Waterproofing Membrane Research Articles

Study of the tightness of single seams of LOGICBASE™ / ECOBASE™ PVC membranes in engineering waterproofing systems

Objective. Currently, engineering waterproofing systems with polymer waterproofing membranes are widely used at various construction structures. At the same time, the usage of polymer membranes implies the operation of break welds, the strength of which should be no less than the strength of the waterproofing material itself. The purpose of the study is to evaluate the water resistance of single seams (without test channels, welded by manual or automatic equipment) for LOGICBASE™ / ECOBASE™ grade V-SL polymer membranes at a pressure of 1 MPa. Method. Testing of waterproofing seams for water resistance is carried out according to the requirements of GOST EN 1928-2011, method B. The GESTER model GT-C26B hydrostatic pressure testing device is used as a test installation. LEISTER welding equipment of Varimat V2 (automatic equipment) and Triac AT (manual/hand equipment) models was used for welding samples. The width of the weld was at least 30 mm. Result. At a hydrostatic head pressure of 1 MPa, within 24 hours from the start of the test, there were no traces of water penetration in the samples, which indicates that the seams are completely waterproof. Conclusion. Single seams of LOGICBASE™/ECOBASE™ engineered waterproofing PVC membranes are completely sealed at 1 MPa water pressure.

Influence of waterproof and breathable membrane on thermal comfort properties of multi-layer clothing system

Influence of waterproof and breathable membrane on thermal comfort properties of multi-layer clothing system

Biocompatible, robust, waterproof and breathable PDMS-based PU fibrous membranes for potential application in wound dressing

Wound dressings, an effective tool for repairing injured skin and protecting it from secondary damage, have been widely manufactured. However, the design of wound dressings with waterproofness, breathability, mechanical robustness, and excellent biocompatibility remains a challenge due to the imbalance between the multiple desirable properties. Herein, a strategy is proposed to fabricate biocompatible membranes via a facile one-step electrospinning method. Polydimethylsiloxane-based polyurethane is effectively prepared to form durable hydrophobic surfaces, resulting in a high degree of hydrophobicity (141.0° water contact angle). The porous structure is enhanced by adjusting the solution concentration and heat treatment temperature, resulting in an optimal water vapor transmission rate of 8.2 kg·m−2·h−1. Additionally, the membrane exhibits a hydrostatic pressure of 52.3 kPa, which is approximately 14.1 times greater than that of PU fibrous membrane, and an enhanced tensile strength of 6.60 MPa. Moreover, the membrane can be utilized in a wide temperature range from − 123 °C to 160 °C due to its low glass transition temperature and exceptional thermal stability. Significantly, both in vitro and in vivo studies confirmed the remarkable biocompatibility and minimal toxicity to normal cells and mice skin. Our work presents a new approach to designing waterproof and breathable biomaterials with high mechanical strength, thereby enhancing their performance and functionality in the biomedical field, particularly in wound dressing applications.

Temperature Condition Analysis for Freezing on Tunnel Lining Back Side According to Tunnel Length

Railway mountain tunnels were constructed in cold regions of Korea recently, and freezing has been generated. Most mountainous railway tunnels are designed with waterproofing membranes since groundwater exists on the backside of the tunnels. The lower air temperature inside the tunnel is transferred to the back of the tunnel lining as the outside air temperature drops below zero in winter, causing the groundwater behind the waterproofing membrane to freeze. There have been cases of freezing-related damage, such as the obstruction of drainage flow and freezing groundwater leakage. Therefore, the freezing conditions inside the tunnel should be analyzed by each tunnel length after the air temperature variation in the tunnel is measured. In this study, the air temperature inside a railway tunnel located in a cold region was measured using thermometers. The inside air temperature over time was changed by the DTR (diurnal temperature range) every 24 h. The DTR inside the tunnel was also reduced far from the entrance. Heat transfer analysis was implemented considering the air temperature variation inside the tunnel. Assuming that the minimum air temperature freezing inside the tunnel lasts seven days, the higher the minimum air temperature the longer the tunnel length. The research results show that the freezing inside a tunnel can be estimated from the tunnel length and the minimum air temperature inside the tunnel.

Research on waterproof performance and mechanism of organic silane waterproof membrane

In this paper, the subgrade waterproof membrane was proposed to achieve single-direction water-blocking by inhibiting the capillary rise and the downward infiltration of subgrade water. Further, the vertical migration mechanism of water in the waterproof membrane was revealed from the fluid potential perspective. It is found that when the consumption of Organic Silane per unit Area (OSA) is 0–4 g/m2, the water can migrate vertically and the waterproof membrane cannot inhibit the capillary rising, whereas the subgrade rainfall can infiltrate downward. At 6 g/m2, the capillary rise height of 20 cm can be inhibited, and the subgrade rainfall can infiltrate downward. At 8 g/m2, the capillary cannot rise, and the subgrade rainfall can infiltrate. At 10 g/m2 and 15 g/m2, the capillary cannot rise, subgrade rainfall is difficult to infiltrate downward, and water is difficult to migrate vertically in the waterproof membrane. Choosing 10 g/m2 consumption of OSA in the subgrades is recommended.

High-Performance Waterproof, Breathable, and Radiative Cooling Membranes Based on Nanoarchitectured Fiber/Meshworks.

Smart membranes with protection and thermal-wet comfort are highly demanded in various fields. Nevertheless, the existing membranes suffer from a tradeoff dilemma of liquid resistance and moisture permeability, as well as poor thermoregulating ability. Herein, a novel strategy, based on the synchronous occurrence of humidity-induced electrospinning and electromeshing, is developed to synthesize a dual-network structured nanofiber/mesh for personal comfort management. Manipulating the ejection, deformation, and phase separation of spinning jets and charged droplets enables the creation of nanofibrous membranes composed of radiative cooling nanofibers and 2D nanostructured meshworks. With a combination of a true-nanoscale fiber (∼70 nm) in 2D meshworks, a small pore size (0.84 μm), and a superhydrophobic surface (151.9°), the smart membranes present high liquid repellency (95.6 kPa), improved breathability (4.05 kg m-2 d-1), and remarkable cooling performance (7.9 °C cooler than commercial cotton fabrics). This strategy opens up a pathway to the design of advanced smart textiles for personal protection.

One-step fabrication of strengthened breathable composite nanofiber membranes by electrospinning/electrospraying for highly waterproof application

Waterproof breathable membranes (WBMs) have attracted intense research interest due to their wide applications, however, there are still great challenges in effectively preparing WBMs with desirable waterproofness, breathability and elasticity. Here, a facile and scalable fabricating strategy combining electrospinning and electrospraying is proposed to manufacture nanofiber WBMs, which are comprised of both hydrophobic thermoplastic polyurethane (TPU) nanofibers and inter-fiber polyvinyl butyral (PVB) bonding containing a short perfluoroalkyl hydrophobic agent. The obtained composite nanofiber membranes showed durable water/oil repellent properties against ultrasonic washing and abrasion. The interconnected fibrous structure together with liquid repellent surface have endowed the WBMs with comprehensive properties with hydrostatic pressure of 73.7 kPa, water vapor transmission rate of 6.88 kg m−2 d−1, outstanding tensile strength of 25.72 MPa and large elongation at break of 217%, which have exceeded the majority of their nanofiber counterparts. This work could provide a novel approach for the preparation of waterproof and breathable membranes with balanced structural stability, waterproofness and wearing comfort, especially suitable for the personal protective material application.

Study on single-direction water-blocking of waterproof membrane in silt subgrade

This paper proposes a new concept of single-direction water-blocking for waterproof membranes in silt subgrades to meet the demands of inhibiting capillary rising and allowing subgrade water downward through the waterproof membrane. Furthermore, a new approach to determine the total pore area in water-repellent soil is proposed using a contact angle test. The relationship between the water repellence of the waterproof membrane and the consumption of Sodium Methyl Silicate per unit Area (SMSA) is obtained for different levels of compactness. When SMSA consumption is less than 4 g/m2, the water repellence of the waterproof membrane is extremely poor, whereas, in the range of 4–10 g/m2, its water repellence is greatly enhanced. When the SMSA consumption is more than 10 g/m2, the water repellence becomes stable. The total pore area of the waterproof membrane decreases when the SMSA consumption is increased.

Kajian Kes: Kebocoran Antara Tingkat di Bangunan Kediaman Bertingkat Malaysia

Building defects are a common issue in the construction industry. Defects of high-rise buildings, such as cracks and leaks, are often caused by poor workmanship, and insufficient and low-quality building materials. Other contributing factors to building defects are inadequate cooperation during construction, poor design and improper installation. Inter-floor leakage is a widespread matter in new homes, leaks are detected late and repeated leaks occur even after repairs have been carried out. Inter-floor leakage often occurs in new homes. Leaks are detected late and repeated ones occur even after repairs are carried out. This study aims to diagnose buildings with inter-floor leakage problems by using several diagnostic tools and techniques like visual, destructive and non-destructive tests. Experts use testing equipment to determine moisture and appropriate maintenance or repair. A case study is carried out on a residential unit with a leak in the ceiling due to a crack on the rooftop. The findings of the study can provide knowledge about building diagnosis to property owners and property managers, identifying the cause of leaks and enabling early detection of building defects and suggested repairs to prevent similar leaks from occurring. By utilizing diagnostic tools and techniques, owners and property managers can detect problems early, minimizing damage and expenses in the long run. Based on the study, existing cracks can be converted into expansion joints, white paint can be used on the walls to control heat, installed thermal insulation to control solar energy stress and waterproof membrane can be applied to prevent moisture penetration.

Advancements in Electrospun Nanofibrous Membranes for Improved Waterproofing and Breathability

AbstractElectrospun nanofibrous membranes have attracted significant interest due to their captivating waterproof and breathable characteristics, stemming from the presence of interconnected and hydrophobic channels within these enhanced textiles. These distinctive traits bestow upon them substantial potential across various domains, encompassing applications in medical dressings, masks, and protective clothing. However, they also give rise to concerns about their durability, compromised waterproofing performance, limited breathability, insufficient mechanical strength, and high production costs. Furthermore, the manufacturing processes of electrospun waterproof and breathable membranes (WBMs) may carry adverse environmental implications, necessitating improvements in sustainability and ecological compatibility. This study begins with a concise overview of the operational principles and criteria for performance evaluation relevant to electrospun WBMs, providing comprehensive guidelines to drive future research. Following this, the authors delve into a thorough exploration of typical fabrication techniques and the prevailing strategies, exemplified by noteworthy ongoing research initiatives. Last, the existing challenges are outlined to foster the development of WBMs. In addition, future research directions and perspectives are presented to expedite the advancement of WBMs and support their commercial implementation. It is anticipated that this comprehensive review will offer pragmatic recommendations for researchers dedicated to the advancement of WBMs.

Determination of the stress-strain demand curve of the sprayed waterproofing membrane interface in composite SCL tunnels

Understanding the evolution of the stress-strain states of the sprayed waterproofing membrane within composite sprayed concrete lined (SCL) tunnels from the short-term dry condition to the long-term wet condition is critical to ensure the integrity of the composite SCL tunnels. This paper presents a conceptual framework describing the evolution of the states and demonstrates a methodology that enables the designer to determine the states using a demand curve that bounds all possible stress-strain states of the membrane interface.It firstly presents a conceptual framework for the evolution of the state stress and strain of the membrane interface in typical composite SCL tunnels from short to long term and from ‘dry’ to ‘wet’ membrane saturation. A numerical method to simulate this evolution is presented. A numerical analysis of a full composite SCL tunnel in typical over-consolidated ground was carried out for the range of possible locations of groundwater pressure application in the lining, and the results used to demonstrate the process of obtaining a set of stress-strain demand curves for the tunnel.The research shows that the membrane interface in a composite SCL tunnel is in a state of combined normal and shear stress and strain but that these stresses and strains remain finite and do not become unbounded, due to the statically indeterminate nature of the structure. It is however an interaction problem so that the normal and shear stress and strain need to be checked together. Some insights are given as to the nature of a laboratory testing programme that could be carried out on the membrane interface to obtain capacity envelopes to compare with the demand curves for design.

Spray-applied waterproofing membranes in tunnelling: A construction perspective

Spray-applied waterproofing membranes have received a lot of press and attention in recent years, but the coverage has in large either been design focussed or driven by the material suppliers of such membranes or opponents of the approach. This paper aims to provide a comprehensive overview of the limitations and advantages of spray-applied waterproofing membranes from a practical construction perspective. It discusses the logistic benefits compared to traditional sheet membranes, but also highlights the hidden complexities and impacting factors that are often not fully transparent. The paper covers activities that need to be considered when scheduling or costing such works and provides a general basis for the preparation of Work Method Statements. It also covers contractual constraints, requirements under current international and national standards and regulations, pre-production trials, and quality testing requirements. OH&M considerations are also addressed. Additionally, the paper identifies complementary tasks that are often overlooked but are necessary for a successful membrane installation. These tasks include pre-production trials and quality testing requirements, as well as other activities that need to be considered when choosing a sprayed waterproofing solution. The paper concludes by summarizing the requirements stated by different material manufacturers. All of this is complemented by the authors own experience and observations, and a summary of the consequences drawn from the reviewed data. Consequently, an overview on the aspects of usage of a sprayed-applied membrane material is presented, which the author hopes will provide some practical guidance for the evaluation of the suitability and application of such a product.

A Facile and Strategic Approach to Superhydrophobic Fibrous Structure with Biaxially Aligned Electrospun Porous Fibers

AbstractElectrospun fibrous structures can be developed superhydrophobic while remaining breathable. However, current electrospinning‐based methods for developing superhydrophobicity require complex fabrication processes and multiple raw materials, lacking a facile approach to superhydrophobicity using electrospun fibers. Inspired by a cultural relic known as Plain Gauze Gown, a fibrous structure consisting two layers of porous fibers aligned in warp and weft directions by simple electrospinning is developed. Through investigation of wetting behavior, an unique Cassie–Baxter‐“restoring” (CaRe) wetting contributing to a stable Cassie–Baxter state is unveiled in the developed structure. The CaRe wetting ensures that droplet stays on the upper‐layer fibers even at a sparse inter‐fiber distance, enabling strategically reaching superhydrophobicity by lowering structure solidity. Remarkably, the developed structure with water contact angle between 159° and 162° and roll‐off angle from 10° to 3° has a water vapor transmission rate of 20.8 kg m−2 d−1, which is the highest value among all superhydrophobic electrospun structures reported, and it is also waterproof and semi‐transparent. These features make the structure suitable for a wide range of applications, including developing waterproof, breathable, and superhydrophobic membrane with simple preparation and low cost, and as a surface layer for wearable electronics that facilitates sweat evaporation and prevents water intrusion.

Investigation of Correlation between Component and Molecular Structure of Bitumen and Properties of High-Dosage Styrene-Butadiene-Styrene–Modified Bitumen for Waterproof Membrane

Abstract In this article, the correlation between components and molecular structures of base bitumen and properties of high-dosage styrene-butadiene-styrene–modified bitumen (HSMB) for waterproof membrane was investigated. Saturates, aromatics, resins, and asphaltenes (SARA components) of eight base bitumens from different crude oils used to prepare HSMB were analyzed by column chromatography, and the molecular structures of these base bitumens were obtained by proton nuclear magnetic resonance, gel permeation chromatography, elemental analysis, and an improved Brown-Ladner calculation method. Softening point and low-temperature flexibility tests were used to estimate the high- and low-temperature performance of HSMBs. The results showed that the highest softening point of the HSMBs was 119.2°C, whereas the lowest was 102.5°C. The best flexibility of HSMB was −24°C, and the worst was −10°C. The softening point of HSMB raised with the increase of the content of saturates and aromatics, aromatic carbon ratio (fA), and condensation index (CI) while decreasing with the increase of H/C. The flexibility of HSMBs was most significantly influenced by the content of saturates, and when the saturate content was 17 %, the flexibility was optimal. However, the flexibility of HSMB was poor when the number average molecular weight (Mn) of bitumen was large. To prepare HSMB with excellent performance, it is recommended that the content of saturates should be between 12 and 17 %, aromatics content should be between 45 and 55 %, resins and asphaltenes content should not be excessive, and fA > 0.25, CI > 0.17, H/C ≤ 1.55.

A Study on Verification of Waterproofing Method Properties for Performance Grading in Apartment Houses-Upper Slab of the Underground Structure

This study evaluates waterproofing methods for underground structures in multi-unit residential buildings. The objective is to select effective methods and establish performance ratings. Experimental assessments are conducted and scores are assigned for ranking. In this regard, waterproofing methods used in the upper slab of the top floor of multi-unit residential building underground structures were investigated, and they were categorized as composite waterproofing, sheet waterproofing, and membrane waterproofing methods. For performance evaluation purposes, experiments were conducted on qualified materials and scores were assigned to each test specimen, with a total score of 100 points. Based on the test results, scores for disqualified materials were deducted and, ultimately, the rankings of waterproofing materials and methods for the upper slab of the top floor of underground structures were determined based on the total aggregated scores. Subsequently, through proximity performance evaluation, the applied waterproofing methods were experimentally verified for defect issues based on the presence or absence of a proximity layer. This led to the ranking and performance grading of a total of 12 materials. The results confirmed the necessity of a proximity layer-dependent waterproofing method and highlighted the superiority of the composite waterproofing method with a proximity layer. Additionally, differences in installation methods and material properties between sheet and membrane waterproofing methods were identified, resulting in variations in performance grading.

Poly(methyl methacrylate) embedded fluorine-free polyurethane electrospun nanofiber membranes with enhanced waterproof and breathable performance

Waterproof and breathable membranes (WBMs) are desirable for protective materials; however, the existing WBMs are limited by fluorine-containing materials and complicated post-treatments. Herein, we innovatively designed fluorine-free polyurethane/poly (methyl methacrylate) (PU/PMMA) WBMs by one-step electrospinning technology. Benefiting from the introduction of hydrophobic PMMA, PU/PMMA WBMs presented higher hydrophobicity, smaller pore size, higher porosity, higher acid fastness, and stronger mechanical strength, which are favorable for the improvement of waterproofness, breathability, chemical resistance, and mechanical property. The resultant PU/PMMA-3 WBM exhibited good hydrostatic pressure (56.0 kPa), high moisture permeability (10.5 kg m-2 d-1), and high tensile strength (8.2 MPa). Besides, the PU/PMMA-3 WBM displayed outstanding chemical resistance. These results suggested that the PU/PMMA WBMs could be widely used in applications such as protective materials and wound dressings.

Rainwater Retention Test of Various Green Roofs: Influence on Membrane Temperatures and Evapotranspiration

Green structures such as roofs or facades are great examples of ways to mitigate climate change, and they have multidisciplinary benefits. One of them is water retention during storms and high rainfalls. In this paper, the impact on the temperature of a membrane after excessive watering was investigated. The results of watered samples were compared to the non-watered ones. This test was carried out on five equal samples. The results showed that the actual foliage cover is very important. The worst results were obtained by the samples that did not have sufficient plant (foliage) cover. Notable differences in courses after watering reached up to 7 °C and lasted up to five days. Visible differences after watering were also exhibited by other samples. The type of drainage/retention layer also influenced the results, whereas the hard-profiled plastic board had high practical retention, which impacted temperatures over a long time period. The actual water content influenced and reduced the daily amplitude from 13 to 7 °C for at least five sunny days. This confirms the theoretical evapotranspiration calculations and actual water content in green roofs. In this case, the water content in the samples proves the cooling effect on the waterproofing membrane.

Review of Waterproof Breathable Membranes: Preparation, Performance and Applications in the Textile Field.

Waterproof breathable membranes (WBMs) characterized by a specific internal structure, allowing air and water vapor to be transferred from one side to the other while preventing liquid water penetration, have attracted much attention from researchers. WBMs combine lamination and other technologies with textile materials to form waterproof breathable fabrics, which play a key role in outdoor sports clothing, medical clothing, military clothing, etc. Herein, a systematic overview of the recent progress of WBMs is provided, including the principles of waterproofness and breathability, common preparation methods and the applications of WBMs. Discussion starts with the waterproof and breathable mechanisms of two different membranes: hydrophilic non-porous membranes and hydrophobic microporous membranes. Then evaluation criteria and common preparation methods for WBMs are presented. In addition, treatment processes that promote water vapor transmission and prominent applications in the textile field are comprehensively analyzed. Finally, the challenges and future perspectives of WBMs are also explored.

Tuning the properties of breathable polyurethanes through chemical crosslinking

AbstractThe present work aims at improving the properties of waterproof breathable polyurethane membranes by introducing chemical crosslinks. A series of crosslinked polyurethanes were prepared by chain extension of prepolymer containing varying amounts of a triisocyanate‐based crosslinker (0–15% wt/wt). Thin polyurethane films (~40 μm) were prepared by a solution casting technique and the effect of introducing the crosslinker on thermal, mechanical characteristics was established. Crosslinking led to an increase in glass transition temperature. All crosslinked polyurethanes exhibited a sub‐ambient Tg. Both tensile and tear strengths were found to improve with crosslinking. Crosslinking (15% wt/wt) led to an increase in waterproofness from 112 ± 11 mbar to 574 ± 23 mbar, while the breathability reduced from 1246 ± 52 g/m2/day to 678 ± 32 g/m2/day. Polyurethane membranes containing 10% crosslinker exhibited an optimal balance of waterproofness and breathability, where the film was found to possess a water vapor transmission rate (WVTR) of 834 ± 37 g/m2/day with a hydrostatic pressure of 490 ± 18 mbar. This was subsequently coated on a cotton–polyester fabric to fabricate a breathable textile which was found to exhibit a WVTR of 663 ± 18 g/m2/day and a hydrostatic pressure of >3 bar, which was suitable for practical applications.

Unconventional Arrays for 3D Electrical Resistivity and Induced Polarization Tomography to Detect Leachate Concentration in a Waste Landfill

In recent times, 3D electrical resistivity and induced polarization tomographies are being used more frequently. However, it is often not possible to have regular grids of electrodes due to irregular topography, difficulty accessing urbanized or industrialized places, and other environmental and health problems. In these cases, the use of unconventional arrays is necessary, arranging the electrodes around the inaccessible area according to one or more open or closed polygonal traces. In this work, three different perimeter arrangements of electrodes are considered, and, for each, three different electrode array configurations are tested by calculating their apparent resistivity and solving the inverse problem on a three-dimensional model with resistive and conductive blocks. The comparison of the results showed that the dataset that produces the most realistic inverse model consists of electrodes arranged in concentric squares and the use of the Full Range Gradient (FRG) Array. This combination was evaluated in the field on a waste landfill, in which electrical resistivity and induced polarization tomographies were carried out, exploiting the access paths to the various sectors of the landfill to arrange the electrodes on approximately concentric polygons. The 3D models of electrical resistivity and induced polarization allowed the detection of zones of high concentration of leachate, defining their extension, and monitoring the functioning of the waterproofing membrane at the bottom of the landfill. The results proved that when it is not possible to arrange a regular grid of electrodes, the use of perimeter disposals of electrode joined to the FRG array provide a sufficiently homogeneous resolution below the area to be investigated.