磷石膏、菱镁矿粉及其二元复掺对混凝土早期体积收缩等性能的影响

Effect of phosphogypsum,magnesite powder and their dual double mixing on the properties of concrete early-age volume shrinkage,etc

本文探讨了磷石膏(PG)、菱镁矿粉(MP)及其二元(PG/MP)复掺对混凝土早期体积收缩性能和抗压强度的影响.实验结果表明,随着PG掺量增加,抗压强度会显著降低.4%MP掺量下抗压性能最好.复掺情况下在同时掺入2%PG,2%MP所得抗压强度最高.PG,MP均会降低混凝土收缩速率,尤其在单掺MP时混凝土的早期收缩速率降低得最多,通过SEM与XRD分析,随着混凝土内部碱-碳酸盐反应(ACR)的进行,MP能有效抑制混凝土早期的体积收缩.在PG/MP二元复掺体系下PG不仅可以作为一种缓凝剂,而且还可以作为一种膨胀剂,在两种物质互相协同作用下,能使混凝土抗压强度及早期体积稳定性更优.

In the dual-mixed concrete of phosphogypsum/magnesia powder(PG/MP),the effects of the amount of Phosphogypsum(PG)and magnesite powder(MP)on the strength and volume shrinkage of concrete were discussed.The experimental results show that with the increase of PG content,the compressive strength will be significantly reduced.4%MP has the best compressive performance.When mixed with 2%PG and 2%MP,the compressive strength is the highest.PG and MP can reduce the shrinkage rate of concrete,especially when MP is added alone.Through SEM and XRD analysis,with the reaction of alkali carbonate(ACR)in concrete,MP can effectively inhibit the early volume shrinkage of concrete.In the binary mixed system,PG can be used not only as a retarder,but also as an expansion agent.The two substances cooperate with each other to make the compressive strength and early volume stability of concrete more excellent.