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1、學(xué)兔兔www.xuetutu.com2015年第4期(總第306期)混凝土理論研究Number4in2015(TotalNo.306)ConcreteTHEORETICALRESEARCHdoi:10.3969/j.issn.1002—3550.2015.04.001凍融損傷對混凝土斷裂性能的影響研究楊靜,張鵬,趙鐵軍,劉洪珠,張益杰(青島理工大學(xué)土木工程學(xué)院,山東青島266033)摘要:制備水灰比為0.4和O.5的普通混凝土和摻引氣劑混凝土,通過凍融循環(huán)試驗(yàn)、楔形劈裂試驗(yàn),及CONSOFT軟件逆向分析和擬合,研究了凍融循環(huán)損傷對混凝土斷裂能及其應(yīng)變軟化的影響。結(jié)果表明,100次凍融循環(huán)后水灰
2、比為0.4和O.5的普通混凝土相對動(dòng)彈性模量分別下降3O%和55%,而摻加引氣劑混凝土幾乎無動(dòng)彈性模量損失;凍融循環(huán)后,混凝土斷裂能顯著下降,水灰比為0.5的普通混凝土100次凍融循環(huán)后斷裂能損失71%,水灰比0.4時(shí)下降超過5O%,極大削弱了混凝土的軟化韌性;摻加引氣劑混凝土具有良好的抗凍能力,雖然斷裂能也隨凍融次數(shù)的增大而降低,但基體內(nèi)部大量氣泡的存在使混凝土彈性變形能力增大,從應(yīng)變軟化性能來看,其抗拉強(qiáng)度較普通混凝土高得多,呈現(xiàn)較好的韌性。關(guān)鍵詞:混凝土;凍融循環(huán);楔形劈裂;斷裂能;應(yīng)變軟化中圖分類號:TU528.01文獻(xiàn)標(biāo)志碼:A文章編號:1002—3550(2015)04—0001—
3、04InfluenceoffrostdamageonfracturepropertyofconcreteYANG.1ing,ZHANGPeng,ZHA0Tiejun,u【,Hongzhu,ZHANGYijie(DepartmentofCivilEngineering,QingdaoTechnologicalUniversity,Qingdao266033,China)Abstract:Bothnormalconcreteandconcretewithadditionofairentrainingagentwithwatercementratioof0.4and0.5havebeenprepar
4、ed.Throughfreeze—thawcycletestandwedge—splittingtest,theinfluenceoffrostdamageonfracturepropertiesofconcretehasbeenstudied.ThefractureenergyandthestrainsofteningcurvesunderdifferentconditionshavebeenanalyzedbytheprogramCON—SOFTinparticular.Theresultsindicatethatafter100freeze—thawcycles,therelatived
5、ynamicelasticmodulusofnormalconcretewithwatercementratioofO.4and0.5wasreducedby30%and55%,respectively;whileasforconcretewithadditionofairentraininga—gent,therelativedynamicelasticmodulusshowednodecrease.Afteracertainnumberofcyclesoffreezingandthawing,thefractureen—ergyofconcretedecreasedsignificantl
6、y.Thefractureenergyofnormalconcretewithwatercementratioof0.5loss71%after100cy—cles:concretewithwatercementratioof0.4losshigherthan50%.Withadditionofairentrainingagent,concretehadgoodfrostresist-ance.Thefractureenergyalsodecreasedwiththeincreasingoffreeze—thawcycles,however,thebigamountofsmallairbubb
7、lesintro—ducedbyentrainingagentleadtoincreasingofelasticdeformationcapacityofconcrete.Therefore,concretewithairentrainingagenthadmuchhighertoughnessthannormalconcreteafterfreeze—thawcycles.Keywords:co