粉煤灰活性评定新方法

New method of evaluating lime-fly-ash activity

活性是影响粉煤灰路用品质的一项重要指标,目前还没有一种简便宜行的方法评定路用粉煤灰的活性。选取3省14种粉煤灰,采用石灰吸收法对粉煤灰活性进行研究。通过对比研究粉煤灰的氢氧化钙吸收量、需水量比、炭质量分数等指标与二灰混合料早、中期强度之间的关系,提出粉煤灰活性指数指标。该指标综合考虑了粉煤灰的物理、物理化学性质以及火山灰活性度。通过对比活性指数与二灰混合料早、中期强度之间的关系,表明粉煤灰7 d和28 d的强度都与粉煤灰活性值密切相关,活性指数可以用来快速评价和预测二灰混合料的初期强度。

Activity is an important index which affects the performances of lime-fly-ash in highway engineering. Now there is not a reasonable method to evaluate the activity. Fourteen kinds of lime-fly-ash from three provinces in China are selected to study the activity of lime-fly-ash by means of lime-absorbed method. The relations among Ca （OH）2 absorbed content, water requirement ratio, C mass content and their early-middle stage strength of lime-fly-ash mixtures are studied to put forward a new activity index to evaluate road performance of lime-fly-ash. This index takes some features of lime-fly-ash, for instance, physical properties, physic-chemical properties and pozzolanic activity, into account. The relation between the index and early-middle stage strength of lime-fly-ash mixtures is analyzed. The results show that the 7 d strength and 28 d strength of lime-fly-ash have direct relation with the new activity index, this index can be used to evaluate and forecast the initial strength of the lime-fly-ash mixtures. 2 tabs, 3 figs, 8 refs.