矿物掺合料对煤矸石水泥复合体系需水性的影响

Impact of Mineral Admixtures to Water Demand of Coal Gangue-cement

自燃煤矸石具有火山灰活性,可以作为水泥混合材使用。但由于自燃煤矸石表面形态粗糙、颗粒孔隙率较大,当其掺量较大时会引起体系标准稠度需水量增大等问题。本课题通过掺加不同细度、不同掺量的粉煤灰、矿渣、石灰石粉和硅灰四种矿物掺合料,研究矿物掺合料对自燃煤矸石水泥复合体系需水性的影响。结果表明,分别复掺5wt%的矿渣、石灰石和工业硅灰三种矿物掺合料,可明显降低自燃煤矸石-水泥复合体系标准稠度需水量。其中复掺粉磨40 min石灰石减水率为4.4%;复掺粉磨30 min矿渣减水率为6.2%;复掺工业硅灰减水率达到10.2%。复掺矿物掺合料后,自然煤矸石-水泥复合体系早期强度稍有降低,但后期强度有所增强,其中复掺5%工业硅灰,28 d抗压强度提高2.5 MPa。

Spontaneous combustion gangue has volcanic activity so that can be used as a cement admixture. However, due to the problem such as the rough surface morphology, large particle porosity and particle size distribution, it will cause system standard consistency water demand increases and other issues when the dosage is large. This paper studies the impact of mineral admixtures on water demand of spontaneous combustion gangue-cement composite system by adding different fineness, different contents of fly ash, slag, limestone and silica fume four kinds of mineral admixtures. The result shows that respectively admixed 5wt% slag, limestone, silica fume three kinds of industrial mineral admixtures can significantly reduce the water requirement of normal consistency of spontaneous combustion gangue- cement composites. The water reduction of admixing limestone that grinding 40 min was 4.4%. The water reduction of admixing slag that grinding 30 min was 6.2%. The water reduction of admixing silica fume was 10. 2%. After re-mixed mineral admixtures, the early strength of natural gangue-cement composites slightly lower, but later strength has been enhanced. When complex with 5% industrial silicon doped ash, the 28 d compressive strength improved 2.5 MPa.