Materials
·
2022
·Vol. 15
·期 21
·7492
·
IF 3.748
Min Qiao,Jingzhi Wu,Nanxiao Gao,Guangcheng Shan,Fei Shen,Jian Chen,Bosong Zhu
In this study, a series of polyether-type defoamers for concrete which consist of the same alkyl chain (hydrophobic part) but different polyether chains (hydrophilic part) was prepared, and the structure–property relationship of the defoamers was investigated for the first time. Using oleyl alcohol (OA) as the starting agent (alkyl chain), the polyether defoamers with different polyether chains were prepared by changing the amount and sequence of ethylene oxide (EO) and propylene oxide (PO) units. The properties of different defoamers were tested in aqueous solutions, and fresh and hardened mortars; the structure–property relationship of the defoamers was thus studied. The results indicated that the defoaming capacity of the polyether defoamers decreased with an increased EO amount, and the defoamers linked with both EO and PO units (PO before EO) had a stronger defoaming capacity than those linked with EO only. This study is beneficial for the development and applications of novel synthetic polyether-type defoamers for concrete.Keywords:polyether;defoamer;bubble;air void;mortar;concrete
研究领域:
建筑材料学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 4
·1620
·
IF 3.4
Yihong Zhang,Yong Wu,Puyu Zhou,Zhiyuan Song,Yayun Jia,Weiyi Ouyang,Rafael Luque,Yang Sun
Aluminum sulfate was employed as the main accelerator in order to explore new non-chloride and alkali-free cement accelerators. Acrylic acid, aluminum fluoride, or alkanolamine were used as regulators to further accelerate cement setting. The setting time, compressive, and flexural strengths in cement early strength progress were detected, and both the cement (raw material) and hydrated mortar were fully characterized. The cement setting experiments revealed that only loading acrylic acid as the regulator would decrease the setting time of cement and increase the compressive and flexural strengths of mortar, but further introduction of aluminum fluoride or alkanolamine improved this process drastically. In the meantime, structural characterizations indicated that the raw material (cement) used in this work was composed of C3S (alite), while hydrated mortar consisted of quartz and C3A (tricalcium aluminate). During this transformation, the coordination polyhedron of Al3+was changed from a tetrahedron to octahedron. This work puts forward a significant strategy for promoting the activity of aluminum sulfate in cement setting and would contribute to the future design of new non-chloride and alkali-free cement accelerators.Keywords:aluminum sulfate;accelerator;setting time;mortar;strength
研究领域:
材料科学
·
土木工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Peng Zhou,ZhengYu Zhu,Wei She
Superhydrophobic cement-based materials are promising candidates to alleviate the performance deterioration of concrete constructions caused by water penetration. However, the weak mechanical performance of superhydrophobic surfaces, and severe reduction in compressive strength due to bulk modification, present significant challenges for the application of superhydrophobic cement-based materials. In this work, a superhydrophobic mortar (S-mortar) was prepared using a facile and economical method by surface micro-nano roughness construction and matrix silane modification, and nano-silica was introduced to compensate for the strength loss. The obtained S-mortar exhibits superb surface mechanical durability and chemical stability, no significant decrease in superhydrophobic property after sandpaper rubbing, knife scratches, and exposure to extreme temperatures, while even new surfaces exposed by cutting and powders obtained by grinding possess excellent water repellency. Furthermore, the superhydrophobicity endows the S-mortar with self-cleaning, anti-fouling, anti-icing, anti-freezing, and anti-corrosion properties. This approach creates a balance between superhydrophobic property and mechanical performance, broadening application prospects of superhydrophobic cement-based materials.
研究领域:
材料科学
·
建筑工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
·
2024
·
IF 6.7
Zhi Li,Shengjie Yao,Guichao Wang,Chuangang Fan,Xiaoxu Wu
This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar. This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar, with a special focus on optimizing the composition to enhance mechanical properties. The parametric range explored included phosphogypsum content from 10 to 30 wt%, hollow glass microspheres (HGS) from 5 to 15 wt%, and aerogel slurry from 40 to 80 wt%. Our findings reveal that the optimal composition, which provided the best balance between thermal insulation and mechanical strength, consisted of 20 wt% phosphogypsum, 10 wt% HGS, and 60 wt% aerogel slurry. Notably, the introduction of 0.14 % hydroxypropyl methylcellulose (HPMC) and 1.89 % re-dispersible polymer powder (RPP) significantly enhanced the compressive strength of the mortars. Specifically, compressive strength increased from an initial 0.05 MPa–0.27 MPa post-enhancement with HPMC and RPP. This research provides a detailed understanding of how individual components influence the formulation of APG and offers insights for optimizing the overall performance of aerogel-phosphogypsum composites, contributing to advancements in sustainable building materials.
研究领域:
建筑材料
·
可持续发展
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Juncheng Wen,Yan Wan,Yingzi Yang
Most durability issues in cement-based materials stem from water intrusion, which can be mitigated by hydrophobic materials with excellent waterproofing properties. This study proposes a green wet chemical method using stearic acid (SA) and waste glass powder (WGP) to synthesize hydrophobic WGP (HWGP). The effect of SA dosage on the water contact angle of HWGP was investigated, and the optimal SA dosage for preparing HWGP was determined through TG analysis. XRD, FTIR, XPS, and TEM tests revealed the synthesis mechanism of HWGP. The effects of HWGP on mortar's mechanical properties, water and frost resistance were also studied, and the optimal dosage of HWGP for preparing hydrophobic mortar was determined. The results show that 8 % SA is optimal for preparing HWGP, and its water contact angle is 132.2°. The synthesis occurs through reactions between SA and Na + , Ca 2+ , and Si-OH groups, with the long carbon chains of SA grafted onto WGP, forming a hydrophobic layer about 4 nm thick. As HWGP content increases, compressive strength initially increases and then decreases, while water and frost resistance improve significantly. The optimal dosage for preparing hydrophobic mortar is 15 % HWGP, where compressive strength decreases by only 6.9 %, flexural strength increases by 12.5 %, and water contact angle increases by 91.2°. Additionally, initial and secondary water absorption rates decrease by 79.4 % and 92.2 %, respectively, total water absorption amount over 8d decreases by 64.9 %, and frost resistance improves by 70.9 %.
研究领域:
建筑材料
·
化学工程
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Xianshu Gao,Pengfei Tang,Tao Gu,Jia Zhuang,Hongping Zhang
Introducing uniform, stable, and small pores by adding air-entraining agents (AEAs) is an effective strategy for improving the freeze–thaw resistance and workability of cement concrete materials. In this study, the gelatin with hydrophobic and hydrophilic functional groups was used as an AEA for cement concrete materials and systematically studied its effect on the performance of cement mortar specimens. The results showed that gelatin has a surfactant-like function and can effectively reduce the surface tension of the gas–liquid interface. In an alkaline environment, Ca 2+ ions in cement pore solution chelate with carboxylate ions formed by carboxyl ionization, further enhancing the performance of gelatin-based AEAs. Thanks to the reduction in surface activity and carboxyl ionization, introducing gelatin increased the porosity of cement mortar specimens from 0.53% to 2.69%. Furthermore, introducing an appropriate amount (>0.1 wt%) of gelatin does not significantly impact the workability or mechanical properties of cement mortar. Based on these characteristics, gelatin has potential as an AEA for cement concrete materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Ming Sun,Congtao Sun,Peng Zhang,Nazhen Liu,Yantao Li,Jizhou Duan,Baorong Hou
This study investigated the effects of carbonation on the chloride binding of mortars containing simulated marine sand. Various admixtures were added, and metakaolin (MK), fly ash (FA), nano-Al 2 O 3 (NA), and aluminum (A) were considered as supplementary cementitious materials (SCMs) for use in mortars. Changes in free chloride content, total chloride content, bound chloride content, chloride binding rates, and pH values as a function of mortar depth were analyzed, and the effects of carbonation on the hydration products were also assessed. The results indicated that in the place of cement, SCMs could significantly increase the carbonation zone depth in mortar. The chloride ions migrated outward and inward under accelerated carbonation conditions in the mortar, generating two peak values for the chloride content in the mortars. Consequently, the incorporation of SCMs was beneficial for chloride ion migration in mortars under carbonation. Additionally, the bound chloride content and chloride binding rates were initially extremely low, then gradually increased, and finally stabilized with increased depth in the mortars under carbonation. Furthermore, the incorporation of SCMs resulted in the decreased chloride binding capacity of the mortars under accelerated carbonation, and Friedel’s salt gradually decomposed with carbonation.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2019
·
IF 4.046
Yamei Cai,Dongxing Xuan,Chi Sun Poon
Swelling caused by alkali-silica reaction (ASR) in concrete is a deleterious behavior due to reactions between alkaline pore solution and amorphous or metastable forms of silica in aggregates. Generally, mitigation by using pozzolanic materials is commonly adopted. This study compared the effectiveness of a highly-reactive nano-SiO 2 (NS) and a slowly-reactive waste glass powder (WGP) on mitigating ASR of cement mortars prepared with crushed glass cullet as aggregates. The experimental results showed that incorporating 2% NS or 10% WGP or a hybrid of the two in the mortar can decrease the ASR expansion. Using WGP resulted in larger reduction in the ASR expansion than using NS. Meanwhile, there was an improvement of strength from 7 d to 28 d for the mortar prepared with WGP. The composition of reaction products containing the ASR gel formed in a simulated ASR condition and the macro-/micro-structure of the tested mortars were further analyzed. It was found that the reaction products formed with high ratios of Na/Si and Ca/Si were favorable in mitigating the ASR expansion. For the specimen prepared with WGP, the increase in the ratio of Ca/Si would increase the stiffness of the ASR gel, and a higher Na/Si ratio would help reduce the osmotic pressure. The findings from this study would be useful for the selection of pozzolans to mitigate the ASR effect when using crushed glass cullet as aggregates in cement mortars.
研究领域:
材料科学
·
土木工程
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Fei Shen,Jian Chen,Min Qiao,Guangcheng Shan,Nanxiao Gao,Qingyong Wu,Qianping Ran,Jianzhong Liu,Fangyu Han,Bing Han,Wentong Gao
The development of air bubbles determines the quality of air-void structure and the durability of concrete. Recently, air bubbles stabilized by nanoparticles has received considerable attention for the improvement of air-void structure in cement mortar . However, the relationship between particle properties and the resulting bubbles quality and stability remains unclear. In this study, the SiO 2 particles with different wettability , sizes and charge types were obtained by chemical modification. These modified SiO 2 particles were added to the solutions and cement mortars and the prepared mixtures were characterized for the evolution and structure of the entrained bubbles. The influence mechanism of particle properties on the bubbles in solutions and cement mortars was also investigated. The experimental results show that the particles with intermediate wettability (60° ≤ θ ≤ 110°) and smaller sizes (around 50 nm) decreased the time-dependent changes of air contents, meanwhile induced smaller bubble size in both solution and mortars. Since most of the air-entraining agents were charged surfactants , which have electrostatic attraction interactions with oppositely charged SiO 2 particles, thus the addition of oppositely charged SiO 2 particles further inhibit the loss of air contents within 2 h. The analysis of granule structure around bubbles reveals that the particles with suitable structures tend to strongly absorb on both the surface and interlayer of bubbles as aggregates, forming a rigid and incompressible grid structure to prevent the Ostwald ripening of bubbles.
研究领域:
材料科学
·
胶体化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS AND STRUCTURES
·
2024
·Vol. 57
·期 5
·1-12
·
IF 3.4
Zhang Wan,Wu Zhihong,Huang Wang,Liu Jiayuan,Zhou Huafeng,Qiu Junlong
It is insufficient to enhance the strength of shotcrete by simply relying on the early strength component aluminum sulfate in the liquid accelerator. The introduction of organic additives can effectively compensate for this deficiency. In this study, three different structures of organic ethers, 18-crown-6 (ECS), tetraethylene glycol monomethyl ether (Tg), and ethylene glycol monomethyl ether (Eg), were added to an aluminum sulfate alkali-free liquid accelerator, and their effects were comprehensively investigated. The results revealed that these organic ethers were capable of bolstering the strength of the mortar after 28 d. The efficiency of these ether organics on the strength of cement mixed with the accelerator followed the order: ECS > Tg > Eg. Specifically, when the ECS content reached 0.3%, the compressive strength of the mortar at 1 d was measured at 8.07 MPa. In addition, changes in the phase composition and micromorphology were scrutinized through X-ray diffraction and scanning electron microscopy, culminating in the establishment of a mechanistic model elucidating the hydration process of organic ether accelerator cement.
研究领域:
建筑材料学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Chengbin Wang,Bin Wang,Xinghua Su,Rui He
Due to the excellent strength, ultra-high specific surface area and extremely small size of graphene, it is an ideal modification component for cementitious materials. However, the conventional production methods of graphene are often time-consuming, energy-intensive, and expensive, which limits its development in cementitious materials to a certain extent. Recently, flash joule heating (FJH) has been shown to be an effective and green method to synthesize graphene. Therefore, the present paper attempts to prepare graphene from waste rubber powder by FJH and study its effect on the properties of cementitious materials. The results demonstrate that the study successfully converted waste rubber powder into multilayer graphene with minimal defects. Raman spectroscopy and XRD analyses revealed characteristic peaks of graphene, while the results of TGA show that graphene have excellent thermal stability. XPS analysis indicate that the purity of graphene can reach about 87.33 %. SEM and TEM reveal its multi-layered lamellar structure. Moreover, we synthesized graphene-enhanced cement mortar, which exhibited improved mechanical properties. The pore structure was optimized, with decreased porosity and mean pore size. Microscopically, the presence of graphene led to a denser arrangement of hydration products, fewer pores, and cracks. AFM results demonstrated that graphene effectively enhanced the average elastic modulus at the nanoscale interface. This study contributes to the advancement of sustainable development by recycling waste rubber and proving the potential of graphene in cement composites.
研究领域:
材料科学
·
可持续发展
·
土木工程
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2020
·
IF 7.246
Chun Pei,Ji-Hua Zhu,Feng Xing
Titanium dioxide (TiO 2 ) photocatalyst coatings on cement material surfaces of buildings or structures that require high mechanical integrity, such as tunnel walls and pedestrian roads, can directly utilize solar energy for self-cleaning surfaces and removing air pollutants in the environment. However, TiO 2 can utilize only ultraviolet (UV) light, which accounts for only 5% of sunlight. To improve photocatalytic efficiency, graphene/TiO 2 nanocomposites are prepared by a sol-gel assisted electrospray method and characterized by various instrumental analysis methods. Photocatalytic cement mortars are prepared by incorporating the as-prepared nanocomposites and commercial TiO 2 into cement mortar. The self-cleaning and air purifying properties of the cement mortars are evaluated by the discoloration of rhodamine B (RhB) and the removal of nitric oxide (NO). As desired, cement mortar coated with graphene/TiO 2 nanocomposites expresses high photocatalytic effectiveness on both RhB and NO. In addition, the regeneration of graphene/TiO 2 nanocomposite photocatalysts has also been studied. The results show that the photocatalytic activity can be effectively regenerated by UV irradiation, with good repeatability and stability. Therefore, graphene/TiO 2 -coated cement mortar is a potential candidate for effective building self-cleaning and air purification through the use of solar irradiation .
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）