掺入少量水泥后粉煤灰的工程力学性质

Engineering Properties of Flyash Mixed With a Small Amount of Cement

为扩大粉煤灰的综合利用,笔者在自振柱仪和无侧限剪切仪上对掺入少量水泥的粉煤灰工程力学性质进行了初步试验研究。自振柱试验表明,掺入少量水泥会使粉煤灰低振幅动剪模量明显增加,对徐州电厂粉煤灰,当水泥含量为2～3％时,其动剪模量可与同等相对密度的角砾砂相当;饱和度及试样含水量的变化方式对混合物的动剪模量有所影响;对所用试验材料,七天以后龄期对混合物动剪模量影响不大。无侧限抗压试验的结果与上述基本一致,但对比结果表明无侧限抗压强度随水泥含量而增长的速率较动剪模量的稍快。 可见,掺入少量水泥能明显改善粉煤灰的工程力学性质,从而可能使其成为较好的地基材料。本文为粉煤灰的综合利用初步提供了依据。

To meet the needs of practical engineering, the authors performed the tests of flyash mixed with a small amount of cement by means of free-vibration column device and unconfined compression apparatus. The results of free-vibration tests show that the low-amplitude dynamic shear modulus of flyash will increase remarkably if it is mixed with a small amount of Portland cement. As it is mixed with 2-3% of Portland by weight, the corresponding dynamic shear modulus will be equal to that of angular sand with same relative density.Dynamic modulus is also influenced by saturation of the mixture and its variation pattern, which have little effect on dynamic modulus of the mixure with aging 7 days. Similar results have been obeained from unconfined compression tests on the same materials. It can be seen from the test results and analysis of mechanism that it is possible to improve the engineering properties of flyash, which originally is of low strength and sensible to earthquake, drametically by adding a small amount of po-rtland cement, switching flyash from a useless waste to a dyke material.