水灰比对大掺量塑料砂浆力学及收缩性能影响研究
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摘要
减小水泥基材料水灰比,提高胶凝材料含量是提高大掺量塑料砂浆力学性能的重要途径,然而,提高胶凝材料含量对大掺量塑料砂浆收缩性能的影响也不容忽视。使用PP塑料等体积替代20%砂子,研究不同水灰比对大掺量塑料砂浆物理性质、力学和收缩性能的影响。结果表明,减小水灰比可有效地补偿大掺量塑料砂浆力学强度,水灰比越小,则抗折强度和抗压强度均越高,近似呈线性关系。此外,水灰比越小,塑料砂浆微结构越密实,孔隙率较低,吸水率越小,密度越大。然而,水灰比越小,自收缩越大,干缩通常也越大。结合试验结果,优选水灰比为0. 3或0. 4。
A low water to cement ratio or high amount of cement in concrete usually contributes to a significant enhancement of the mechanical properties. However,the effect of increasing the content of cementitious materials on the shrinkage properties of large-volume plastic mortars cannot be ignored. The influence of w/c on the physical,mechanical and shrinkage properties of high volume plastic particles mortar( HVPPM) was investigated. Results reveal that a reduced w/c can effectively improve the mechanical strength of HVPPM in an almost linear tendency,including both the compressive strength and the rupture strength. Moreover,a low w/c is also found to be beneficial for gaining a denser microstructure with large density and low water absorption. However,a low w/c increases the autogenous shrinkage as well as the drying shrinkage prominently. Therefore,optimal w/c is determined as 0. 3 or 0. 4.
A low water to cement ratio or high amount of cement in concrete usually contributes to a significant enhancement of the mechanical properties. However,the effect of increasing the content of cementitious materials on the shrinkage properties of large-volume plastic mortars cannot be ignored. The influence of w/c on the physical,mechanical and shrinkage properties of high volume plastic particles mortar( HVPPM) was investigated. Results reveal that a reduced w/c can effectively improve the mechanical strength of HVPPM in an almost linear tendency,including both the compressive strength and the rupture strength. Moreover,a low w/c is also found to be beneficial for gaining a denser microstructure with large density and low water absorption. However,a low w/c increases the autogenous shrinkage as well as the drying shrinkage prominently. Therefore,optimal w/c is determined as 0. 3 or 0. 4.
引文
[1]中国塑料加工工业协会.中国塑料加工工业(2016)[J].中国塑料,2017,31(5):1-5.
[2]赵培生.勿让塑料大国变成塑料垃圾大国[EB/OL].http://info.plas.hc360.com/2016/02/290853549794.shtml,2016-02-29/2018-7-25.
[3]梁炯丰,陈浩,肖烨,等.再生PP塑料混凝土受压性能研究[J].混凝土,2017(5):79-81.
[4]颜勇,李丽娟.再生塑料混凝土静态及动态力学性能硏究[D].广州:广东工业大学,2012.
[5]胡明华,梁炯丰,吴华英.方钢管约束再生塑料混凝土短柱轴压力学性能研究[J].混凝土,2017(11):28-29.
[6]Reis J M L,Carneiro E P.Evaluation of PET waste aggregates in polymer mortars[J].Construction and Building Materials,2012(27):107-111.
[7]ASTM C20.Standard test method for apparent porosity,water absorption,apparent specific gravity,and bulk density of burned refractory brick and shapes by boiling water[S].ASTM International,2015,West Conshohocken,PA.
[8]ASTM C348.Standard test method for flexural strength of hydraulic-cement mortars[S].ASTM International,2002,West Conshohocken,PA.
[9]ASTM C1698.Standard test method for autogenous strain of cement paste and mortar[S].ASTM International,2014,West Conshohocken,PA.
[10]ASTM C596.Standard test method for drying shrinkage of mortar containing hydraulic cement[S].ASTM International,2009,West Conshohocken,PA.
[2]赵培生.勿让塑料大国变成塑料垃圾大国[EB/OL].http://info.plas.hc360.com/2016/02/290853549794.shtml,2016-02-29/2018-7-25.
[3]梁炯丰,陈浩,肖烨,等.再生PP塑料混凝土受压性能研究[J].混凝土,2017(5):79-81.
[4]颜勇,李丽娟.再生塑料混凝土静态及动态力学性能硏究[D].广州:广东工业大学,2012.
[5]胡明华,梁炯丰,吴华英.方钢管约束再生塑料混凝土短柱轴压力学性能研究[J].混凝土,2017(11):28-29.
[6]Reis J M L,Carneiro E P.Evaluation of PET waste aggregates in polymer mortars[J].Construction and Building Materials,2012(27):107-111.
[7]ASTM C20.Standard test method for apparent porosity,water absorption,apparent specific gravity,and bulk density of burned refractory brick and shapes by boiling water[S].ASTM International,2015,West Conshohocken,PA.
[8]ASTM C348.Standard test method for flexural strength of hydraulic-cement mortars[S].ASTM International,2002,West Conshohocken,PA.
[9]ASTM C1698.Standard test method for autogenous strain of cement paste and mortar[S].ASTM International,2014,West Conshohocken,PA.
[10]ASTM C596.Standard test method for drying shrinkage of mortar containing hydraulic cement[S].ASTM International,2009,West Conshohocken,PA.