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本文将探讨用化学和矿物质外加剂混合配制新型高性能湿喷砼(HPS)。使用高效减水剂制备了水灰比在0.42～0.44范围内、坍落度为210～220mm的低坍落度损失砼,并进行湿喷。硅粉(20kg/m~3)被用来减少骨料回弹和增强对基面的粘结力。虽然不如硅酸盐水泥那样早强,火山灰或矿渣水泥(450kg/m~3)也可用来制备耐久砼。在一隧道施工现场,在喷嘴处加入传统的硅酸钠速凝荆和新型的无碱化学外加剂以考察它们在喷砼中作用。硅酸盐碱性速凝剂(12%水泥重)在20～60min内较无碱化学外加剂(7%)有稍高的超早期强度;但用无碱速凝剂制备的喷砼的强度在4h以后则高得多。使用无碱速凝卉4时,现场钻样的抗压强度在4h为2～6MPa、12h为12～15MPa、1d为20～25MPa、7d为45～50MPa、28d为50～60MPa。这些HPS的1～28d抗压强度较免用速凝剂的基准砼低5%～10%。另一方面,使用硅酸钠速凝剂的对等28d强度则要低50%～60%。
This article will explore the use of chemical and mineral admixtures to formulate new high performance wet shotcrete (HPS). The low slump loss concrete with the water-cement ratio in the range of 0.42 ~ 0.44 and the slump of 210 ~ 220mm was prepared by using superplasticizer. Silicon powder (20kg / m ~ 3) is used to reduce the rebound of the aggregate and enhance the adhesion to the substrate. Although not as strong as Portland cement, pozzolan or slag cement (450 kg / m 3) can also be used to make durable concrete. In a tunnel construction site, at the nozzle to join the traditional sodium silicate rapid coagulation Jing and a new non-alkaline chemical additives to investigate their role in the spray concrete. Silicate alkaline quick-setting agent (12% cement weight) in 20 ~ 60min alkali-free chemical additives (7%) slightly higher than the early strength; but with no quick-setting agent prepared spray concrete strength After 4h is much higher. The compressive strength of on-site drilling samples was 2 ~ 6MPa at 4h, 12 ~ 15MPa at 12h, 20 ~ 25MPa at 1d, 45 ~ 50MPa at 7d and 50 ~ 60MPa at 28d. The compressive strength of 1 ~ 28d of these HPS is 5% ~ 10% lower than that of the reference concrete with quick-setting admixture. On the other hand, the equivalent 28d intensity using sodium silicate quick setting agent is 50% -60% lower.