【作者】 吴彻平；

【导师】 彭家惠；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2013， 博士

【摘要】 胶粉聚苯颗粒外墙外保温系统具有保温性、耐候性较好、施工快捷简便、工程造价较低等特点，近年来在节能工程中广泛应用，已成为我国夏热冬冷和夏热冬暖地区主要外墙外保温系统之一。该系统胶粉聚苯颗粒保温砂浆强度较低、吸水率高、耐候性差、收缩应力较高，抗裂层易开裂，系统耐久性、安全性存在一定隐患，系统开裂、渗漏、脱落的质量事故时有发生。研究胶粉聚苯颗粒保温砂浆、抗裂砂浆浆配制及其外保温系统开裂成因与机制，从材料及系统构造着手，改善和提升系统抗裂性对于提高夏热冬冷和夏热冬暖地区胶粉聚苯颗粒保温砂浆及其外保温系统的使用效率和保温效果，具有重要的现实意义和良好的指导作用。为克服原发聚苯乙烯颗粒保温砂浆粘聚性、施工性差的缺陷，系统研究了聚苯颗粒表面改性技术。利用偶联剂和粘接剂的双重作用，采用预处理表面造壳，使聚苯颗粒表面形成亲水性无机薄层，表面由憎水性改变为亲水性，从根本上解决了胶凝材对聚苯颗粒表面不润湿的技术难题，使改善胶凝材与聚苯颗粒基面的结合由粗放式的采用有机粘结剂向聚苯颗粒表面改性方向发展。这一低成本表面改性技术为高性能聚苯颗粒保温砂浆制备奠定了坚实的技术基础。系统研究了聚苯颗粒级配、形貌、聚合物粘结剂、保水剂、聚合物纤维、有机硅防水剂对保温砂浆性能的影响。可再分散乳胶粉可显著改善保温砂浆施工性和粘结性能，并提高硬化体韧性，其适宜掺量为5.0~6.0kg m3；甲基纤维素醚是聚苯颗粒保温砂浆的高效保水剂，但存在水灰比增加，强度降低的负面影响，其适宜掺量为1.5~1.7kg m3；聚丙烯纤维能有效抑制保温砂浆收缩，提高硬化保温砂浆的断裂韧性和抗开裂性，其最佳长度宜控制在8~12mm，适宜掺量为0.7~1.0kg m3；有机硅防水剂可显著降低保温砂浆吸水率，改善其耐水性，其适宜掺量为0.6kg m3。采用聚苯颗粒表面改性，以及聚合物粘结剂增粘增韧、聚丙烯纤维增强、甲基纤维素醚保水、有机硅防水等综合措施，配制了干表观密度230kg m3、导热系数0.056W m k、抗压强度0.8MPa、压剪粘结强度0.117MPa、吸水率2.5%、干缩率0.872‰的保温砂浆，其施工性、强度、耐水性、抗裂性均明显优于传统的高性能聚苯颗粒保温砂浆。抗裂砂浆是胶粉聚苯颗粒外保温系统的重要组成材料。对特细砂抗裂砂浆的配制原理与方法以及砂浆物理力学性能进行了研究。揭示了特细砂含泥量、细度模数对砂浆强度和干缩率的影响规律。通过聚丙烯纤维与木质纤维复合增强、聚合物增韧等措施配制了拉伸粘结强度0.96MPa、裂缝指数1.6、56d收缩率0.565‰、28d冲击能8.7J、28d断裂能300.3J m2、最大变形量3.02mm、抗裂性优良的特细砂抗裂砂浆，对外保温系统特细砂抗裂砂浆制备有很好的指导作用。采用有限元数值模拟分析软件研究了胶粉聚苯颗粒外保温系统在重庆极端高温和极端低温下的应力应变行为。保温层的温度梯度和温度应变最大，通过使用原发聚苯颗粒配制的保温砂浆和在保温层中设置伸缩缝可以有效降低构造层的温度应变，伸缩缝的宽度应不少于8mm，伸缩缝的设置间隔不超过2层或6m。抗裂砂浆层的温度应力最大，且不均匀，开裂风险较大，通过使用特细砂抗裂砂浆可以有效降低构造层的温度应力。窗洞口、阴阳角和女儿墙还出现应力集中现象，窗洞口应力集中区域为洞口四角450方向0.32m0.84m范围，其应力集中大小和范围不随窗洞口大小的变化而变化，阴角应力集中范围为交界处两边各0.05m范围，阳角应力集中范围为交界处两边各0.08m范围，女儿墙应力集中范围为交界处屋面方向0.35m、女儿墙方向0.25m范围，上述区域范围内必须采取玻纤网格布增强措施。论文研制的胶粉聚苯颗粒保温砂浆和特细砂抗裂砂浆进行了工业化生产，产品已在重庆龙湖U城一期4组团多层建筑进行了大规模工程应用。该工程采用35mm原发聚苯颗粒外保温加特细砂抗裂砂浆面层外保温系统，构造上采取每6m设置1030mm水平伸缩缝，窗洞口、阴阳角、女儿墙等应力集中区域采用增强耐碱玻纤网格布增强处理。2012年1月进场，不到2个月即完成该工程外保温施工，同年5月通过了重庆市沙坪坝区建委质量监督站组织的建筑节能专项验收。工程质量获得开发、施工、监理及业内人士一致好评，为成果的推广应用奠定了良好的工程基础。更多还原

【Abstract】 The polystyrene powder has been widely used in the external wall thermalinsulation system due to its super insulation ability，good stability，easy constructionprocess and low cost. The polystyrene powder insulation system is one of the popularinsulation systems in various regions of China with large temperature gap betweensummer and winter. However，there are drawbacks occurring to the polystyrene powder.The polystyrene powders possess low strength，high water absorption，high shrinkstress，easy cracking and safety issue. In addition，the polystyrene powder insulationsystem occasionally cracks，leakages，and chips. In this dissertation，the formation andmechanism of cracking of polystyrene powders and insulation system are investigated.From the material and insulation system points of view，the utilization of polystyrenepowders and the insulation effect of polystyrene powders and insulation system havebeen dramatically improved by preventing the insulation system from cracking.The surface treatment of polystyrene powders has been systematically investigatedto increase the adhesive ability. We use the coupling agents and binding agents to form ahydrophilic shell on the hydrophobic polystyrene powders. The hydrophilic shell on thehydrophobic polystyrene powders increases the adhesion between the polystyrenepowders and cementitious material. The improvement of adhesion by the hydrophilicshell with the cementitious material is one of EPS surface treatment techniques freewith the organic binders. This low cost surface treatment technique guarantees theavailability of polystyrene powder insulation mortar for the mass production.The effect of the graduation and morphology of polystyrene powder，polymerbinders，water retention agents，polymer fibers，poly-silicon water proof agents on theinsulation mortar has been investigated systematically. The use of re-dispersed emulsionpowders can increase the construction ability and adhesion of the insulation mortar andimprove the toughness of the insulation system. The adding amount of the emulsionpowders has to be controlled within5.0~6.0kg m3.Methyl cellulose ether is theeffective water retention agent. However，it will decrease the strength of the insulationsystem as the ratio between water and cement increases.The adding amount of themethyl cellulose ether has to be controlled within1.5~1.7kg m3.The polypropylenefibers can prevent the insulation mortar from shrinking and increase the toughness andthe anti-cracking ability of hardening insulation mortar. The length of the polypropylene fibers has to be controlled within8~12mm. And the adding amount of thepolypropylene fibers has to be controlled within0.7~1.0kg m3. The organic siliconwater-proof agents can significantly decrease the water adsorbing ability and improvethe water-proof ability. The adding amount of the organic silicon water-proof agents hasto be controlled to be0.6kg m3. We have prepared the polystyrene powder mortar witha superficial density of230Kg/m3，the thermal conductivity of0.056W/cm，compressstrength of0.8，shear bond strength of0.117，absorbing ratio of2.5%，dry shrinkage of0.872‰by surface treatment on polystyrene powder，adding of polymer binders，polypropylene fibers， and so on. The homemade polystyrene powder mortar isadvantages in easy construction process，strength，water-proof，anti-cracking over thetraditional insulation mortar.The anti-cracking mortar is one of the most important components in the insulationsystem. We have investigated the configuration regulation and the physical mechanicalproperties of anti-cracking mortar with special fine sand. We found a regular effect ofthe content of special fine sand and modulus of fineness on the strength and shrinkageratio of mortar. We have prepared the anti-cracking special fine sand mortar with tensilebond strength of0.96MPa，cracking index of1.6，shrinkage of0.565‰in56days.After28days of hardening，the anti-cracking special fine sand mortar possesses astriking energy of8.7J，cracking energy of300.3J m2，and maximum deformation of3.02mm.We have investigated the stress strain behavior of the polystyrene powderinsulation system in the extreme high or low temperature in Chongqing by finiteelement numerical simulation. It was found that the insulation layer has the maximumtemperature gradient and strain，while the anti-cracking layer has the maximumtemperature stress. At the summer with extreme high temperature，the maximum stressof anti-cracking. Therefore，the location with maximum probability of cracking has tobe pre-strength. The stress concentration occurs at the inside corner，outside corner andparapet wall. The widths of stress concentration at the inside corner and outside cornerare0.05and0.08. The widths of stress concentration at the parapet wall are0.35and0.25at plane and parapet orientations，respectively. The anti-cracking layer withconcentrated stress can be strengthened by fiberglass mesh cloth to conquer theinfluence. The four corners at the window hole will meet the concentrated stressphenomenon. The range is about0.32m0.84m with an angle of45from the hole.However，the area of the region of the stress is independent of the size of the hole. In addition there is the stress release occurring at the surround of the hole except thecorners. The polystyrene ribbon at the expansion joint has low elastic modulus. It willrecover under a large stress and strain，which can absorb the stress and strain created bythe temperature variation. The width of the expansion joint has to be larger than8mm.And the interspace between two joints has to be smaller than6m.We have produced the polystyrene powder insulation mortar and anti-crackingspecial fine sand mortar with mass production. We have used them in the buildings ofthe Longhu real estate. To improve the anti-cracking ability，we have put the horizonexpansion joint with a size of10×30mm in every distance of3m.We also use thefiberglass mesh with anti-alkaline treatment at the inside corners，outside corners andparapet corners with occurrence of the concentrated stress. At January2012，we begin toconstruct and it only took two months to finish. At May2012，it was passed through theexamination of building energy saving by the quantity supervision station.The exportershighly appraised the quantity of the construction.更多还原