When subjected to external loads from the ground and nearby construction,tunnel segmental lining joints are prone to damaging deformation.This can result in water leakage into tunnels,posing great safety risks.With th...When subjected to external loads from the ground and nearby construction,tunnel segmental lining joints are prone to damaging deformation.This can result in water leakage into tunnels,posing great safety risks.With this issue in mind,we conducted a series of full-scale tests to study the effects of external loads on the waterproofing performance of longitudinal joints.A customized rig for testing segmental joints was developed to assess the effect of loading magnitude,eccentricity,and loading-unloading-reloading cycles on waterproofing performance.Additionally,the relationship between joint force,sealing gasket deformation,and waterproofing pressure was investigated.The results indicate that:(1)the sealing gasket’s compression rapidly decreases as external loads increase,which weakens the waterproofing capacity of the joint;(2)the watertightness limit dramatically decreases as the bending moment increases;(3)a loading-unloading-reloading cycle leads to degradation of the joint’s waterproofing performance.The findings of this study provide a reference for subsequent waterproofing design of segmental tunnel joints,helping ensure the safety of tunnels throughout their operational lifespans.展开更多
The waterproof construction of subway tunnels is a crucial and challenging aspect of subway tunnel engineering.Mastering excellent waterproof construction technology is essential to ensure that the construction meets ...The waterproof construction of subway tunnels is a crucial and challenging aspect of subway tunnel engineering.Mastering excellent waterproof construction technology is essential to ensure that the construction meets design requirements and guarantees the safe operation of subway lines.This paper focuses on discussing waterproof construction technology for subway station tunnels.By analyzing the main methods and techniques of underground tunnel construction,as well as the key techniques and difficulties of waterproofing construction,this paper examines the waterproofing construction project of Guangzhou Metro Culture Park Station as a case study.It analyzes the methods,quality management practices,and safety management strategies applied in the project.This paper serves as a reference for tunnel engineering design and construction units in our country,offering insights into effective waterproof construction techniques for subway tunnels.展开更多
As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environm...As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environments. In recent years, with the development of undersea tunnel construction, the design and construction technologies have been greatly enhanced. The first undersea tunnel in China has just been built. Waterproofing is the key technique of undersea tunneling. A new concept of waterproofing scheme of grouting, sealing, draining and divided sections was adopted in the construction of the tunnel based on the researches, the in-situ geological features, the astuteness of the current technology and the cost of construction. The structural details of the sealing and draining system are introduced to illustrate the salient features of the new waterproofing technique. It is hoped that experiences described in the paper can offer guidance for the construction of the extensive undersea tunnels in the coming years.展开更多
The modified petroleum resin emulsion prepared from the C9petroleum resin was modified with maleic anhydride.The effects of maleic rosin and maleic anhydride addition level,the modification time and the alkali liquor ...The modified petroleum resin emulsion prepared from the C9petroleum resin was modified with maleic anhydride.The effects of maleic rosin and maleic anhydride addition level,the modification time and the alkali liquor on the properties of the emulsion were discussed.The results showed that the optimum process conditions covered:a maleic anhydride mass fraction of 1.5%,a maleic rosin mass fraction of 10%,a KOH mass fraction of 1%,a petroleum resin modification temperature of 200℃,a petroleum resin modification duration of 3 h,and a modified petroleum resin emulsion/wax emulsion mixing ratio of 1:1.The particle size of modified petroleum resin emulsion prepared under these conditions was equal to 104.166μm.展开更多
Polyurethane dispersions (PUD) have diversified into a myriad of applications over the years. This has led to extensive research on both industrial and laboratory fronts as polyurethane dispersions provide liberty to ...Polyurethane dispersions (PUD) have diversified into a myriad of applications over the years. This has led to extensive research on both industrial and laboratory fronts as polyurethane dispersions provide liberty to interplay at the molecular level to diversify the properties of the product which has also led to the development of eco-friendly waterborne dispersions. Yet, waterborne PUDs are limited in their mechanical and physical properties as compared to solvent-based products. The incorporation of crosslinkers in the PUD further bolsters these properties thus improving water and solvent resistance. The incorporation of silanols increases solvent resistance and adhesion of the resultant PUD. In this work, a post crosslinking system based on the ketone-hydrazine mechanism was incorporated into the PUD thus providing the required structural reinforcement for construction application. The targeted application for this work is the use of PUDs for waterproofing.展开更多
To address the need for producing a cheap,single-component,hot-applied compound joint sealant with high quality for sealing joints and cracks in concrete and flexible pavements without using primer for installation,a ...To address the need for producing a cheap,single-component,hot-applied compound joint sealant with high quality for sealing joints and cracks in concrete and flexible pavements without using primer for installation,a hot-applied modified asphalt sealant was produced by blending up about 30% starch into 20% citric acid.The starch and the asphalt cement were mixed at a temperature of above 160 ℃.Thus the waterproofing asphalt was manufactured to protect the surface of various shapes and types from water leakage using the citric acid.Results indicate that this sealant complies with the requirements of ASTM D-1191,D-6690-06a and D-7116-05.The citric acid is a kind of reliable materials for asphalt cement,which can be widely used in paving and waterproofing construction materials,and this offers profound engineering and economic advantages.展开更多
In the construction of civil engineering projects, the application of roofing waterproof technology is a key construction content that should be paid attention to based on the safety and convenience of the application...In the construction of civil engineering projects, the application of roofing waterproof technology is a key construction content that should be paid attention to based on the safety and convenience of the application of building construction after the completion of the basic frame construction of the building entity and the core project of the entity part construction. In the concrete implementation of roofing waterproof construction, professional technology needs to be applied, and the application of waterproof technology should be assisted to achieve good waterproof effect in combination with the construction technology requirements of each link of roofing. Specifically, in civil engineering projects, the application of roofing waterproof technology needs to find targeted waterproof technology in combination with different building entity areas. In addition, the quality control of raw materials in waterproof construction, construction of waterproof layer, design and construction of drainage system may affect the application effect of waterproof construction technology. Based on this, it is necessary for construction personnel and management personnel to guarantee the effective application of waterproof technology from the aspects of raw material construction technology and construction management.展开更多
At present, the height of the building is increasing, and the depth of the foundation is also increasing. All construction units are also increasing their efforts to develop underground space. The basement is the basi...At present, the height of the building is increasing, and the depth of the foundation is also increasing. All construction units are also increasing their efforts to develop underground space. The basement is the basic part of the building structure system, and its waterproof performance must be guaranteed, otherwise it will threaten the stability of the basement and even the whole building. It is particularly important to control the construction quality of basement waterproofing works, which can not only provide security for peoples daily use of basements, but also promote the long-term development of Chinas construction industry. Based on this, this paper explores the quality measures of basement waterproofing construction in high-rise building projects.展开更多
Double-bonded spray membrane waterproofing materials have excellent waterproofing performance and can improve the load-bearing capacity of tunnel linings,leading to an increasing global application.However,due to the ...Double-bonded spray membrane waterproofing materials have excellent waterproofing performance and can improve the load-bearing capacity of tunnel linings,leading to an increasing global application.However,due to the double-bonded capability of spray membrane materials,traditional interlayer drainage methods cannot be applied.This limitation makes it difficult to use them in drainage-type tunnels,significantly restricting their range of applications.In this regard,a novel tunnel waterproof-drainage system based on double-bonded spray membrane materials was proposed in this paper.The proposed drainage system primarily comprises upper drainage sheets and bottom drainage blind pipes,both located in the tunnel circumferential direction,as well as longitudinal drainage pipes within the tunnel.Subsequently,numerical calculation methods are employed to analyze the seepage characteristics of this system,revealing the water pressure distribution around the tunnel.The results indicate that in the novel waterproof-drainage system,the water pressure in the secondary lining exhibits a“mushroom-shaped”distribution in the circumferential direction,while the water pressure in the longitudinal direction exhibits a“wave-like”distribution.Furthermore,comparative results with other waterproof-drainage systems indicate that under typical working conditions with a water head of 160 m and a rock permeability coefficient of 10^(−6)m/s,the maximum water pressure in the secondary lining of the novel waterproof-drainage system is 0.6 MPa.This represents a significant reduction compared to fully encapsulated waterproofing and traditional drainage systems,which respectively reduce the water pressure by 65%and 30%.The applicability analysis of the double-bonded waterproofing and drainage system reveals that it can reduce at least 40%of the static water pressure in any groundwater environments.The novel drainage system provides a valuable reference for the application of double-bonded spray membrane waterproofing materials in drainage-type tunnels.展开更多
The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-orga...The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-organic frameworks(MOFs),the multifunctional environment remediation materials,to be applied in heritage environmental protection.The advantages of MOFs lie in their multifunction like adsorption,photocatalysis,sterilization,as well as the controllable structure and properties that could be flexibly adjusted as demands,helping the heritage against various environmental threats.Thereby,the applications and the corresponding mechanisms of MOFs in cultural heritage preservation were reviewed in this work,including harmful gas adsorption,surface waterproofing,particulate matters(PM)removal,anti-bacterial and humidity control of environment.Finally,the selection principles and precautions of MOFs in heritage preservation were discussed,aiming to provide a forward-looking direction for the selection and application of MOFs.展开更多
Purpose–Salt rock from salt lakes can serve as a cost-effective material for subgrade filling,as demonstrated in projects like the Qarhan Salt Lake section of the Qinghai-Tibet Railway and the Qarhan Salt Lake sectio...Purpose–Salt rock from salt lakes can serve as a cost-effective material for subgrade filling,as demonstrated in projects like the Qarhan Salt Lake section of the Qinghai-Tibet Railway and the Qarhan Salt Lake section of the G215 Highway.This state-of-the-art paper aims to summarize the engineering properties of salt rock filling and present the advances of its utilization.Design/methodology/approach–This paper collects and analyzes laboratory and field data of salt rock filling from previous studies to present a comprehensive analysis of the engineering properties and utilization of salt rock fillings.Findings–Salt rock primarily contains minerals such as halite and glauberite,which contribute to its unique phase-changing behavior under varying environmental conditions,impacting its mechanical properties.Salt rock filling shrinks when in contact with vapor or unsaturated brine and expands under cooling or evaporation.Its use is particularly recommended for arid regions,with specific restrictions depending on the structure type.This paper discusses suggested countermeasures to mitigate these issues,as well as key quality acceptance indices for salt rock filling compaction.Moisture content after air-drying is recommended as a crucial parameter for construction quality control.Originality/value–This review aims to support future research and engineering practices in salt rock subgrade applications.展开更多
The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof per...The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof performance for certain tunnels with high water pressure,especially water-conveyance tunnels.This paper presents a series of waterproofing tests on joints with different settings of double gaskets via an improved test apparatus.Four cases are investigated,including(i)double gaskets with equal high/low waterproof capacity,(ii)the outer gasket with higher waterproof capacity,and(iii)the outer gasket with lower waterproof capacity.Different joint openings are also considered.Moreover,the water pressures at two cavities are continuously monitored to highlight the waterproofing mechanism and failure pattern of double gaskets.The results demonstrate that the gasket with the higher waterproofing capacity dominates the overall waterproofing capacity of joint with double gaskets;only a little enhancement of the waterproofing capacity is found for the joint with the same double gaskets.The waterproofing capacity of joints with double gaskets decreases with the increase of the joint opening.The failure pattern depends on the arrangement of double gaskets,and four stages can be identified during the whole failure process.The advantages of double gaskets in case of joint rotation are also discussed.展开更多
Establish an efficacy evaluation method for foundation products in vivo and vitro.The hiding power,whiteness,waterproof and anti-sweat effect were evaluated in vitro test,where CR ratio,Individual Type Angle (ITA°...Establish an efficacy evaluation method for foundation products in vivo and vitro.The hiding power,whiteness,waterproof and anti-sweat effect were evaluated in vitro test,where CR ratio,Individual Type Angle (ITA°) and chromatic aberration (E) were measured as evaluation indicators by standard black/white cardboard,artificial leather and artificial sweat.In clinical assessment,the anti-stain,waterproof,anti-sweat effect of the foundation products were evaluated through the ΔE change,before and after the treatment of products by staining,wetting,sweating in forearm skin.There were significant differences in CR ratio of different types of samples on standard black and white cardboards (P<0.05),ITA° of artificial leather has a significant increase after treatment (P<0.05),?E﹤1.5 in black cloth after dipping test,while ΔE﹤1.5 in leather after water and artificial sweat treatment.Clinical assessment showed that ?E ﹤50%,which had no significant difference in human skin color,before and after the test (P>0.05).The change trend of efficacy evaluation in vitro test was basically consistent with that of visual evaluation and clinical assessment,indicated that the efficacy evaluation methods of foundation products in vivo and vitro are intuitive,quantifiable,and can be used to evaluate the efficacy of foundation products.展开更多
The waterproof performance,mechanical properties,chemical composition,microstructure,and pore structure of hydrophobically-modified geopolymer concrete are investigated before and after dry-wet cycles,to determine the...The waterproof performance,mechanical properties,chemical composition,microstructure,and pore structure of hydrophobically-modified geopolymer concrete are investigated before and after dry-wet cycles,to determine the long-term feasibility of using hydrophobically-modified geopolymer concrete in wet environments.We use two types of organic modifying agents:polydimethylsiloxane(PDMS)and sodium methyl siliconate(SMS).The experimental results show that incorporating 2%–6%PDMS or 5%–15%SMS can make the concrete hydrophobic,with water absorption and chloride transport rates decreasing by up to 94.3%.We also analyze the bonding modes of organic molecules and geopolymer gels,as well as their evolution mechanisms during dry-wet cycles.PDMS-modified geopolymer concrete is found to exhibit long-term waterproof performance that is not weakened by dry-wet cycles.This is attributed to the robust combination of organic components and the geopolymer gel skeleton formed through phase cross-linking.Meanwhile,PDMS-modified geopolymer concrete’s hydrophobicity,strength,and microstructure are essentially unaffected.In contrast,SMS-modified geopolymer concrete shows higher water sensitivity,although it does maintain efficient waterproof performance.Due to relatively low binding energy,the dry-wet cycles may lead to the detachment of some SMS molecules from the gel network,which results in a decrease of 18.6%in compressive strength and an increase of 37.6%in total porosity.This work confirms the utility of hydrophobically-modified geopolymer concrete as a building material for long-term service in wet environments,for instance,areas with frequent precipitation,or splash and tidal zones.展开更多
Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the ...Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.展开更多
Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the pro...Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the proportioning of such materials.However,these studies lack the relationship between the impermeability pressure of mortar and the components,and the mechanism of action is somewhat debatable.Therefore,we adopted a two-step method in our experiments.Firstly,we screened out the components that significantly impact impermeability from a variety of active components by orthogonal test.We then optimized the design of the active group ratio using the simplex lattice method.Lastly,we conducted a performance test of the optimal ratio and explored the waterproofing mechanism of homemade CCCW.展开更多
Prefabricated green buildings are becoming a trend in the construction industry of China.The prefabricated components are made using modern technologies like green materials,artificial intelligence,and low-carbon and ...Prefabricated green buildings are becoming a trend in the construction industry of China.The prefabricated components are made using modern technologies like green materials,artificial intelligence,and low-carbon and energy-saving techniques.This makes them an important aspect of the development of the construction industry in China,representing modernization and sustainable development.This article presents a study on the innovative design of prefabricated green buildings.This article serves to promote sustainable development on a macro level.展开更多
Through the shear tests on composite specimens using four different kinds of tack coat material （epoxy resin, SBS modified emulsified asphalt, SBS modified asphalt and H# bridge waterproof material）, the bond condit...Through the shear tests on composite specimens using four different kinds of tack coat material （epoxy resin, SBS modified emulsified asphalt, SBS modified asphalt and H# bridge waterproof material）, the bond condition between layers of porous asphalt pavement under traffic load, temperature variation and moisture situation is evaluated. The test results show that the bond strength decreases with the rise in temperature, and the relationship between shear strength and temperature can be expressed by a logarithm curve at a high reliability. Under the action of traffic load, the value of shear strength of the mixture right under the centre of the wheel track is smaller than that of other parts of the pavement. It is also found that some effects concerning moisture have comparative effects on the bonding of the two layers. Given all the results achieved during the study, it will be quite rewarding to make rational comparisons during selecting the sound type of tack coat.展开更多
The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of ce...The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.展开更多
The use of concrete wastes in asphalt treated base (ATB) not only prevents environmental pollution but also protect stone resources. But the strength of the concrete wastes is often weaker than nature aggregates and t...The use of concrete wastes in asphalt treated base (ATB) not only prevents environmental pollution but also protect stone resources. But the strength of the concrete wastes is often weaker than nature aggregates and the binding properties with asphalt is poor. So it difficult to meet the requirements of asphalt treated base. In this paper,The organosilicone waterproofing material is used to improve the performance of concrete wastes and the long term immersing frozen-thaw cycle test were used to investigate the anti-stripping performance of limestone asphalt mixture,concrete wastes asphalt mixture and concrete wastes asphalt mixture having treated by organosilicone waterproofing material. The experimental results show that organosilicone waterproofing material can improve the water stability of asphalt mixture. The use of concrete wastes in ATB is achievable.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFC3800905)the National Natural Science Foundation of China(Nos.52238010,52090082,and 52108381)+2 种基金the Shanghai Science and Technology Committee Program(Nos.22XD1430200,23DZ1202806,and 21DZ1200601)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.2023QNRC001)the Fundamental Research Funds for the Central Universities,China.
文摘When subjected to external loads from the ground and nearby construction,tunnel segmental lining joints are prone to damaging deformation.This can result in water leakage into tunnels,posing great safety risks.With this issue in mind,we conducted a series of full-scale tests to study the effects of external loads on the waterproofing performance of longitudinal joints.A customized rig for testing segmental joints was developed to assess the effect of loading magnitude,eccentricity,and loading-unloading-reloading cycles on waterproofing performance.Additionally,the relationship between joint force,sealing gasket deformation,and waterproofing pressure was investigated.The results indicate that:(1)the sealing gasket’s compression rapidly decreases as external loads increase,which weakens the waterproofing capacity of the joint;(2)the watertightness limit dramatically decreases as the bending moment increases;(3)a loading-unloading-reloading cycle leads to degradation of the joint’s waterproofing performance.The findings of this study provide a reference for subsequent waterproofing design of segmental tunnel joints,helping ensure the safety of tunnels throughout their operational lifespans.
文摘The waterproof construction of subway tunnels is a crucial and challenging aspect of subway tunnel engineering.Mastering excellent waterproof construction technology is essential to ensure that the construction meets design requirements and guarantees the safe operation of subway lines.This paper focuses on discussing waterproof construction technology for subway station tunnels.By analyzing the main methods and techniques of underground tunnel construction,as well as the key techniques and difficulties of waterproofing construction,this paper examines the waterproofing construction project of Guangzhou Metro Culture Park Station as a case study.It analyzes the methods,quality management practices,and safety management strategies applied in the project.This paper serves as a reference for tunnel engineering design and construction units in our country,offering insights into effective waterproof construction techniques for subway tunnels.
基金supported by the National Basic Research Program of China (973 Program,Grant No. 2010CB732104)the Fundamental Research Funds for the Central Universities (Grant No. 2011JBM133)
文摘As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environments. In recent years, with the development of undersea tunnel construction, the design and construction technologies have been greatly enhanced. The first undersea tunnel in China has just been built. Waterproofing is the key technique of undersea tunneling. A new concept of waterproofing scheme of grouting, sealing, draining and divided sections was adopted in the construction of the tunnel based on the researches, the in-situ geological features, the astuteness of the current technology and the cost of construction. The structural details of the sealing and draining system are introduced to illustrate the salient features of the new waterproofing technique. It is hoped that experiences described in the paper can offer guidance for the construction of the extensive undersea tunnels in the coming years.
文摘The modified petroleum resin emulsion prepared from the C9petroleum resin was modified with maleic anhydride.The effects of maleic rosin and maleic anhydride addition level,the modification time and the alkali liquor on the properties of the emulsion were discussed.The results showed that the optimum process conditions covered:a maleic anhydride mass fraction of 1.5%,a maleic rosin mass fraction of 10%,a KOH mass fraction of 1%,a petroleum resin modification temperature of 200℃,a petroleum resin modification duration of 3 h,and a modified petroleum resin emulsion/wax emulsion mixing ratio of 1:1.The particle size of modified petroleum resin emulsion prepared under these conditions was equal to 104.166μm.
文摘Polyurethane dispersions (PUD) have diversified into a myriad of applications over the years. This has led to extensive research on both industrial and laboratory fronts as polyurethane dispersions provide liberty to interplay at the molecular level to diversify the properties of the product which has also led to the development of eco-friendly waterborne dispersions. Yet, waterborne PUDs are limited in their mechanical and physical properties as compared to solvent-based products. The incorporation of crosslinkers in the PUD further bolsters these properties thus improving water and solvent resistance. The incorporation of silanols increases solvent resistance and adhesion of the resultant PUD. In this work, a post crosslinking system based on the ketone-hydrazine mechanism was incorporated into the PUD thus providing the required structural reinforcement for construction application. The targeted application for this work is the use of PUDs for waterproofing.
文摘To address the need for producing a cheap,single-component,hot-applied compound joint sealant with high quality for sealing joints and cracks in concrete and flexible pavements without using primer for installation,a hot-applied modified asphalt sealant was produced by blending up about 30% starch into 20% citric acid.The starch and the asphalt cement were mixed at a temperature of above 160 ℃.Thus the waterproofing asphalt was manufactured to protect the surface of various shapes and types from water leakage using the citric acid.Results indicate that this sealant complies with the requirements of ASTM D-1191,D-6690-06a and D-7116-05.The citric acid is a kind of reliable materials for asphalt cement,which can be widely used in paving and waterproofing construction materials,and this offers profound engineering and economic advantages.
文摘In the construction of civil engineering projects, the application of roofing waterproof technology is a key construction content that should be paid attention to based on the safety and convenience of the application of building construction after the completion of the basic frame construction of the building entity and the core project of the entity part construction. In the concrete implementation of roofing waterproof construction, professional technology needs to be applied, and the application of waterproof technology should be assisted to achieve good waterproof effect in combination with the construction technology requirements of each link of roofing. Specifically, in civil engineering projects, the application of roofing waterproof technology needs to find targeted waterproof technology in combination with different building entity areas. In addition, the quality control of raw materials in waterproof construction, construction of waterproof layer, design and construction of drainage system may affect the application effect of waterproof construction technology. Based on this, it is necessary for construction personnel and management personnel to guarantee the effective application of waterproof technology from the aspects of raw material construction technology and construction management.
文摘At present, the height of the building is increasing, and the depth of the foundation is also increasing. All construction units are also increasing their efforts to develop underground space. The basement is the basic part of the building structure system, and its waterproof performance must be guaranteed, otherwise it will threaten the stability of the basement and even the whole building. It is particularly important to control the construction quality of basement waterproofing works, which can not only provide security for peoples daily use of basements, but also promote the long-term development of Chinas construction industry. Based on this, this paper explores the quality measures of basement waterproofing construction in high-rise building projects.
基金supported by the Fundamental Research Funds for the Central Universities of Central South University(No.2023ZZTS0183)the Fundamental Research Funds for the Central Universities(No.502802002).
文摘Double-bonded spray membrane waterproofing materials have excellent waterproofing performance and can improve the load-bearing capacity of tunnel linings,leading to an increasing global application.However,due to the double-bonded capability of spray membrane materials,traditional interlayer drainage methods cannot be applied.This limitation makes it difficult to use them in drainage-type tunnels,significantly restricting their range of applications.In this regard,a novel tunnel waterproof-drainage system based on double-bonded spray membrane materials was proposed in this paper.The proposed drainage system primarily comprises upper drainage sheets and bottom drainage blind pipes,both located in the tunnel circumferential direction,as well as longitudinal drainage pipes within the tunnel.Subsequently,numerical calculation methods are employed to analyze the seepage characteristics of this system,revealing the water pressure distribution around the tunnel.The results indicate that in the novel waterproof-drainage system,the water pressure in the secondary lining exhibits a“mushroom-shaped”distribution in the circumferential direction,while the water pressure in the longitudinal direction exhibits a“wave-like”distribution.Furthermore,comparative results with other waterproof-drainage systems indicate that under typical working conditions with a water head of 160 m and a rock permeability coefficient of 10^(−6)m/s,the maximum water pressure in the secondary lining of the novel waterproof-drainage system is 0.6 MPa.This represents a significant reduction compared to fully encapsulated waterproofing and traditional drainage systems,which respectively reduce the water pressure by 65%and 30%.The applicability analysis of the double-bonded waterproofing and drainage system reveals that it can reduce at least 40%of the static water pressure in any groundwater environments.The novel drainage system provides a valuable reference for the application of double-bonded spray membrane waterproofing materials in drainage-type tunnels.
基金supported by the National Natural Science Foundation of China(Nos.52308300,52370025,52108266).
文摘The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-organic frameworks(MOFs),the multifunctional environment remediation materials,to be applied in heritage environmental protection.The advantages of MOFs lie in their multifunction like adsorption,photocatalysis,sterilization,as well as the controllable structure and properties that could be flexibly adjusted as demands,helping the heritage against various environmental threats.Thereby,the applications and the corresponding mechanisms of MOFs in cultural heritage preservation were reviewed in this work,including harmful gas adsorption,surface waterproofing,particulate matters(PM)removal,anti-bacterial and humidity control of environment.Finally,the selection principles and precautions of MOFs in heritage preservation were discussed,aiming to provide a forward-looking direction for the selection and application of MOFs.
文摘Purpose–Salt rock from salt lakes can serve as a cost-effective material for subgrade filling,as demonstrated in projects like the Qarhan Salt Lake section of the Qinghai-Tibet Railway and the Qarhan Salt Lake section of the G215 Highway.This state-of-the-art paper aims to summarize the engineering properties of salt rock filling and present the advances of its utilization.Design/methodology/approach–This paper collects and analyzes laboratory and field data of salt rock filling from previous studies to present a comprehensive analysis of the engineering properties and utilization of salt rock fillings.Findings–Salt rock primarily contains minerals such as halite and glauberite,which contribute to its unique phase-changing behavior under varying environmental conditions,impacting its mechanical properties.Salt rock filling shrinks when in contact with vapor or unsaturated brine and expands under cooling or evaporation.Its use is particularly recommended for arid regions,with specific restrictions depending on the structure type.This paper discusses suggested countermeasures to mitigate these issues,as well as key quality acceptance indices for salt rock filling compaction.Moisture content after air-drying is recommended as a crucial parameter for construction quality control.Originality/value–This review aims to support future research and engineering practices in salt rock subgrade applications.
基金financially supported by National Natural Science Foundation of China(52090083)Shanghai Committee of Science and Technology(20DZ1202600)China Railway Southern Investment Group Co.Ltd(Project No.ZTNF-2020-1).
文摘The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof performance for certain tunnels with high water pressure,especially water-conveyance tunnels.This paper presents a series of waterproofing tests on joints with different settings of double gaskets via an improved test apparatus.Four cases are investigated,including(i)double gaskets with equal high/low waterproof capacity,(ii)the outer gasket with higher waterproof capacity,and(iii)the outer gasket with lower waterproof capacity.Different joint openings are also considered.Moreover,the water pressures at two cavities are continuously monitored to highlight the waterproofing mechanism and failure pattern of double gaskets.The results demonstrate that the gasket with the higher waterproofing capacity dominates the overall waterproofing capacity of joint with double gaskets;only a little enhancement of the waterproofing capacity is found for the joint with the same double gaskets.The waterproofing capacity of joints with double gaskets decreases with the increase of the joint opening.The failure pattern depends on the arrangement of double gaskets,and four stages can be identified during the whole failure process.The advantages of double gaskets in case of joint rotation are also discussed.
文摘Establish an efficacy evaluation method for foundation products in vivo and vitro.The hiding power,whiteness,waterproof and anti-sweat effect were evaluated in vitro test,where CR ratio,Individual Type Angle (ITA°) and chromatic aberration (E) were measured as evaluation indicators by standard black/white cardboard,artificial leather and artificial sweat.In clinical assessment,the anti-stain,waterproof,anti-sweat effect of the foundation products were evaluated through the ΔE change,before and after the treatment of products by staining,wetting,sweating in forearm skin.There were significant differences in CR ratio of different types of samples on standard black and white cardboards (P<0.05),ITA° of artificial leather has a significant increase after treatment (P<0.05),?E﹤1.5 in black cloth after dipping test,while ΔE﹤1.5 in leather after water and artificial sweat treatment.Clinical assessment showed that ?E ﹤50%,which had no significant difference in human skin color,before and after the test (P>0.05).The change trend of efficacy evaluation in vitro test was basically consistent with that of visual evaluation and clinical assessment,indicated that the efficacy evaluation methods of foundation products in vivo and vitro are intuitive,quantifiable,and can be used to evaluate the efficacy of foundation products.
基金supported by the National Natural Science Foundation of China(Nos.52101328 and 52171277)the National Key Research and Development Program of China(No.2022YFE0109200)+1 种基金the Foundation of the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SZ-TD006)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(No.GZB20230653)。
文摘The waterproof performance,mechanical properties,chemical composition,microstructure,and pore structure of hydrophobically-modified geopolymer concrete are investigated before and after dry-wet cycles,to determine the long-term feasibility of using hydrophobically-modified geopolymer concrete in wet environments.We use two types of organic modifying agents:polydimethylsiloxane(PDMS)and sodium methyl siliconate(SMS).The experimental results show that incorporating 2%–6%PDMS or 5%–15%SMS can make the concrete hydrophobic,with water absorption and chloride transport rates decreasing by up to 94.3%.We also analyze the bonding modes of organic molecules and geopolymer gels,as well as their evolution mechanisms during dry-wet cycles.PDMS-modified geopolymer concrete is found to exhibit long-term waterproof performance that is not weakened by dry-wet cycles.This is attributed to the robust combination of organic components and the geopolymer gel skeleton formed through phase cross-linking.Meanwhile,PDMS-modified geopolymer concrete’s hydrophobicity,strength,and microstructure are essentially unaffected.In contrast,SMS-modified geopolymer concrete shows higher water sensitivity,although it does maintain efficient waterproof performance.Due to relatively low binding energy,the dry-wet cycles may lead to the detachment of some SMS molecules from the gel network,which results in a decrease of 18.6%in compressive strength and an increase of 37.6%in total porosity.This work confirms the utility of hydrophobically-modified geopolymer concrete as a building material for long-term service in wet environments,for instance,areas with frequent precipitation,or splash and tidal zones.
基金jointly funded by the guangxi Science and Technology Base and Talent Project(AD23026104)the Key Research and Development Program Project in Guangxi(AB23026121)。
文摘Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.
文摘Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the proportioning of such materials.However,these studies lack the relationship between the impermeability pressure of mortar and the components,and the mechanism of action is somewhat debatable.Therefore,we adopted a two-step method in our experiments.Firstly,we screened out the components that significantly impact impermeability from a variety of active components by orthogonal test.We then optimized the design of the active group ratio using the simplex lattice method.Lastly,we conducted a performance test of the optimal ratio and explored the waterproofing mechanism of homemade CCCW.
文摘Prefabricated green buildings are becoming a trend in the construction industry of China.The prefabricated components are made using modern technologies like green materials,artificial intelligence,and low-carbon and energy-saving techniques.This makes them an important aspect of the development of the construction industry in China,representing modernization and sustainable development.This article presents a study on the innovative design of prefabricated green buildings.This article serves to promote sustainable development on a macro level.
文摘Through the shear tests on composite specimens using four different kinds of tack coat material （epoxy resin, SBS modified emulsified asphalt, SBS modified asphalt and H# bridge waterproof material）, the bond condition between layers of porous asphalt pavement under traffic load, temperature variation and moisture situation is evaluated. The test results show that the bond strength decreases with the rise in temperature, and the relationship between shear strength and temperature can be expressed by a logarithm curve at a high reliability. Under the action of traffic load, the value of shear strength of the mixture right under the centre of the wheel track is smaller than that of other parts of the pavement. It is also found that some effects concerning moisture have comparative effects on the bonding of the two layers. Given all the results achieved during the study, it will be quite rewarding to make rational comparisons during selecting the sound type of tack coat.
基金Funded by the National Natural Science Foundation of China(No.50878170 and No. 10672128)
文摘The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.
文摘The use of concrete wastes in asphalt treated base (ATB) not only prevents environmental pollution but also protect stone resources. But the strength of the concrete wastes is often weaker than nature aggregates and the binding properties with asphalt is poor. So it difficult to meet the requirements of asphalt treated base. In this paper,The organosilicone waterproofing material is used to improve the performance of concrete wastes and the long term immersing frozen-thaw cycle test were used to investigate the anti-stripping performance of limestone asphalt mixture,concrete wastes asphalt mixture and concrete wastes asphalt mixture having treated by organosilicone waterproofing material. The experimental results show that organosilicone waterproofing material can improve the water stability of asphalt mixture. The use of concrete wastes in ATB is achievable.
