典型白云质泥晶灰岩集料的碱碳酸盐膨胀

Alkali Carbonate Expansion with Porphyrotopic Micrite Dolomitic Limestones

研究了以具有典型类斑状结构特征白云质泥晶灰岩作为骨料的混凝土柱在150℃下的压蒸膨胀行为及其膨胀开裂特征.结果表明,基质为泥晶方解石、具有类斑状结构的白云质泥晶灰岩潜在高碱碳酸盐反应(ACR)膨胀性.由ACR引起的膨胀裂缝起始于集料内部的白云石分布密集区,沿白云石晶粒边缘连续延伸、贯穿泥晶方解石基质进而由里向外扩展至水泥浆体.

The autoclaved expansive behaviors at 150 ℃ of micrite dolomitic limestone aggregates with a typical porphyrotopic texture have been explored. The result shows that the micrite dolomitic limestone aggregates with a typical mottled texture are one of potentially ACR active aggregates. The expansion crack patterns by ACR originate from the surface of dolomite crystals, along with the surface between dolomite and micrite matrix, penetrate through the whole aggregate and finally extend into cement pastes outward.