减水剂对PVA-ECC高温后力学性能的影响试验

Experimental reasearch on influence of super plasticizier on mechanical properties of PVA-ECC

对加入减水剂和未加入减水剂的聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)测定了不同温度作用后的立方体抗压、棱柱体抗折及薄板抗弯强度.发现加减水剂PVA-ECC的各项残余力学性能均比无减水剂PVA-ECC的对应值大;室温状态下的立方体抗压强度增加85%,棱柱体抗折强度增加38%,薄板抗弯强度增加60%.与室温值相比,无减水剂试件在200℃时的立方体抗压强度和棱柱体抗折强度分别增加3.9%、8.7%,薄板3点抗弯强度下降14.1%,加减水剂试件对应的3项力学性能则分别降低31.4%、55.3%、39.7%.而当达到400℃时,无减水剂试件的棱柱体抗折和薄板抗弯强度损失率分别达75.7%和62.5%.600℃时,无减水剂薄板只剩1块,其余2块已经剥落.800℃时,无减水剂立方体试件已经剥落,加减水剂立方体试件的抗压强度损失率也已达80.1%.

The polyvinyl alcohol fiber reinforced cementitious composites （PVA-ECC） with super plastici- zer（SP） added or not has been tested for compressive,flexural and bending properties after high temperatures. It is found that under the same temperature, PVA-ECC added SP performs better than not added ones; when under room temperature, compressive strength, prism and sheet＇s bending strengths for PVA-ECC added SP are respectively higher 85%, 38% and 60% than PVA-ECC not added SP; when the temperature reached up to 200 ℃,the not added one＇s compressive strength and prisim bending strength increase 3.9% and 8.7% ; thin sheet bending strength decreases 14. 1% ; PVA-ECC added SP decrease 31.4%,55.3% and 39.7% respectively. While at 400 ℃,the bending strength loss rate about not added one＇s prisim and thin sheet abruptly decrease to 75.7% and 62.5%. At 600℃ ,only one not added SP thin sheet remaines, the two others has spalled. At 800 ℃ ,all of not added SP cubic specimens have spalled; the added one＇s compressive strength loss rate also reaches up to 80.1%.