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1、學(xué)兔兔www.xuetutu.com第18卷第3期建筑材料學(xué)報Vo1.18。No.32015年6月JOURNALOFBUILDINGMATERIALSJun.,2015文章編號:1007—9629(2015)03—0471-06車橋耦合振動對混凝土早期性能的影響及其損傷機(jī)理蔣正武,任強(qiáng),袁政成(同濟(jì)大學(xué)先進(jìn)土木工程材料教育部重點實驗室,上海201804)摘要:在分析車橋耦合振動參數(shù)變化規(guī)律的基礎(chǔ)上,提出了合理的振動模擬試驗方法與評價指標(biāo),研究了車橋耦合振動參數(shù)對不同水膠比混凝土性能的影響,并結(jié)合微觀結(jié)構(gòu)試驗
2、結(jié)果,探討了混凝土損傷機(jī)理.研究發(fā)現(xiàn):車橋耦合振動會加速混凝土的泌水,降低實際水膠比,一定程度上有利于其抗壓強(qiáng)度測試值的提高,但會提高混凝土內(nèi)部大于200nm的多害孔比例,同時加劇石子下沉和漿體上浮,使得混凝土早期離析程度增大,均勻性降低,密實度降低,從而降低混凝土長期性能.在混凝土凝結(jié)硬化初期(貫入阻力≤0.5MPa)和后期(貫入阻力≥28.0MPa),車橋耦合振動產(chǎn)生的破壞作用較?。辉谀Y(jié)硬化中期(貫入阻力為0.5--~28.0MPa),車橋耦合振動會導(dǎo)致混凝土內(nèi)部產(chǎn)生永久微裂紋等缺陷,對混凝土性能影響
3、較大.關(guān)鍵詞:耦合振動;頻率;損傷;機(jī)理中圖分類號:TU528.01文獻(xiàn)標(biāo)志碼:Adoi:10.3969/j.issn.1007—9629.2015.03.019EffectsofVehicle-BridgeCoupledVibrationonEarly-AgePropertiesofConcreteandItsDamageMechanismJIANGZhengwu,RENQiang,YUANZhengcheng(KeyLaboratoryofAdvancedCivilEngineeringMaterial
4、sofMinistryofEducation,TongjiUniversity,Shanghai201804,China)Abstract:Thevariationlawofvehicle-bridgecoupledvibrationwasanalyzedandareasonablemethodtosimulatecoupledvibrationin1abaswel1astheevaluationindexeswasproposed.Thentheeffectsofvehi—cle—bridgecouple
5、dvibrationparametersonthepropertiesofconcretewithdifferentwater-cementratiowerestudied.Thedamagemechanismofvehicle—bridgecoupledvibrationonconcretewasinvestigatedac—cordingtothemicrostructureresults.Theresultsindicatethatundervehicle-bridgecoupledvibration
6、,thebleedingofconcreteaccelerates,theactualwater—cementratioreduces,andthecompressivestrengthin—creasestoacertainextent.However,theearlysegregationofconcreteisaggravatedbythevibration,whichleadstoworseuniformityandcompactness.Thelong—termperformanceofconcr
7、eteisdeterioratedasseenfromahigherproportionofdeleteriouspores(~200nm)ofconcrete.Attheearlyage(i.e.pene—trationresistanceS0.5MPa)ofsettingandlaterage(i.e.penetrationresistance≥28.0MPa)ofharden—ing,thenegativeinterferenceofvehicle-bridgecoupledvibrationisin
8、significant,however,vehicle—bridgecoupledvibrationcan1eadtoalotofirreversiblemicro—cracksinconcreteatthemiddleage(i.e.penetra-收稿日期:2013—03—05;修訂日期:2013—04—04基金項目:國家重點基礎(chǔ)研究發(fā)展計劃(973計劃)項目(2011CB013805);國家自然科學(xué)基金資助