碱激发磷石膏复合胶凝材料力学性能研究

Study on Mechanical Properties of Alkali Activated Phosphogypsum Composite Cementitious Materials

以磷石膏粉、矿粉、粉煤灰和水泥为主要胶凝材料,水玻璃为激发剂,制备了磷石膏复合胶凝材料,研究了水泥掺量(0、5%、10%、15%)和碱当量(0、2%、4%)对磷石膏复合胶凝材料力学性能的影响,并对适用于磷石膏复合胶凝材料的外加剂种类和掺量进行了分析。结果表明:单掺水泥时,随着水泥掺量的增加,磷石膏复合胶凝材料的抗压强度逐渐增大,且当水泥掺量为15%时,28 d抗压强度最大,为22.9 MPa;单掺水玻璃时,随着碱当量增加,磷石膏复合胶凝材料的抗压强度总体呈逐渐增大趋势,且当碱当量为4%时,28 d抗压强度最大;水泥和水玻璃复合使用时的最佳组合为10%水泥+4%碱当量;与聚羧酸减水剂相比,掺萘系减水剂磷石膏复合胶凝材料的28 d抗压强度最高可达39.4 MPa。

Using phosphogypsum powder,slag powder,fly ash and cement as main cementitious materials and sodium silicate as excitation agent,the phosphogypsum composite cementitious materials were prepared,and the effect of cement content(0,5%,10%,15%)and alkali equivalent(0,2%,4%)on the mechanical properties of phosphogypsum composite cementitious materials was studied,and the type and dosage of admixtures suitable for phosphogypsum composite cementitious materials were analyzed.The results show that with the increase of cement content,the compressive strength of phosphogypsum composite cementitious materials increases gradually,and when the cement content is 15%,the 28 d compressive strength is the maximum,which is 22.9 MPa.With the increase of alkali equivalent,the compressive strength of phosphogypsum composite cementitious materials generally shows a gradually increasing trend,and when the alkali equivalent is 4%,the 28 d compressive strength is the highest.The best combination of cement and sodium silicate is 10%cement+4%alkali equivalent.Compared with polycarboxylate superplasticizer,the 28 d compressive strength of phosphogypsum composite cementitious material with naphthalene-based superplasticizer can reach 39.4 MPa.