【作者】 周健；

【导师】 苗苗；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2017， 硕士

【摘要】 补偿收缩混凝土已广泛应用于结构自防水、超长结构无缝施工、大体积混凝土等领域。本文针对应用中存在的一些问题,如水化热的集中释放导致混凝土内部水化温度高于常温进而影响胶凝材料水化过程,大掺量的矿物掺合料使水化环境更加复杂,研究了水化温度、矿物掺合料掺量、膨胀剂对水泥-矿物掺合料-膨胀剂复合胶凝体系水化特性的影响。试验研究主要内容有:水化温度、矿物掺合料掺量、膨胀剂对复合胶凝体系胶砂试块强度和限制膨胀率的影响及二者匹配关系;三个因素对复合胶凝材料体系水化热的影响;用Krustlovic-Dabic模型模拟复合胶凝体系水化过程,探讨不同因素对其水化动力学影响;测定复合胶凝材料化学结合水量和矿物掺合料的反应程度,分析水化温度、矿物掺合料和膨胀剂等因素的影响机理。研究结果表明:①在不同的养护温度条件下,养护温度越高,膨胀剂的膨胀效能发挥越快,限制膨胀率越早稳定,最终的限制膨胀率越大;不同掺量的粉煤灰对强度和膨胀的影响范围相对矿渣更大;60℃养护时强度和膨胀的规律与20℃、40℃时的不相同,较高的水化温度虽促进了水化,但是也使得强度和膨胀的矛盾扩大化;不同的养护温度条件下,HCSA膨胀剂的膨胀性能和强度优于ZY膨胀剂,对温度的敏感性也相对较低。②掺入膨胀剂会导致复合胶凝体系诱导期结束时间提前,掺入矿物掺合料会使诱导期结束时间推迟;掺HCSA膨胀剂比掺ZY膨胀剂水化放热速率更快,最终放热量更高,掺入矿物掺合料后第二放热峰会降低,最终放热量受矿物掺合料种类、掺量和膨胀剂种类、水化温度等因素的影响;温度激发和碱激发作用会叠加,可以让前期活性有限的矿物掺合料更早更快地发生火山灰反应。③Krstulovic-Dabic模型能较好适用于水泥-矿物掺合料-膨胀剂复合胶凝体系,其水化反应过程均经历结晶成核和晶体生长过程(NG)、相边界反应过程(I)和扩散过程(D)三个阶段。矿物掺合料、膨胀剂、水化温度对各个阶段水化动力学参数均有影响。温度加速水化反应;掺入矿物掺合料使整个水化反应更加和缓;ZY膨胀剂对温度的敏感性比HCSA膨胀剂高。掺膨胀剂和矿物掺合料均会降低复合胶凝体系的表观活化能。④随龄期的增长,复合胶凝体系化学结合水量和矿物掺合料反应程度也增长;矿物掺合料掺量大,其反应程度变小,胶凝体系化学结合水量小;高温养护提高了矿物掺合料反应程度和胶凝体系的化学结合水量,对矿渣反应程度的提高大于对粉煤灰反应程度的提高。更多还原

【Abstract】 Expansive Concrete has been widely used in structures such as self-waterproofing,long structure seamless construction,mass concrete and other fields.In this paper,some problems in the application,such as the concentrated release of hydration heat,lead to the hydration temperature of the concrete,which is higher than the normal temperature,which affects the hydration process of the cementitious material,the large amount of mineral admixture makes the hydration environment more complicated,studied effect of hydration temperature,mineral admixture content and expansive agent on hydration characteristics of cement-mineral admixture-expansive agent composite cementitious System.The main contents of the experimental study are: hydration temperature,mineral admixture content,expansive agent on the composite cementitious system mortar strength and restricted expansive ratio and the coordination between the two;The influence of different factors on the hydration kinetics was studied by Krustlovic-Dabic model.The chemical bound water of composite cementitious systems and reaction degree of material admixtures were determined.The mechanism of hydration temperature,mineral admixture and expansive agent was analyzed.Research results indicate:①Under different curing temperature,the higher the curing temperature,the faster the expansive effect of the expansive agent,the sooner the stability of the limiting expansion rate,the greater the restricted expansive rate;the influence of fly ash on the strength and expansive of the impact of the scope is larger than slag;higher hydration temperature promotes hydration,but also makes the contradiction between strength and expansive The HCSA expansive agent is better than ZY expansive agent under different curing temperature on the sensitivity to temperature.②Expansive agent will lead to the induction period of the composite cementitious system come earlier,mineral admixtures will delay the end of induction period;the HCSA expansive agent is faster than the hydration heat dissipation rate of ZY expansive agent,The final exothermic energy is affected by the factors such as mineral admixture type,dosage and expansion agent type,hydration temperature and other factors;temperature excitation and alkali excitation The role of superposition,you can let the early limited activity of mineral admixtures earlier and faster volcanic ash reaction.③The Krstulovic-Dabic model can be applied to the cement-mineral admixtureexpansive agent composite cementitious system,and its hydration reaction process undergoes crystallization nucleation and crystal growth process(NG),phase boundary reaction process(I)and diffusion process(D).Mineral admixtures,expansive agents,and hydration temperatures have distinct effect on the hydration kinetic parameters at each stage.The temperature sensibility of the ZY expansive agent is higher than that of the HCSA expansive agent.The addition of the mineral admixture to the whole hydration reaction is more moderate.Both the expansion agent and mineral admixture will reduce the apparent activation energy of the composite cementitious system.④With the growth of the age,the chemical bound water of the composite cementitious system and the reaction degree of mineral admixture also increased;the mineral admixture content is large,the reaction degree and the chemical bound water becomes smaller;The high temperature curing improves the reaction degree of the mineral admixture and the chemical bound water,and the improvement of the reaction degree to the slag is greater than that of the flyash.更多还原