废弃物的粉末在水泥基材料中的水化机理及性能影响研究

发布时间：2018-05-02 17:13

本文选题：石灰石粉 + 玻璃粉　；参考：《武汉大学》2014年博士论文

【摘要】：当前,大量的工业废弃物(如粉煤灰、石灰石粉、废弃玻璃等)造成了严重的环境污染和资源浪费。我国是混凝土使用大国,在混凝土中尽可能多的使用廉价的掺合料(特别是工业废料),以替代部分水泥,在保证混凝土的性能的前提下,将其再利用以降低能耗和生产成本,节约资源,减少环境污染,将成为混凝土工业可持续发展的必然趋势。本文针对粉煤灰、石灰石粉、玻璃粉三种废弃物的粉末在水泥基材料中的水化机理及性能影响开展了深入研究,主要工作及结论如下：以掺量、水胶比、养护条件、龄期、细度为条件变量,按照排列组合的方式成型砂浆试件,探讨各种废弃物的粉末对砂浆宏观性能影响。结果表明,低掺量粉煤灰或石灰石粉砂浆后期强度增长较快,复掺粉煤灰与石灰石粉可以有效降低强度损失。掺玻璃粉的砂浆试件强度随龄期增加而增长,最佳掺量为10%。提高玻璃粉细度、降低水胶比、高温养护都会增加玻璃粉的火山灰活性,提高强度。配制不同配合比和不同掺量粉煤灰、石灰石粉的净浆与砂浆试件,将其浸泡在盐酸与硫酸镁复合侵蚀溶液中,其中硫酸镁质量分数为2%,运用pH测试仪测试溶液的pH值变化并采用强度试验、XRD测试方法,观测不同侵蚀时间水泥石强度和侵蚀产物的变化。研究表明,石灰石粉掺量较高及单掺硅粉对于砂浆试件在侵蚀后期的抗复合侵蚀具有不利影响,复掺粉煤灰与硅粉可以改善砂浆试件的抗复合侵蚀性能。在侵蚀早期,石灰石粉含量较多的试件,酸性侵蚀占主要地位,加剧了试件内部胶凝材料的分解。采用砂浆棒快速法,将玻璃粉代替标准砂用作骨料,研究各种骨料替代率条件下,砂浆棒ASR膨胀率大小。掺量为50%时,14d ASR膨胀率最大。将玻璃粉骨料与标准砂以1：1比例成型试件,探讨各种玻璃粉细度、掺量、养护温度、龄期条件下对砂浆棒ASR反应的抑制效果,结合XRD、SEM测试结果,研究了玻璃粉对ASR反应的抑制机理。采用德国TONI Technik公司的ToniCal差热式量热仪,在72h内不间断地测量胶凝材料在水化过程中的放热速率以及放热量,根据化学动力学方法,建立掺粉煤灰、石灰石粉、玻璃粉的水泥基材料水化动力学模型,得出掺粉煤灰的水化反应机制更接近于普通硅酸盐水泥；掺入石灰石粉促进了水泥的早期水化,当石灰石粉掺量增大到50%时,复合胶凝材料的水化反应剧烈且水化过程持续时间较短。玻璃粉的掺入加速了水泥早期水化速率,表现出良好的火山灰活性。采用压汞测试法与吸水动力学方法分析了不同粉煤灰、石灰石粉、玻璃粉掺量下水泥基材料孔径变化,得出标准养护条件下早期掺粉煤灰的水泥基材料孔径分布优于石灰石粉,且随着掺量的增大、水胶比的降低,孔径越均匀,后期由于石灰石粉参与水化,掺石灰石粉的水泥基材料强度增长率更高。由于玻璃粉的填充作用与火山灰活性的发挥,在一定范围内,随着掺量的增加,有害孔隙显著减少,结构更致密。采用正交实验,探讨水胶比、粉煤灰掺量、石灰石粉掺量、是否掺入硅粉对高性能水泥基材料抗压强度的影响,结合XRD、SEM等测试方法,得出粉煤灰对超高性能水泥基材料抗压强度的影响较小。高温蒸养激发了掺有石灰石粉的高性能水泥基材料在短时间内参与水化,并生成较稳定的3CaO·Al203·CaC03·11H2O和3CaO·Al203·3CaCO3(?)32H2O。石灰石粉的早期加速水化作用与纯水泥材料相差并不大。选取玻璃粉磨0.5h、1h、2h三种细度,水胶比0.16、0.20两种,0%、10%、20%、30%四种掺量,研究净浆和砂浆在各种条件下抗压强度的变化。结果表明,在水胶比为0.16时,抗压强度随着玻璃粉掺量的增加而先增后减；在水胶比为0.20时,抗压强度随着掺量的增加而增大,相比较而言,20%掺量为最佳。玻璃粉磨1h及以上时,在高性能水泥基材料中火山灰效应良好,且适当的填充了水泥水化产物的空隙,提高了抗压强度。
[Abstract]:At present , a large amount of industrial waste ( such as fly ash , limestone powder , waste glass , etc . ) has caused serious environmental pollution and waste of resources . Our country is a big country in concrete . As much as possible in the concrete , cheap admixtures ( especially industrial waste ) are used as much as possible in order to replace partial cement . In order to reduce energy consumption and production cost , save resources and reduce environmental pollution , it will become the inevitable trend of sustainable development of concrete industry .

In this paper , the hydration mechanism and the effect of the powder of three wastes , such as fly ash , limestone powder and glass powder , are studied in detail . The main work and conclusion are as follows :

The results show that the strength of mortar specimens with low content of fly ash or limestone powder increases with the increase of age , and the optimum mixing amount is 10 % . The ash activity of glass powder can be increased and the strength can be improved by increasing the fineness of glass powder , reducing water - cement ratio and high - temperature curing .

The results show that the content of limestone powder is 2 % , the pH value of the test solution is changed and the strength test and XRD test method are used to measure the change of the strength and corrosion product of cement stone in different erosion time .

Using the mortar bar method , the glass powder was used as aggregate to replace the standard sand as aggregate . The ASR expansion ratio of mortar bar was the biggest under the condition of substitution rate of aggregate . The inhibition effect of glass powder aggregate and standard sand on ASR reaction of mortar bar was studied . The inhibition mechanism of glass powder on ASR reaction was studied by combining XRD and SEM .

The hydration kinetics model of cement - based materials with fly ash , limestone powder and glass powder was established by using ToniCal differential thermal calorimeter of TONI Technik GmbH in Germany . Based on the chemical kinetics method , the hydration kinetic model of cement - based materials with fly ash , limestone powder and glass powder was established , and the hydration reaction mechanism of fly ash was found to be closer to common Portland cement .
The addition of limestone powder promoted the early hydration of cement . When the content of limestone powder increased to 50 % , the hydration reaction of composite cementitious material was violent and the duration of hydration process was short . The incorporation of glass powder accelerated the early hydration rate of cement and showed good volcanic ash activity .

The pore size distribution of cement - based materials with different fly ash , limestone powder and glass powder was analyzed by mercury - pressing test and hydrokinetics method . It was concluded that the pore size distribution of cement - based materials with early - stage fly ash was better than that of limestone powder under the condition of standard curing .

The influence of cement ratio , fly ash content and limestone powder content on the compressive strength of high - performance cement - based material was investigated by orthogonal experiment . The influence of fly ash on the compressive strength of high - performance cement - based material was studied by means of XRD , SEM and so on .

The results show that the compressive strength decreases with the increase of the content of glass powder when the ratio of cement ratio is 0.16 .
When the water - to - cement ratio is 0.20 , the compressive strength increases with the increase of the mixing amount , and the amount of 20 % is the best . When the glass powder is ground for 1h and above , the volcanic ash effect is good in the high - performance cement - based material , and the voids of the cement hydration product are properly filled , and the compressive strength is improved .

【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU528

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