【作者】 肖勇丽；

【导师】 王智；

【作者基本信息】 重庆大学 ， 分析化学， 2008， 硕士

【摘要】 粉煤灰是燃煤电厂排放的一种可再利用固体粉状废弃物,其作为混凝土掺合料能改善混凝土的很多性能,但因其活性低而限制了再利用率,目前有关粉煤灰活性激发的研究已有很多,但均存在不足。而粉煤灰玻璃体为非对称结构,其活性成分和基本体系成分都是极性物质,均具有吸收辐照能量的特性,因此,本文将微波和γ射线两种常用的辐照技术应用于粉煤灰活性激发,并提出了一种粉煤灰活性硅铝快速测定的制样方法。变动微波功率和时间两个参数,对粉煤灰活性进行激发,确定最佳激发参数,在激发剂条件下用最佳参数微波对粉煤灰活性进行激发,得出激发剂条件下微波对粉煤灰活性的影响规律。⑴微波能够提高粉煤灰活性,最佳激发参数为350W微波功率处理10min。⑵微波激发对粉煤灰活性率提高明显,三种粉煤灰的活性率分别提高了9.02%、5.28%和3.03%。⑶微波对粉煤灰砂浆的早期强度提高明显,7d和28d的强度分别提高了55.34%和15.08%,接近于纯水泥试样的强度。⑷激发剂条件下微波对粉煤灰的活性有一定的激发效果,早期激发效果最好的是掺NaCl激发剂组。调节γ射线辐照剂量和时间两个参数,对粉煤灰活性激发进行初步探索。γ射线对粉煤灰-石灰体系活性的激发效果并不明显,但对粉煤灰-石灰-激发剂体系活性的激发效果非常明显,其中激发效果最好的是掺硫酸钠的体系,13d、23d、37d龄期的强度分别能提高326.99%、253.80%、220.15%。γ射线对粉煤灰体系的早期活性激发效果比后期要好,辐照剂量可控制在100KGRe以内。微波加热具有转换效率高、针对性强等优点,将其用于粉煤灰活性硅铝快速测定制样,解决了活性率法采用传统加热方法制样加热时间长、转换效率低、能量损耗大等不足。微波制样方法的最佳参数为210W微波功率处理15min。两种制样方法所测得的粉煤灰活性硅铝的结果相当,误差在试验允许范围内,微波制样快速测定方法可用于粉煤灰活性硅铝的快速测定。更多还原

【Abstract】 Fly ash is a kind of solid powdery waste, which can be used to improve the properties of concrete as addition. However, the secondary utilization of fly ash is restricted by its low activity. The structure of glass phase is asymmetrical, and the active component and basic system of the ash are polar substance. All of the above can absorb irradiance energy. Therefore, we use microwave andγ-ray to activation the activity of fly ash. What is more, a new sample preparation method was introduced to rapidly determine the content of active SiO₂ and Al₂O₃ in fly ash.Research determined the optimal exited parameter with variation of microwave power and time to stimulate fly ash. And the influence law microwave to fly ash was concluded through adding activator and stimulating fly ash with the optimal parameter. The results are described as follows: （1）The activity of fly ash can be improved by microwave, with optimal parameter microwave power and time respectively 350W and 10min. （2）The activation effect to the activity rate of fly ash is obvious by the use of microwave, and the activity rate of three kinds of fly ash have been respectively increased by 9.02%, 5.28% and 3.03%. （3）The compressive strength of fly ash mortar at early age is improved visibly, with strength of 7d and 28d increased by 55.34% and 15.08%, close to that of pure cement specimen. （4）The activation effect to fly ash stimulated by activator is not very good, but the activator of NaCl has some effect to the compressive strength of fly ash at early age.Preliminary research has been done to probe the fly ash activity through adjusting the parameter of irradiation dose and time. The activation effect is not very evident ofγ-ray to fly ash-lime system while it is obvious to fly ash-lime-activator system, especially the system mixed with Na2SO4, compressive strength of 13d, 23d and 37d increased by 326.99%, 253.80% and 220.15%. The activation effect ofγ-ray is better to fly ash at early age, with the irradiance dose controlled no more then 100KGRe.Heating with microwave has higher conversion efficiency and better direction then traditional heating method, which can be used in sample preparation to assess the content of active SiO₂ and Al₂O₃ rapidly. Results indicated that the optimal parameters of microwave power and time are 210W, 15min. Research also showed that the content of active SiO₂ and Al₂O₃ in fly ash assessed by two methods is almost equivalent, hence the microwave sample preparation can be used to rapidly evaluate content of active SiO₂ and Al₂O₃ existed in fly ash.更多还原