摘 要：为研究机制砂颗粒形状对砂浆流变性能的影响，使用数字图像处理技术（DIP）对砂颗粒形状进行了定量表征，设计试验测量了砂浆流变曲线并计算了砂浆屈服应力与表观黏度。结果表明，机制砂的长宽比（E）、宽高比（F）比天然河砂分别大14%、18%，说明机制砂棒状和片状程度高于天然河砂；砂浆流变曲线反映出砂颗粒形状不规则会导致砂浆流动阻力增大，在高体积分数下更为显著；根据Chateau模型拟合40%体积分数机制砂砂浆屈服应力是天然河砂的1.5倍；砂浆表观黏度分析发现，机制砂砂浆表观黏度大于天然河砂，在低剪切速率下尤其明显。Abstract:Tostudytheeffectsofmanufacturedsandshapeonmortarrheologyproperty,thedigitalimageprocessing(DIP)methodwasusedtocharacterizesandparticleshapequantitatively,testsofmortarrheologycurvewereperformedanditsyieldstresswascalculatedbyrheologytest.ResultsshowthatEofmanufacturedsand(MS3)is14%biggerthanthatofriversand(RS),FofMS2is18%biggerthanthatofRS,consequently,soparticleshapeofMSismoreelongateandflatthanthatofRS.Besides,rheologycurveresultsshowthattheirregularshapesandwillincreaseresistancewhenmortarflowing,andtheeffectbecomesmoresignificantwithsandvolumeincreasing.BasedonChateaumodel,it′spredictedthatfor40%sandvolumemortar,yieldstressofMS3is1.5timesasRSduetoitsirregularsandshapeofMS3.

周新文,刘建忠,刘光严,等.机制砂颗粒形状对砂浆流变性能的影响研究[J].混凝土与水泥制品,2020(5):1-5. ZHOU X W,LIU J Z,LIU G Y,et al.Study of the Effect of Manufactured Sand Particle Shape on Mortar Rheological Property[J].China Concrete and Cement Products,2020(5):1-5.

摘 要：通过塑性强度、静态屈服应力和跳桌流动度的经时变化试验，研究了纳米黏土与减水剂协同作用对3D打印水泥基材料（3DPC）建造性的影响，并以流变性能为参考依据，建立了3DPC建造性的评价指标。结果表明，复掺纳米黏土和增黏型聚羧酸减水剂的3DPC经时塑性强度和经时静态屈服应力均随纳米黏土掺量增加而提高，纳米黏土的适宜掺量为0.8%；当静态屈服应力时变速率为2.0～4.2Pa/s时，可实现3DPC的挤出性与建造性的协同；在可打印、可建造窗口时间内，3DPC的跳桌流动度为170～190mm。掺用纳米黏土和增黏型聚羧酸减水剂对3DPC的流变参数进行调控是提高3DPC建造性的有效途径。Abstract:Buildabilityisanimportantperformanceparameterof3Dprintingcementitiousmaterials(3DPC).Effectofnano-clayandviscositymodifyingpolycarboxylatesuperplasticizer(VPCE)onbuildabilityof3DPCwasinvestigatedbytestingtimedependentgreenstrength,staticyieldstressandflowtable.Indexesforevaluationthebuildabilityof3DPCwereestablishedbasedonthereferenceofrheologicalparameter.ExperimentalresultsshowthatbothgreenstrengthandstaticyieldstressofVPCEdispersed3DPCincreasewithincreaseofnano-claydosage,andthesuitabledosageofnano-clayis0.8%.Synergybetweenextruderabilityandbuildabilitycanberealizedwhenthestaticyieldstressretentionrateequals2.0～4.2Pa/s.Duringprintwindowtime,flowtablevalueof3DPCis170～190mm.Itisaneffectivewaytoimprovethebuildabilityof3DPCbyrheologymodifyingtechniquebasedonnano-clayandVPCE.

章苏阳,蒋亚清,王玉,等.3D打印水泥基材料的建造性研究[J].混凝土与水泥制品,2020(5):6-9. ZHANG S Y,JIANG Y Q,WANG Y,et al.Research on Buildability of 3D Printing Cementitious Materials[J].China Concrete and Cement Products,2020(5):6-9.

摘 要：为探究高抗蚀硅酸盐水泥提高混凝土的抗渗性能机理，试验研究了普通硅酸盐水泥混凝土及特制高抗蚀硅酸盐水泥混凝土的抗压强度、氯离子扩散系数和直流阶跃电阻率。结果表明，高抗蚀硅酸盐水泥不是通过提高混凝土强度而主要是通过降低内部空隙率及减少连通性来实现混凝土抗渗性的提升。Abstract:Inordertoexplorethemechanismofhighcorrosionresistanceportlandcementtoimprovetheimpermeabilityofconcrete,thecompressivestrength,rapidchloridediffusioncoefficientanddirectcurrentstepinputresistivityofconcretewithordinarycementandhighcorrosionresistantcement(HCRC)werestudied.TheresultsshowthatHCRCcanimprovetheimpermeabilityofconcretenotbyimprovingthestrengthofconcrete,butmainlybyreducingtheinternalporosityandconnectivity.

任雪梅,宋家茂,郝挺宇.高抗蚀硅酸盐水泥提高混凝土抗渗性能机理研究[J].混凝土与水泥制品,2020(5):10-12. REN X M,SONG J M,HAO T Y.Investigation on Mechanism of Permeability of Concrete with High Corrosion Resistant Portland Cement[J].China Concrete and Cement Products,2020(5):10-12.

摘 要：为了研究西部盐渍土环境下混凝土中SO42-的扩散性，测试了在不同溶液、不同干湿循环龄期下，混凝土中不同深度的SO42-含量。采用Fick第二定律为基本模型，考虑SO42-与混凝土结合能力以及混凝土为非均匀介质的特性，对SO42-扩散系数进行了分析讨论。此外，基于XRD结果，分析了侵蚀过程中钙矾石的生长情况以解释说明钙矾石的生成对SO42-扩散性的影响。结果表明，Cl-可促进侵蚀前期SO42-的侵蚀速度；西部盐渍土环境下混凝土中SO42-的扩散系数与结合能力呈负相关关系，与侵蚀深度呈正相关关系；SO42-浓度越高，钙矾石生长越快，钙矾石膨胀作用会填充混凝土的既有裂缝，从而抑制SO42-扩散。Abstract:InordertostudythediffusionofsulfateionsinconcreteunderthesalinesoilenvironmentinwesternChina,thecontentofsulfateionsinconcreteatdifferentdepthsindifferentsolutionsandatdifferentwet-drycycleageswasdetermined.Ficksecondlawwasadoptedasthebasicmodel.Consideringtheabilityofsulfateionstobondwithconcreteandthecharacteristicsofconcreteasnon-uniformmedium,thediffusioncoefficientofsulfateionswasanalyzedanddiscussed.Atthesametime,ettringitecrystalstructurewasrefinedaccordingtotheX-raydiffractionresultsofconcretesamplesaftererosion,andthegrowthofettringiteduringerosionwasanalyzed,soastoexplaintheinfluenceofettringitegenerationonthediffusionofsulfateions.Theresultsshowthatchlorideioncanpromotetheerosionrateofsulfateionintheearlystageoferosion.ThereisanegativecorrelationbetweenthediffusioncoefficientandbindingcapacityofsulfateionsinthesalinesoilofwesternChina,andapositivecorrelationbetweenitandthedepthoferosion.Thehighertheconcentrationofsulfateions,thefasterthegrowthofettringite.Theexpansionofettringitewillfilltheexistingcracksofconcretetoinhibitethediffusionofsulfate.

王岩峰,景浩,闫长旺,等.盐渍土环境下混凝土中SO42-扩散性试验研究[J].混凝土与水泥制品,2020(5):13-17,24. WANG Y F,JING H,YAN C W,et al.Study on the Diffusion of Sulfate Ions in Concrete Under the Saline Soil Environment[J].China Concrete and Cement Products,2020(5):13-17,24.

摘 要：为满足大型电子工业厂房大面积楼板梁结构施工的抗裂性能要求，对比研究了HCSA膨胀剂及复合膨胀剂（MgO膨胀剂与HCSA膨胀剂复掺）的性能，并配制了高抗裂性的补偿收缩混凝土。试验结果表明，两种膨胀剂配制的C40补偿收缩混凝土都具有补偿收缩、防止开裂的效果。掺加复合膨胀剂的补偿收缩混凝土早期强度稍低，温升小，但补偿收缩能力较强，有利于改善大体积深梁与薄板同时浇筑的混凝土结构的抗裂性。Abstract:Theperformanceofdifferentkindsofexpansiveagentwasstudiedforthepreparationofshrinkage-compensatingconcretewithexcellentanti-crackingabilitytosatisfytheconstructingrequirementoflarge-scalebeamandslabstructureofelectronicplant.ThecomparingresultsofusingHCSAexpansiveagentaloneandcomplexlyusingHCSAexpansiveagentandMgOexpansiveagenttogethershowthattheshrinkage-compensatingconcretepreparedwithbothtwokindsofexpansiveagentpossessesanti-crackingability.Theconcretepreparedwithcomplexexpansiveagenthasalittlelowearlystrength,lowtemperaturerisingandstrongshrinkage-compensatingability.Itbenefitstheincreaseofanti-crackingabilityfortheconcretestructureinwhichthelargevolumedeepbeamandthinplateiscastsimultaneously.

阎培渝,陈炜一,赵海涛,等.大面积板梁结构用补偿收缩混凝土的配制[J].混凝土与水泥制品,2020(5):18-20,24. YAN P Y,CHEN W Y,ZHAO H T,et al.The Preparation of Shrinkage-Compensating Concrete for the Construction of Largescale Beam and Slab Structure[J].China Concrete and Cement Products,2020(5):18-20,24.

摘 要：选用复合引发剂调节反应活化能，以异戊烯醇聚氧乙烯醚（TPEG）、丙烯酸（AA）、马来酸酐（MAH）为主要原料，通过工艺调整及工业化设备选型制备了本体聚合固体聚羧酸系保坍剂PC-702S2。通过GPC研究了工业化条件下保坍剂的转化率、分子量及分子多分散性（PDI），并基于红外光谱测试结果讨论了PC-702S2保坍剂的结构特征。研究结果表明，PC-702S2的转化率为94.43%，PDI为1.283，达到常规水溶液聚合保坍剂的性能，切片后的粒径范围≤300μm，适于工业化推广，具有良好的发展前景。Abstract:Byoptimizingcompositeinitiator,adjustingprocessandselectingindustrializedequipment,thesolidpolycarboxylateslump-retainingagentPC-702S2wasindustrialpreparedusingbulkpolymerizationwithTPEG,acrylicacidandmaleicanhydrideasmainrawmaterials.Thepolymerconversionrate,molecularweightandmolecularpolydispersity(PDI)wereanalyzedbyGPC,andthemolecularstructureofPC-702S2wasanalyzedbyinfraredspectroscopy.TheresultsshowthattheconversionrateofPC-702S2is94.43%,PDIis1.283,whichcanreachtheperformanceofconventionalaqueoussolutionpolymerizedslumpretainingagent.Theparticlesizeofsolidproductsisn’tmorethan300μm,whichissuitableforindustrializationandpromotion,andhasbigdevelopmentprospects.

陈国新,祝烨然,杜志芹,等.本体聚合固体聚羧酸系保坍剂的工业化制备及性能研究[J].混凝土与水泥制品,2020(5):21-24. CHEN G X,ZHU Y R,DU Z Q,et al.The Industrial Preparation and Properties of Solid Polycarboxylate Slump Retaining Agent Using the Method of Bulk-polymerization[J].China Concrete and Cement Products,2020(5):21-24.