白云石粉用作矿物掺合料对混凝土耐久性的影响

Influence of Dolomite Powder as Mineral Admixture on Durability of Concrete

用磨细白云石、白云石-水淬矿渣共磨物料作为混凝土矿物掺合料,研究了单掺白云石粉、白云石-水淬矿渣复合矿物掺合料对混凝土耐久性的影响。研究结果表明,单掺白云石粉使C30混凝土的电通量值增加15%,同时使碳化深度增加,并使100次冻融循环后的动弹模量损失率最大达到37.6%,弱化了混凝土的抗氯离子侵蚀性和抗碳化和抗冻性能;而单掺白云石粉使混凝土的抗硫酸盐侵蚀系数提高1.7%,抗硫酸盐侵蚀性能改善。白云石-水渣复合矿物掺合料与单掺白云石粉相比,改善了混凝土的抗氯离子渗透性、抗碳化、抗冻融性能:当水淬矿渣与白云石比例为3.5:6.5时,混凝土的耐久性包括抗氟离子侵蚀性、抗碳化、抗冻性能最好。

The ground dolomite and co-grinding powders of dolomite and water-quendched granulated blost furnace slag were used as concrete admixtures, and the influence of admixture on the durability of concrete are studied. The results show that by single-mixed with dolomite powder, the electric flux of C30 concrete increase by 15%, the carbonation depth increase, and the loss rate of dynamic elastic modulus can reach up to 37.6% after 100 freeze-thaw cycles, the properties of chloride ion penetration-resistant, anti-carbonization and anti-freeze of concrete are weakened;however, the sulphate resistance coefficient of concrete increase by 1.7%, the sulfate resistance is improved. Compared with single-mixed dolomite powder, mixing dolomite-slag composite mineral admixture can improve properties of chloride ion penetration-resistant, anti-carbonization and anti-freeze of concrete, especially when the ratio of slag and dolomite is 3.5：6.5, the durability of concrete will be the best.