岩石结构特征对白云质灰岩碱活性的影响

Influence of rock texture on alkali reactivity of dolomitic limestones

运用LSCM和SEM等对河北唐山白云质灰岩TSA1和TSA2的岩石结构进行分析,并采用RILEM AAR-2、CECS:48、RILEM AAR-5和NRAA 02检测集料的碱活性。结果表明,TSA1和TSA2都不具有碱硅酸活性,TSA1具有碱碳酸盐反应活性,TSA2可能具有潜在碱碳酸盐反应活性;TSA1中白云石-方解石间隙尺寸小于TSA2,其他结构特征无明显差异。白云石-方解石间隙尺寸是影响白云质灰岩碱碳酸盐反应活性的重要因素之一,尺寸越小,ACR膨胀值越大。

Laser scanning confocal microscope and scanning electron microscope are used to analyses the rock texture of the dolomitic limestones TSA1 and TSA2 from Tangshan. Their alkali reactivity are tested by the RILEM AAR-2,CECS:48, RILEM AAR-5 and NRAA 02. The results show that TSA1 and TSA2 are not alkali-silica reactive, TSA1 is alkali-carbonate reactive and TSA2 is the potentially alkali-carbonate reactive. There are no obvious differences in rock textures except that the size of gap between dolomite and calcite in TSA1 is smaller than that of TSA2. The size of gap between dolomite and calcite is an important factor to the alkali-carbonate reactive of the dolomitic limestones. The smaller is size of gap, the greater is expansion of the alkali-carbonate reaction.