自愈性超疏水材料在金属防护上的应用进展

超疏水表面是一种具有特殊表面性质的新型材料,具有防水、防雾、防雪、防污染、抗氧化、防腐蚀和自清洁以及防止电流传导等重要特点。该种材料因为其微纳米级粗糙结构和低表面能性质开始用于金属防护,能够大大减少腐蚀介质与表面的接触面积,有效地增大腐蚀粒子侵入基体表面的阻力。首先对超疏水表面的3种主流理论模型进行介绍,然后从不同角度综述了不同修复机理下超疏水材料的自愈方式;重点对当超疏水表面受到物理或化学破坏时,微胶囊型、高聚物型和负载缓蚀剂型的自我修复机理进行说明,并介绍了不同超疏水材料在金属防护中的应用;最后指出了自愈性智能型超疏水涂料的发展方向。

微波吸收路面改性沥青混合料加热自愈特征研究

为研究新型路面改性沥青混合料在微波吸收条件下的自愈特性与修复效果,开展了室内不同类型改性沥青混合料的室内加热试验、弯曲循环试验及弯曲疲劳试验。试验结果表明:(1)粗、细改性玄武岩沥青混合料(MCAM、MCFM)工程性能更加优良,其弯曲强度较玄武岩沥青混合料(BAM)分别高出11.76%、8.82%;(2)三种不同类型沥青混合料微波处理后表面温度、内部温度与处理时间之间均成线性相关,但微波处理后改性玄武岩沥青混合料的温度均高于玄武岩沥青混合料,因此微波处理后改性玄武岩沥青混合料的弯曲强度修复效果高于玄武岩沥青混合料;(3)初始状态的MCAM和MCFM沥青混合料的弯曲疲劳寿命较BAM高,微波修复处理条件下不同类型沥青混合料弯曲疲劳寿命均高于自然修复处理方式,且改性混合料修复效果更佳。

装配式建筑混凝土裂缝控制技术研究与应用

本研究深入探讨了装配式建筑混凝土裂缝控制技术,通过工程案例分析裂缝成因和分类,并提出一系列防裂与修补措施。研究发现,优化混凝土配比、选择高性能材料和加强养护可有效预防裂缝产生。采用新型材料如高性能纤维和增强剂进行混凝土改性,显著提高了其抗裂性能。利用声发射和数字图像技术监测裂缝,结合自愈材料实现自动修复,为装配式建筑混凝土裂缝控制与修补提供了创新策略。本研究对提升装配式建筑工程质量和安全性具有重要意义。

行业信息

炭纤维合成材料新应用最近,一座跨度为110 m、中间没有其他支撑的混合式桥梁在法国胡安市建成。这座桥梁的牵拉索创新性采用了炭纤维合成材料。承揽此项目的法国万喜集团(Groupe Vinci)和弗莱西奈公司(Freyssinet)希望通过这一项目证实这种新材料的长期性能,并计划将其应用于石油开采业,使用炭纤维缆绳替代传统上用以锚固采油平台的钢管。

建筑工程施工中混凝土裂缝防治技术研究

随着社会经济的飞速发展,建筑工程的规模越来越大,混凝土作为建筑工程中的主要材料,其质量对建筑的稳定性一直起着至关重要的作用。然而在实际施工中,混凝土裂缝的出现已成为制约建筑工程质量提升的主要难题。为了解决这一问题,该文以建筑工程施工中混凝土裂缝为研究对象,对混凝土产生裂缝的主要机理、裂缝的分类、防治技术以及更为具有发展前景的新型防治技术进行了深入的研究和探讨。研究发现,热量变化、内部应力、外施荷载是主要原因,其中早期裂缝防治应当关注混凝土浇筑工艺,实行确保混凝土水泥比例适宜和温度控制,混凝土裂缝的防治主要集中于选择合适的材料、合理的水灰比、正确的施工方式和适宜的养护方式。近年来,裂缝自愈材料的应用也为混凝土裂缝防治提供了新的可能性。通过对比发现自愈材料可在某种程度上减少人为维修及养护的成本和提高工程寿命。本文的研究成果可为实践提供理论和技术支持,有助于建筑技术人员全面理解和解决混凝土裂缝问题。

Effects of superabsorbent polymer particles on flexural properties and self-healing behavior of ECC

In order to improve the self-healing behavior and the recovery of mechanical properties of engineered cementitious composites(ECC),the approach of incorporating superabsorbent polymer(SAP)in mixtures is investigated.The rapid water penetration test and four-point bending test were conducted to evaluate the effects of self-healing on the water permeability and mechanical properties of pre-damaged ECC.The self-healing process and self-healing products were observed by the environment scanning electron microscope(ESEM)and energy dispersive X-ray spectroscopy(EDS).The experimental results show that all ECC mixtures exhibit excellent flexural capacity,meanwhile maintaining a crack width below 50μm.The incorporation of SAP particles in ECC can apparently improve the mechanical recovery of ECC mixtures after 10 healing curing cycles,such as flexural deformation and flexural stiffness.The flexural stiffness of ECC containing 4%SAP particles after self-healing can be recovered to 80%.The self-healing test results show that when the water permeability of ECC mixtures incorporating SAP particles is close to zero,only three healing cycles are needed.When ECC incorpora ting more SAP particles,the accelerated self-healing process can be finished in the first three cycles,and self-healing product is mixed Ca(OH)2/CaCO 3 with CaCO 3 being a major component in the later stage.It is,therefore,feasible to produce ECC materials incorporating SAP particles,while simultaneously maintaining higher material ductility and self-healing behavior.

Permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives

The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.

Design and synthesis of self-healing polymers

Self-healing polymers represent a class of materials with built-in capability of rehabilitating damages. The topic has attracted increasingly more attention in the past few years. The on-going research activities clearly indicate that self-healing polymeric materials turn out to be a typical multi-disciplinary area concerning polymer chemistry, organic synthesis, polymer physics, theoretical and experimental mechanics, processing, composites manufacturing, interfacial engineering, etc. The present article briefly reviews the achievements of the groups worldwide, and particularly the work carried out in our own laboratory towards strength recovery for structural applications. To ensure sufficient coverage, thermoplastics and thermosetting polymers, extrinsic and intrinsic self-healing, autonomic and non-autonomic healing approaches are included. Innovative routes that correlate materials chemistry to full capacity restoration are discussed for further development from bioinspired toward biomimetic repair.