制备工艺对工程弃土人工骨料性能的影响

Influence of Preparation Process on the Performance of Artificial Aggregates of Engineering Waste Soil

为处置大量工程弃土,同时缓解工程建材短缺问题,利用工程弃土制备人工骨料,以期揭示成型压力、黏结剂类型与掺量、硬化工艺与养护时间等关键因素对人工骨料性能的影响,试验表明,①增大成型压力有利于提高人工骨料的强度与致密性,但当成型压力达到30 MPa时,部分试件的黏结剂会被挤出,导致抗压强度下降;②水泥与地质聚合物黏结剂对人工骨料各指标的影响规律基本相同,随着黏结剂掺量的提升,骨料的抗压强度显著提高,吸水性逐渐下降;③热养护-冷结硬化工艺会加快黏结剂的水化反应,提高骨料的吸水性,降低骨料的毛体积密度。使用热养护-冷结硬化工艺制备的地质聚合物人工骨料7 d强度能够达到冷结硬化骨料的28 d强度。

In order to dispose of a large amount of engineering waste soil and alleviate the shortage of engineering building materials,engineering waste soil is used to produce artificial aggregates,so as to reveal the effects of key factors such as molding pressure,binder type and dosage,hardening process and curing time on the performance of artificial aggregates.The main conclusions are as follows:(1)Increasing the molding pressure is beneficial for improving the strength and density of artificial aggregates,but when the molding pressure reaches 30 MPa,some of the binders of the specimens will be squeezed out,causing a decrease in compressive strength;(2)The influence of cement and geopolymer binders on various indicators of artificial aggregate is basically the same.With the increase of binder content,the compressive strength of the aggregate significantly increases,while the water absorption gradually decreases.(3)The hot curing cold hardening process will accelerate the hydration reaction of the binder,improve the water absorption of the aggregate,and reduce the gross bulk density of the aggregate.The 7 d strength of geological polymer artificial aggregates prepared using the hot curing cold hardening process can reach the 28 d strength of cold hardening aggregates.