豹斑白云质泥晶灰岩的混凝土碱骨料反应膨胀行为

Alkali aggregate expansion reaction of mottled micrite dolomitic limestones

研究了具有类斑状结构特征的豹斑白云质泥晶灰岩作为骨料的混凝土柱在150℃压蒸碱骨料反应膨胀行为及其膨胀开裂特征。结果表明,豹斑白云质泥晶灰岩的特点是白云石的晶粒尺寸普遍较大,岩相结构仍属类斑状,也有泥晶与假亮晶方解石两种基质形式;无论基质的特征如何,ASR膨胀值小的豹斑白云质泥晶灰岩混凝土柱AAR膨胀性较弱,膨胀由ACR引起,然而,具有较高ASR膨胀值的岩石容易呈现潜在的高AAR膨胀性,膨胀应归结于ACR与ASR共同作用的结果。基质为泥晶方解石的豹斑泥晶灰岩膨胀裂缝起始于白云石晶粒密集区,裂缝顺白云石与基质方解石之间的界面扩展至水泥浆体。

The AAR expansive behaviors and its crack patterns, autoclaved at 150 ℃, of micrite dolomitic limestone aggregates for concrete bar with a similar porphyrotopic texture were explored .The results show that the mottled micrite dolomitic limestones have a larger crystal size of dolomite,a similar porphyrotopic texture, two matrix forms both micrite and pseudomorph.lt is demonstrated that the concrete bar made from Mottled Micrite Dolomitic Limestones with low ASR expansion had a low AAR expansion and it resulted from ACR.However, the rock with high- er ASR expansion will have a potential higher AAR expansion,which may be ascribed to synergic interaction from ACR and ASR.The expansion cracks from Mottled Micrite Dolomitic Limestones came of dolomite glomerate sites, the crack enlarging into cement paste along the surface between dolomite and calcite in the matrix.