用硅粉水泥砂浆修复船闸闸墙

对于用硅粉水泥砂浆修复钢筋混凝土船闸闸墙、从材料机理、施工工艺和实践效果等方面进行实地试验和跟踪观测,并作为优质修复材料予以推荐。

动静加载下微硅粉-橡胶/水泥砂浆的力学性能

为研究微硅粉(Micro silicon powder,MP)-橡胶/水泥砂浆的力学性能,试验设计了16组试件,通过单轴抗压试验与抗冲击试验(分离式霍普金森压杆(SHPB))分析不同微硅粉掺量、橡胶粒径和养护龄期试件的峰值应力、峰值应变、弹性模量、抗冲击强度、破坏形态与应力-应变曲线。单轴抗压试验表明:在相同的养护龄期下,橡胶颗粒的加入使砂浆试件的抗压强度与弹性模量降低,峰值应变增加,加入微硅粉后试件的强度与弹性模量会有所回升。抗冲击试验表明:橡胶会降低砂浆的抗冲击强度,但能改善砂浆的破坏形态,而微硅粉不仅能增强这种改善作用,还能提升橡胶/水泥砂浆的抗冲击强度,另外加入微硅粉后,试件的应力-应变曲线的峰值荷载会由于其弹性变形与弹塑性变形阶段的缩短而向左偏移,但破坏阶段明显延长。

Performance evaluation of nano-silica and silica fume on enhancing acid resistance of cement-based composites for underground structures

This study aims to evaluate the performance of silica fume(SF)and nano-silica(NS)on enhancing the sulfuric acid resistance of mortar mixtures.The NS and SF were added as substitutions for cement at various dosages.The cured samples were immersed in the sulfuric acid solution with a pH of 2 for 75 d.A compressive strength test and absorption and voids tests were conducted before sulfuric acid immersion.It was found that the addition of SF and NS reduced the volume of permeable voids and increased compressive strength.A thermo-gravimetric analysis was carried out to investigate the hydration of mixtures.The mixtures with SF showed a higher level of pozzolanic reaction compared with mixtures with NS.After the 75 d of immersion,the mixtures with 5%SF and 1%NS showed the best resistance against sulfuric acid because they showed the lowest mass change and length change.