摘要
为有效增强路面混凝土耐久性能,基于盐冻试验、盐冻前后的断裂性能试验及弯拉荷载疲劳试验,探索了高吸水性聚合物(SAP)自养护路面混凝土抗盐冻性能及疲劳特性随SAP掺量、粒径的变化规律,并结合自养护水泥浆体孔隙参数、微观形貌及骨料-水泥石界面过渡区(ITZ)特征,揭示了性能影响机理。结果表明:小粒径SAP形成的残留孔洞能有效释放拉应力,降低结冰点,细化孔结构,从而增强路面混凝土抗盐冻性能;当SAP粒径为100目(150μm),掺量为0.145%(质量分数)时,路面混凝土在冻融30次时的断裂韧度损失率、断裂能损失率分别比基准组降低了25.25%、10.51%;小粒径SAP对疲劳寿命的提升程度随应力水平的提高而增大,当应力水平为0.80时,自养护组的疲劳寿命相比基准组提升了2.65倍;SAP能够有效提升水泥混凝土结构内部密实度,吸持ITZ区域部分水分,增强水泥石和骨料之间的粘结性,从而改善混凝土抗盐冻性能和疲劳特性。
In order to improve the durability of pavement concrete effectively,the salt freeze-thaw test,fracture performance test before and after salt freeze-thaw cycles,and fatigue test for flexural load were conducted to explore the variation rule of salt frost resistance and fatigue characteristics of super absorbent polymer(SAP)self-curing pavement concrete with different SAP dosages and particle sizes.Combined with the pore parameters,microstructure,and the characteristics of the aggregate-cement interfacial transition zone(ITZ)of self-curing cement paste,the influence mechanism of performance was revealed.The results show that the residual pores formed by SAP with smaller particle size can effectively release the tensile stress,reduce the freezing point and refine the pore structure,which can enhance the salt frost resistance of pavement concrete.After 30 times freeze-thaw cycles,the fracture toughness loss rate and fracture energy loss rate of pavement concrete with SAP particle size of 100 mesh(150μm)and content of 0.145%(mass fraction)decrease by 25.25% and 10.51% respectively,compared with the reference group.The enhancement degree of SAP to fatigue life increases with the increase of stress level.When the fatigue load stress level is 0.80,the fatigue life of pavement concrete is 2.65 times higher than the reference group.SAP can effectively improve the internal compactness of cement concrete structure,hold part of ITZ moisture,enhance the bonding between cement paste and aggregate,thus the salt frost resistance and fatigue characteristics of concrete are improved.
作者
覃潇
许婕婷
申爱琴
吕政桦
谢政专
QIN Xiao;XU Jieting;SHEN Aiqin;LYU Zhenghua;XIE Zhengzhuan(Foshan Land Sea Smart Civil Engineering Material Technology R&D Center,School of Transportation,Civil Engineering and Architecture,Foshan University,Foshan 528225,China;School of Highway,Chang’an University,Xi’an 710064,China;Guangxi Key Lab of Road Structure and Materials,Guangxi Transportation Science and Technology Group Co.,Ltd.,Nanning 530007,China)
出处
《硅酸盐通报》
CAS
北大核心
2021年第8期2784-2793,共10页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金青年科学基金(51908130)
广东省自然科学基金面上项目(2021A1515011716)
广西科技计划项目广西重点研发计划(桂科AB17292032)
佛山科学技术学院研究生自由探索基金(2020ZYTS18)。
关键词
自养护路面混凝土
高吸水性聚合物
抗冻盐性能
疲劳特性
孔结构
界面过渡区
self-curing pavement concrete
super absorbent polymer
salt frost resistance
fatigue characteristic
pore structure
interfacial transition zone
