal and liquid nitrogen cryogenic impact. Phys. Fluids 2025, 37, 086652. [Google Scholar] [CrossRef]
  8. Lesovik, V.; Chernysheva, N.; Fediuk, R.; Amran, M.; Murali, G.; de Azevedo, A.R. Optimization of fresh properties and durability of the green gypsum-cement paste. Constr. Build. Mater. 2021, 287, 123035. [Google Scholar] [CrossRef]
  9. Pietrzak, A.; Ulewicz, M.; Kozień, E.; Pietraszek, J. Application of a Mixture of Fly Ash and Solid Waste from Gas Treatment from Municipal Solid Waste Incineration in Cement Mortar. Materials 2025, 18, 481. [Google Scholar] [CrossRef]
  10. Elert, K.; Alaminos, R.A.; Benavides-Reyes, C.; Burgos-Ruiz, M. The effect of lime addition on weathering resistance and mechanical strength of gypsum plasters and renders. Cem. Concr. Compos. 2023, 139, 105012. [Google Scholar] [CrossRef]
  11. Zormati, S.; Aloulou, F.; Sammouda, H. Effects of cationic surfactant on fresh and hardened properties of cement-based mortar. J. Renew. Mater. 2023, 11, 2345. [Google Scholar] [CrossRef]
  12. Laatiri, Y.; Sammouda, H.; Aloulou, F. Bio-PCM Panels Composed of Renewable Materials Interact with Solar Heating Systems for Building Thermal Insulation. J. Renew. Mater. 2024, 12, 771–798. [Google Scholar] [CrossRef]
  13. Zhang, Y.; Dong, M.; Zhang, W.; Chen, H.; Yang, D. Preparation of mineral admixture from iron tailings with steel slag-desulfurization ash and its application to concrete. Materials 2022, 15, 5162. [Google Scholar] [CrossRef] [PubMed]
  14. Li, Z.; Wang, X.; Hou, Y.; Wu, Z. Optimization of mechanical properties and water absorption behavior of building gypsum by ternary matrix mixture. Constr. Build. Mater. 2022, 350, 128910. [Google Scholar] [CrossRef]
  15. Li, Z.; Wang, X.; Zhu, Z.; Wu, Z. Effect of mixing methods on the dispersion of fibers in the gypsum matrix and performance improvement mechanism. Constr. Build. Mater. 2022, 320, 126193. [Google Scholar] [CrossRef]
  16. Aloulou, F.; Alila, S. Effect of modified fibre flour wood on the fresh condition properties of cement-based mortars. Int. J. Mason. Res. Innov. 2019, 4, 355–377. [Google Scholar] [CrossRef]
  17. Yuan, J.; Guo, L.; Chen, S.; Liu, Y.; Feng, Y.; Lu, H. Solidified lake sediment with industrial waste and construction waste used as barrier cover material: Mechanical strength, water resistance performance, and microscopic analysis. Environ. Technol. 2025, 46, 3090–3106. [Google Scholar] [CrossRef]
  18. Ponduru, S.A.; Aylas-Paredes, B.K.; Han, T.; Neithalath, A.; Neithalath, N.; Sant, G.; Kumar, A. Effects of Gypsum and Limestone on Early-Age Hydration and Strength Optimization in Belite Calcium Sulfoaluminate Cement. Infrastructures 2025, 10, 27. [Google Scholar] [CrossRef]
  19. Yuan, Z.; Jia, Y.; Xie, X.; Xu, J. Study on the Macroscopic Properties and Microstructure of High Fly Ash Content Alkali-Activated Fly Ash Slag Concrete Cured at Room Temperature. Materials 2025, 18, 547. [Google Scholar] [CrossRef]
  20. Durgun, M.Y. Effect of wetting-drying cycles on gypsum plasters containing ground basaltic pumice and polypropylene fibers. J. Build. Eng. 2020, 32, 101801. [Google Scholar] [CrossRef]
  21. Feng, C.; Wang, Y.; Wang, L.; Zhao, X.; Zhang, W.; Zhu, J.; Du, M. Improving the water resistance of gypsum-based building materials with slag activated by calcium oxide. J. CO2 Util. 2024, 90, 102996. [Google Scholar] [CrossRef]
  22. Jiang, C.; Fan, K.; Wu, F.; Chen, D. Experimental study on the mechanical properties and microstructure of chopped basalt fibre reinforced concrete. Mater. Des. 2014, 58, 187–193. [Google Scholar] [CrossRef]
  23. Zhang, Z.; Sun, W.; Huang, W.; Zhu, Y.; Li, J.; Liang, C.; Gao, S. Interfacial and mechanical properties of silane coupling agent interface-modified basalt fiber reinforced thermoplastic polypropylene resin composites. Polym. Compos. 2025, 46, 6582–6593. [Google Scholar] [CrossRef]
  24. Elhadary, R.; Bassuoni, M. Interfacial bonding between basalt fiber/polymer pellets and various nano-modified cementitious matrices. J. Mater. Civ. Eng. 2023, 35, 04022471. [Google Scholar] [CrossRef]
  25. Kim, J.-K.; Mai, Y.-W. Engineered Interfaces in Fiber Reinforced Composites; Elsevier: Amsterdam, The Netherlands, 1998. [Google Scholar]
  26. Yoo, D.Y.; Banthia, N. Mechanical properties of ultra-high-performance fiber-reinforced concrete: A review. Cem. Concr. Compos. 2016, 73, 267–280. [Google Scholar] [CrossRef]
  27. Liu, S.; Liu, W.; Jiao, F.; Qin, W.; Yang, C. Production and resource utilization of flue gas desulfurized gypsum in China-A review. Environ. Pollut. 2021, 288, 117799. [Google Scholar] [CrossRef]
  28. Jia, R.; Wang, Q.; Feng, P. A comprehensive overview of fibre-reinforced gypsum-based composites (FRGCs) in the construction field. Compos. Part B Eng. 2021, 205, 108540. [Google Scholar] [CrossRef]
  29. Wang, L.; Cao, M.; Li, X.; Du, W.; Wang, X. A novel approach for improving the water resistance of gypsum plaster by internal mixing hypromellose and external coating waterproofing agent. Constr. Build. Mater. 2023, 401, 132940. [Google Scholar] [CrossRef]
  30. Akeed, M.H.; Qaidi, S.; Faraj, R.H.; Mohammed, A.S.; Emad, W.; Tayeh, B.A.; Azevedo, A.R. Ultra-high-performance fiber-reinforced concrete. Part II: Hydration and microstructure. Case Stud. Constr. Mater. 2022, 17, e01289. [Google Scholar] [CrossRef]
  31. Yao, H.; Xie, Z.; Huang, C.; Yuan, Q.; Yu, Z. Recent progress of hydrophobic cement-based materials: Preparation, characterization and properties. Constr. Build. Mater. 2021, 299, 124255. [Google Scholar] [CrossRef]
  32. del Río-Merino, M.; Vidales-Barriguete, A.; Piña-Ramírez, C.; Vitiello, V.; Santa Cruz-Astorqui, J.; Castelluccio, R. A review of the research about gypsum mortars with waste aggregates. J. Build. Eng. 2022, 45, 103338. [Google Scholar] [CrossRef]
  33. Najduchowska, M.; Pichniarczyk, P. Effect of hydrophobic agents on the properties of cement and gypsum mortars. Cem. Wapno Beton 2008, 15, 141–148. [Google Scholar]
  34. EN B. 13279-1: 2008; Gypsum Binders and Gypsum Plasters; Part 1: Definitions and Requirements. British Standards: London, UK, 2008.
  35. Li, Z.; Wang, X.; Wijeyewickrema, A.C.; Wu, Z. Flexural performance enhancement of modified gypsum-based composite boards using basalt fiber braids. Constr. Build. Mater. 2024, 418, 135430. [Google Scholar] [CrossRef]
  36. Pareek, K.; Saha, P. Basalt Fiber and Its Composites: An Overview. In Proceedings of the National Conference on Advances in Structural Technologies; Springer: Singapore, 2019. [Google Scholar]
  37. Ding, L.; Liu, Y.; Liu, J.; Wang, X. Correlation analysis of tensile strength and chemical composition of basalt fiber roving. Polym Compos. 2019, 40, 2959–2966. [Google Scholar] [CrossRef]
  38. Li, Z.; Wang, X.; Yan, W.; Ding, L.; Liu, J.; Wu, Z.; Huang, H. Physical and mechanical properties of gypsum-based composites reinforced with basalt, glass, and PVA fibers. J. Build. Eng. 2023, 64, 105640. [Google Scholar] [CrossRef]
  39. Wu, Z.; Wang, X.; Wu, G. Advancement of structural safety and sustainability with basalt fiber reinforced polymers. In Proceedings of the 6th International Conference on FRP Composites in Civil Engineering, CICE 2012, Rome, Italy, 13–15 June 2012; Volume 13, pp. 15–29. [Google Scholar]
  40. Sun, X.; Gao, Z.; Cao, P.; Zhou, C. Mechanical properties tests and multiscale numerical simulations for basalt fiber reinforced concrete. Constr. Build. Mater. 2019, 202, 58–72. [Google Scholar] [CrossRef]
  41. ISO 3051:1974; Gypsum Plasters—Determination of Mechanical Properties. International Organization for Standardization: Geneva, Switzerland, 1974.
  42. JC/T 698-2010; Gypsum Blocks. China National Light Industry Council: Beijing, China, 2010.
  43. EN 13279-2:2014; Gypsum Binders and Gypsum Plasters—Part 2: Test Methods. CEN: Brussels, Belgium, 2014.
  44. Huo, J.; Wang, Z.; Zhang, T.; He, R.; Chen, H. Influences of interaction between cement and ionic paraffin emulsion on cement hydration. Constr. Build. Mater. 2021, 299, 123951. [Google Scholar] [CrossRef]
  45. Cao, J.-Y.; Li, J.-P.; Jiang, Y.-M.; Wang, S.-L.; Ding, Y.; Oh, W.-C. Improvement in water resistance of desulfurized gypsum by novel modification of silicone oil paraffin composite emulsion-based waterproofing agent. J. Korean Ceram. Soc. 2019, 56, 558–565. [Google Scholar] [CrossRef]
  46. Ma, H.; Wang, R.; Xi, Z.; Gao, H.; Fryda, H.; Wang, P. Regulation and inhibition of early whitening of calcium aluminate cement/hemihydrate gypsum decorative mortar by polymer emulsion. Constr. Build. Mater. 2023, 393, 132023. [Google Scholar] [CrossRef]
  47. Khadkekar, S.A.; Kareti, M.R.; Yelishetty, M.S.; Aditya, S.V.; Daripalli, S. Incorporation of opacifier to Type III alpha gypsum and its effect on scannability and linear setting expansion—An in vitro study. J. Indian Prosthodont. Soc. 2025, 25, 80–85. [Google Scholar] [CrossRef]
  48. Zhang, P.; Yang, A.; Wang, X.; Wang, L.; Sha, Y.; Li, M. Synergistic Effects of Biogas Slurry as a Nitrogen Substitute Under Different Straw Incorporation Methods on Soybean Yield and Emission Reduction. Available online: https://www.researchgate.net/publication/387770120_Synergistic_Effects_of_Biogas_Slurry_as_a_Nitrogen_Substitute_Under_Different_Straw_Incorporation_Methods_on_Soybean_Yield_and_Emission_Reduction (accessed on 2 March 2026).
  49. Li, J.; Cao, J.; Ren, Q.; Ding, Y.; Zhu, H.; Xiong, C.; Chen, R. Effect of nano-silica and silicone oil paraffin emulsion composite waterproofing agent on the water resistance of flue gas desulfurization gypsum. Constr. Build. Mater. 2021, 287, 123055. [Google Scholar] [CrossRef]
  50. Wang, F.F.; Li, G.Z.; Liu, M.R. Effect of waterproof emulsion on properties of calcined gypsum from flue gas desulfurization. Adv. Mater. Res. 2011, 168, 478–481. [Google Scholar]
  51. Le, L.A.; Nguyen, G.D.; Bui, H.H.; Sheikh, A.H.; Kotousov, A. Incorporation of micro-cracking and fibre bridging mechanisms in constitutive modelling of fibre reinforced concrete. J. Mech. Phys. Solids 2019, 133, 103732. [Google Scholar] [CrossRef]
  52. Al-Dulaimi, S.D.S.; Bazhenova, S.; Stepina, I.; Erofeeva, I.; Afonin, V. Development of efficient compositions of hydrophobic materials resistant to chemical and biological environments. J. Infrastruct. Preserv. Resil. 2024, 5, 18. [Google Scholar] [CrossRef]
  53. Jiang, M.; Zheng, K.; Yao, H.; Prateek, G. Effect of paraffin oil nanoemulsion as a hydrophobic modifier on cement paste workability and hydration. J. Mater. Civ. Eng. 2024, 36, 04024029. [Google Scholar] [CrossRef]
  54. Bai, E.; Liu, G.; Xu, J.; Yang, N.; Wen, C. Tensile properties of a flexible polymer-cement composite containing portland cement and vae emulsion. Ceram. Silik. 2019, 64, 92–99. [Google Scholar] [CrossRef]
  55. Brighenti, R.; Carpinteri, A.; Spagnoli, A.; Scorza, D. Crack Paths in Unidirectional Fibre-Reinforced Brittle-Matrix Materials through Two Computational Models. sign 2012, 2, 1. [Google Scholar]
  56. Shagymgereyeva, S.; Sarsenbekuly, B.; Kang, W.; Turtabayev, S. Performance Evaluation of Fluorescent Polymer Gel Microspheres as a Reservoir Conformance Control Agent. Gels 2025, 11, 85. [Google Scholar] [CrossRef]
  57. Ahmed, W.; Zaneldin, E.; El Hassan, A. Investigating the Integrity and Failure Characteristics of Deteriorated Polymeric 3D-Printed Components as Candidates for Structural and Construction Applications. Buildings 2023, 13, 2402. [Google Scholar] [CrossRef]
  58. Fu, H.; Pang, B.; Wang, P.; Yang, C.; Liu, Y.; Du, Z.; Ji, H. Microstructure and durability of rapid repair mortar with self-emulsifying waterborne epoxy polymer. Mater. Today Commun. 2024, 40, 109375. [Google Scholar] [CrossRef]
  59. Toan, M.; Choi, J.; Ngo, H.T.; Bae, J.-Y.; Shin, S.; Kwon, K. Synthesis of novel zwitterionic surfactants: Achieving enhanced water resistance and adhesion in emulsion polymer adhesives. Polymers 2024, 16, 3504. [Google Scholar] [CrossRef]
  60. Junge, F.; Haag, R. Effect of Fluorophilic-and Hydrophobic-Modified Polyglycerol-Based Coatings on the Wettability of Low Surface Energy Polymers. Langmuir 2025, 41, 3305–3314. [Google Scholar]
  61. Abdolvand, Y.; Sadeghiamirshahidi, M. Soil stabilization with gypsum: A review. J. Rock Mech. Geotech. Eng. 2024, 16, 5278–5296. [Google Scholar] [CrossRef]
  62. Vidales-Barriguete, A.; Atanes-Sanchez, E.; del Rio-Merino, M.; Pina-Ramirez, C. Analysis of the improved water-resistant properties of plaster compounds with the addition of plastic waste. Constr. Build. Mater. 2020, 230, 116956. [Google Scholar] [CrossRef]
  63. Choi, J.-S.; Woo, B.-H.; Kim, H.-G.; Kim, J.-Y.; Ryou, J.-S. Possibility investigation of phase change material-impregnated and surface coated cork as an aggregate for building envelope application. Adv. Build. Energy Res. 2025, 19, 241–267. [Google Scholar] [CrossRef]
  64. Cao, G.; Zhao, W.; Han, L.; Teng, Y.; Xu, S.; Nguyen, H.; Tam, K.C. Enhancing Droplet Spreading on a Hydrophobic Plant Surface by Surfactant/Cellulose Nanocrystal Complexes. ACS Nano 2025, 19, 3549–3561. [Google Scholar] [CrossRef] [PubMed]
  65. Zhou, Y.G.; Liang, T.F.; Wu, B.Y. Effect of surface treatment on interfacial shear strength of basalt fiber reinforced polypropylene composite. Polym. Compos. 2025, 46, 8408–8423. [Google Scholar] [CrossRef]
  66. Bakar, N.H.A.; Kabeb, S.M. Effect of Tribology on Multifunctional Coating Surface/Interface. In Multi-Scale and Multifunctional Coatings and Interfaces for Tribological Contacts; CRC Press: Boca Raton, FL, USA, 2025; pp. 30–43. [Google Scholar]
  67. Zaragoza-Benzal, A.; Ferrández, D.; Barrios, A.M.; Morón, C. Water Resistance Analysis of New Lightweight Gypsum-Based Composites Incorporating Municipal Solid Waste. J. Compos. Sci. 2024, 8, 393. [Google Scholar] [CrossRef]
  68. Bozorgi, S.J.; Sajjadei, N.; Hashemi, M.; Kharkeshi, M.M. Polyethylene glycol plus paraffin vs. Polyethylene glycol alone: Which is more effective in treating pediatric functional constipation? A Randomized controlled clinical trial. Res. Sq. 2024. preprint. [Google Scholar]
  69. Li, Z.; Zhang, L.; Shan, Y.; Zhao, Y.; Dai, L.; Wang, Y.; Sun, Q.; McClements, D.J.; Cheng, Y.; Xu, X. Fabrication of high internal phase emulsions (HIPEs) using pea protein isolate-hyaluronic acid-tannic acid complexes: Application of curcumin-loaded HIPEs as edible inks for 3D food printing. Food Chem. 2024, 460, 140402. [Google Scholar] [CrossRef]
  70. Putnis, C.V.; Wang, L.; Ruiz-Agudo, E.; Ruiz-Agudo, C.; Renard, F. Crystallization via nonclassical pathways: Nanoscale imaging of mineral surfaces. In Crystallization via Nonclassical Pathways Volume 2: Aggregation, Biomineralization, Imaging & Application; ACS Publications: Washington, DC, USA, 2021; pp. 1–35. [Google Scholar]
  71. Liu, Z.; Jiang, J.; Liu, G.; Shi, J.; Wang, Y.; Wang, F.; Zhang, Y. Ethylene Vinyl Acetate Copolymer Emulsion-Modified Alkali-Activated Slag Repair Material: Mechanical Strength and Durability Linked to Microstructural Properties. J. Mater. Civ. Eng. 2024, 36, 04024175. [Google Scholar] [CrossRef]
  72. Wei, S.; Huang, S.; Zhou, J.; Xiao, C.; Cao, J.; Xiao, J.; Xie, C. Magnetic Carbon Porous Polymer Prepared from a New Suspended Emulsion for the Absorption of Heavy Metal Ions. Polymers 2025, 17, 257. [Google Scholar] [CrossRef] [PubMed]
  73. Luo, X.; Gao, J.; Liu, C.; He, Z. Effects of Polymers on Workability and Early Microstructure of Gypsum-Based Materials. ACI Mater. J. 2021, 118, 29. [Google Scholar] [CrossRef]
  74. Zhang, F.; Guo, H.; Wang, W.; Du, J.; Liu, Y.; Wang, H. Fast prediction of curing residual stress in polymer-matrix composites by a deep learning method. Polym. Compos. 2025, 46, 8424–8441. [Google Scholar]
Buildings 16 01491 g001
Figure 1. Paraffin emulsion surface coating process.
Figure 1. Paraffin emulsion surface coating process.
Buildings 16 01491 g001
Buildings 16 01491 g002
Figure 2. Different concentrations of paraffin emulsion.
Figure 2. Different concentrations of paraffin emulsion.
Buildings 16 01491 g002
Buildings 16 01491 g003
Figure 3. Different concentrations of VAE emulsion.
Figure 3. Different concentrations of VAE emulsion.
Buildings 16 01491 g003
Buildings 16 01491 g004
Figure 4. Setting time devices.
Figure 4. Setting time devices.
Buildings 16 01491 g004
Buildings 16 01491 g005
Figure 5. Fluidity testing devices.
Figure 5. Fluidity testing devices.
Buildings 16 01491 g005
Buildings 16 01491 g006
Figure 6. Water absorption test device.
Figure 6. Water absorption test device.
Buildings 16 01491 g006
Buildings 16 01491 g007
Figure 7. Contact angle treatment instrument.
Figure 7. Contact angle treatment instrument.
Buildings 16 01491 g007
Buildings 16 01491 g008
Figure 8. Effects of different waterproofing treatments on the setting time.
Figure 8. Effects of different waterproofing treatments on the setting time.
Buildings 16 01491 g008
Buildings 16 01491 g009
Figure 9. Effect of different waterproofing treatments on the fluidity.
Figure 9. Effect of different waterproofing treatments on the fluidity.
Buildings 16 01491 g009
Buildings 16 01491 g010
Figure 10. Water absorption test under different waterproofing treatments. (a) Before water immersion (Control group). (b) Before water immersion (SC-PE-8%). (c) Before water immersion (II-PE-8%). (d) Before water immersion (II-VAE-8%). (e) After water immersion (Control group). (f) After water immersion (SC-PE-8%). (g) After water immersion (II-PE-8%). (h) After water immersion (II-VAE-8%).
Figure 10. Water absorption test under different waterproofing treatments. (a) Before water immersion (Control group). (b) Before water immersion (SC-PE-8%). (c) Before water immersion (II-PE-8%). (d) Before water immersion (II-VAE-8%). (e) After water immersion (Control group). (f) After water immersion (SC-PE-8%). (g) After water immersion (II-PE-8%). (h) After water immersion (II-VAE-8%).
Buildings 16 01491 g010
Buildings 16 01491 g011
Figure 11. Effects of different waterproofing treatments on the water absorption.
Figure 11. Effects of different waterproofing treatments on the water absorption.
Buildings 16 01491 g011
Buildings 16 01491 g012
Figure 12. Effects of different waterproofing treatments on the flexural strength.
Figure 12. Effects of different waterproofing treatments on the flexural strength.
Buildings 16 01491 g012
Buildings 16 01491 g013
Figure 13. Effects of different waterproofing treatments on the compressive strength.
Figure 13. Effects of different waterproofing treatments on the compressive strength.
Buildings 16 01491 g013
Buildings 16 01491 g014
Figure 14. Effects of different waterproofing treatments on the contact angle.
Figure 14. Effects of different waterproofing treatments on the contact angle.
Buildings 16 01491 g014
Buildings 16 01491 g015
Figure 15. Mechanism of different waterproofing treatments.
Figure 15. Mechanism of different waterproofing treatments.
Buildings 16 01491 g015
Buildings 16 01491 g016
Figure 16. Microscopic structure under different dosages of incorporated paraffin emulsion.
Figure 16. Microscopic structure under different dosages of incorporated paraffin emulsion.
Buildings 16 01491 g016
Buildings 16 01491 g017
Figure 17. Microscopic structure under different dosages of incorporated VAE emulsion.
Figure 17. Microscopic structure under different dosages of incorporated VAE emulsion.
Buildings 16 01491 g017
Table 1. Factor level combinations of different waterproofing treatments.
Table 1. Factor level combinations of different waterproofing treatments.
NumberNameWaterproofing TreatmentsTypes of EmulsionDosages/%Mechanism
1Control group----
2SC-PE-2%Surface coatingParaffin emulsion2%Forms a hydrophobic film on the surface, preventing water infiltration
3SC-PE-4%4%
4SC-PE-6%6%
5SC-PE-8%8%
6II-PE-2%Internal incorporation2%Distributes paraffin particles within the matrix, creating a stable hydrophobic barrier for long-lasting waterproofing
7II-PE-4%4%
8II-PE-6%6%
9II-PE-8%8%
10II-VAE-2%Vinyl acetate-ethylene copolymer emulsion
(VAE emulsion) 		2%Forms a continuous polymeric films, sealing gaps between crystals, reducing water infiltration, and ensuring long-term waterproofing
11II-VAE-4%4%
12II-VAE-6%6%
13II-VAE-8%8%
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Li, Z.; Li, Z.; Rao, S.; Li, D.; Lu, D.; Zhu, H.; Liu, C.; Shi, J.; Wang, X. Effect of Paraffin and Vinyl Acetate Ethylene (VAE) Emulsions on the Waterproofing and Mechanical Properties of Fiber-Reinforced Modified Gypsum (FRMG) Matrix. Buildings 2026, 16, 1491. https://doi.org/10.3390/buildings16081491

AMA Style

Li Z, Li Z, Rao S, Li D, Lu D, Zhu H, Liu C, Shi J, Wang X. Effect of Paraffin and Vinyl Acetate Ethylene (VAE) Emulsions on the Waterproofing and Mechanical Properties of Fiber-Reinforced Modified Gypsum (FRMG) Matrix. Buildings. 2026; 16(8):1491. https://doi.org/10.3390/buildings16081491

Chicago/Turabian Style

Li, Zhenxing, Zuohua Li, Shaohua Rao, Dongning Li, Dejing Lu, Huaitao Zhu, Changyuan Liu, Jianzhe Shi, and Xin Wang. 2026. "Effect of Paraffin and Vinyl Acetate Ethylene (VAE) Emulsions on the Waterproofing and Mechanical Properties of Fiber-Reinforced Modified Gypsum (FRMG) Matrix" Buildings 16, no. 8: 1491. https://doi.org/10.3390/buildings16081491

APA Style

Li, Z., Li, Z., Rao, S., Li, D., Lu, D., Zhu, H., Liu, C., Shi, J., & Wang, X. (2026). Effect of Paraffin and Vinyl Acetate Ethylene (VAE) Emulsions on the Waterproofing and Mechanical Properties of Fiber-Reinforced Modified Gypsum (FRMG) Matrix. Buildings, 16(8), 1491. https://doi.org/10.3390/buildings16081491

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop