橡胶颗粒掺量对玻化微珠保温砂浆性能的影响研究

选取10%、20%、30%3种掺量,将0.55～2.36 mm改性橡胶颗粒掺入玻化微珠保温砂浆中,制备了20组保温砂浆试块,研究了橡胶颗粒掺量对玻化微珠保温砂浆抗冻性能和保温性能的影响.结果表明:随着橡胶颗粒掺量的增加,保温砂浆的抗压强度逐渐降低;橡胶颗粒能够改善保温砂浆的抗冻性能,橡胶颗粒掺量越高,经历相同次数的冻融循环作用后,保温砂浆的质量损失率和强度损失率越小,随着冻融循环次数的增加,保温砂浆的质量损失率和强度损失率的下降幅度越平缓,抗冻性能越好;由于橡胶颗粒在保温砂浆中引入的封闭孔隙减少了对流传热,保温砂浆的保温性能随着橡胶颗粒掺量的增加而提高.     

废旧轮胎胶粉对水泥砂浆力学性能的影响

研究了废旧轮胎胶粉的细度、掺量对水泥砂浆抗压强度的影响．利用不同的硅烷偶联剂对废轮胎胶粉进行了改性试验，并测定了改性胶粉对水泥砂浆力学性能的影响．研究结果表明：掺胶粉水泥砂浆28d抗压强度有明显下降，但掺量小于10％时，对水泥砂浆的早期强度几乎没有影响；在等掺量条件下，胶粉越细，砂浆强度越高；胶粉经改性后能明显改善掺胶粉水泥砂浆的力学性能．     

表面改性丙纶增强水泥砂浆制品的研究

研究了表面改性丙纶对水泥砂浆制品的增强作用，结果表明，在水泥砂浆制品中混入表面改性丙纶可提高水泥砂浆制品的固化速率，减小水泥砂浆制品的龟裂，提高水泥砂浆制品的抗冲击强度和抗折强度，当纤维加入量为1.6kg/m^3时，抗冲击强度和抗折强度有最大值。     

聚合物改性水泥砂浆基础研究

通过相应的实验，对聚合物改性水泥砂浆作出一定研究，采用氯丁胶乳、聚乙烯醇溶液、乙烯一醋酸乙烯共聚乳液EVA三种不同聚合物作为改性剂，分析最佳配比及工艺参数，根据实验数据探讨力学性能及改性效果，分析微观结构，探讨其改性机理，给出研究聚合物改性水泥砂浆的一般方法。     

聚合物干粉改性水泥砂浆性能及应用研究

研究了掺羟乙基甲基纤维素醚和乙烯-醋酸乙烯酯共聚物乳胶粉的改性水泥砂浆的各项物理性能及其断面形貌。试验结果表明,2种聚合物均具有很好的保水功能,能使砂浆的水分更多、更长时间地保留在水泥浆体中,从而保证了水泥砂浆的充分水化,减少了浆体的分层离析现象,使砂浆具有良好的施工和易性;聚合物的引气功能,使新拌水泥砂浆的体积密度下降,且引入的空气在硬化砂浆中形成孔径小且分布均匀的微孔,因而改性砂浆的抗吸水能力提高;聚合物的种类、掺量对砂浆的各项性能有很大的影响,复掺能充分发挥不同聚合物对砂浆的改性作用,且聚合物间存在一个合适的掺量范围。聚合物改性水泥砂浆适合商品化生产,通过改变聚合物的掺量可满足现代施工对砂浆不同功能的需求。     

橡胶—沥青改性机理的研究

通过电镜照片，颗粒分布，红外光谱研究橡胶－沥青的改性机理，讨论了改性沥青结构与性能之间的关系，并提出了制备性能好的改性沥青的途径。     

在重钙和膨润土作用下聚合物对水泥砂浆的改性作用

研究了在重钙和膨润土作用下，在水泥砂浆中加入不同种类和不同掺量聚合物对水泥砂浆性能的影响，并提出合理的聚合物掺量值。     

高掺量废旧橡胶改性环氧树脂混凝土力学性能与路用性能

为了提高废旧橡胶掺量和探讨废旧橡胶改性环氧树脂混凝土作为路面铺装材料的可行性,采用废旧橡胶等体积替代砂石集料制备了高掺量(0~50%)废旧橡胶改性环氧树脂混凝土(waste rubber modified epoxy concrete,REC),考察了REC的孔隙率、力学性能和路用性能.结果表明,随着橡胶掺量增大,REC孔隙率先增大后趋于稳定;抗压强度和抗折强度均呈近似线性降低,抗压极限应变和抗折极限应变在掺量低于40%时均基本保持稳定而折压比缓慢增大,在掺量高于40%后三者显著增大;抗压应力-应变曲线趋于平缓,柔性因子增大;高温稳定性、低温稳定性和抗滑性能均增强;耐冻融性能均优良,但水稳定性降低明显.建议REC作为路面铺装材料时橡胶掺量20%为宜,此时具有较好的力学性能和路用性能:抗压强度为33.5 MPa,抗折强度为23.6 MPa;车辙试验:永久变形为0.48 mm,动稳定度达70 000次/mm;低温弯曲试验:抗折强度为17.0 MPa,破坏应变为3.1×10-3;水稳定性试验:浸水马歇尔残留稳定度为75.67%;抗滑试验:摆值(British pendulum number,BPN)值为48;冻融试验:300次冻融循环无裂缝或材料破落,无质量损失.考虑REC水稳定性能一般,建议尽量避免用于水损害严重的地区.     

废橡胶粉的改性及其对水泥砂浆性能的影响

选用极性单体马来酸酐(MAH),在非隔氧条件下以过氧化苯甲酰(BPO)为引发剂对废弃橡胶粉表面进行接枝改性.通过傅立叶红外光谱对接枝产物进行测试,结果表明在1 700 cm-1附近出现酸酐的羰基官能团(CO)特征峰.橡胶细集料掺量同为60 kg/m3时,改性橡胶细集料砂浆28 d抗压强度较改性前基本持平,而用NaOH和马来酸酐改性后砂浆的28 d抗折强度较改性前分别提高11.4%和5%,说明采用改性橡胶粉可使水泥砂浆硬化体韧性、延展性提高.     

芳纶纤维橡胶混凝土的塑性开裂与韧性研究

为探究掺加芳纶纤维对橡胶混凝土的韧性、抗裂性的影响,将40目橡胶粉等体积替换7.5％细骨料制成橡胶混凝土,并加入不同掺量的芳纶纤维,采用平板试验及落锤试验,分别研究了纤维橡胶混凝土的抗裂性能及冲击韧性.结果 表明:掺入芳纶纤维对橡胶混凝土的抗压强度提升不明显,但显著提高了冲击韧性和抗塑性开裂;在芳纶纤维掺量为0.7％时,试件的抗冲击韧性比达到最大值4.125,比橡胶混凝土增加了大约3倍;芳纶纤维掺量分别为0．3％、0.5％、0.7％时,混凝土未出现裂缝,有效提高了混凝土抵抗开裂的能力.     

Hybrid modified rubber powder and its application in cement mortar

This research focused on using the waste rubber powder as a kind of regenerate resources to improve the mechanical properties of cement mortar. The two kinds of hybrid modified rubber powder TRP and ATRP were prepared by sol-gel method and then used in cement mortar. The structures and properties of them were studied. It is shown that the nano Si-O-Si network is generated in TRP and ATRP networks and the hydrophilic group is grafted on the surface of ATRP. The mechanical properties of rubber-treated mortar (RTM) were tested and the microstructures of them were also studied. Compared to the mortars with unmodified rubber powders (RP), NaOH treated rubber powder (SRP) and coupling agent treated rubber powder (CRP), the RTM with ATRP has the highest compressive strength and flexural strength. The stress-strain curves shown that the peak of stress of RTM with ATRP is increased and indicated the higher compression deformation and toughness. It is found that the interfacial adhesion between the ATRP and cement mortar is increased distinctly by SEM, which results in enhanced ductility and mechanical properties of RTM with ATRP.     

Effect of rubber particles on cement stabilized gravel system

The primary objective of this paper was to study the mechanical properties and durability of the cement stabilized gravel by different compact method. The influence of rubber particle content on mechanical properties of samples was studied by compaction tests and freezing thawing recycle tests. Pore structure and fractal characteristic of mixture were analyzed quantitatively using mercury intrusion porosimetry （MIP）. X-ray diffraction （XRD） was adopted to identify the composition phases. The morphology analysis in micro scale and elemental analysis of samples were carried out by scanning electron microscope （SEM）. The optimum compressive strengths of rubber cement stabilized gravel （RCSG） with static compaction method and with vibratory compaction method were obtained by controlling compaction degree and vibration time, respectively. From the compaction tests, the vibratory compaction method is preferred compared with the static compaction method as better compressive strength can be improved by about 340%-360%. Besides, test results also reveal that compressive strength of samples with vibratory compaction method or static compaction method will decrease with the rubber particle bulk content increasing. The freezing thawing recycle tests indicate that freezing thawing resistance has been improved （frozen stability coefficient K has been increased from 0.89 to 0.97） by the addition of rubber particles. MIP tests show that the mean pore diameter and porosity of mixture have been increased from 70 to 250 nm and 9% to 24% respectively, with the rubber particles content increasing. Component analysis shows that the calcium silicate hydrate （CSH） is the predominant hydrate product with or without the addition of rubber particles.     

胶粉改性聚苯乙烯材料的制备与性能

以聚苯乙烯(PS)为基体材料,制备废旧胶粉(WRP)改性聚苯乙烯材料;并探讨了胶粉增韧剂SBS和偶联剂用量对胶粉改性聚苯乙烯材料的综合物理性能的影响.     

胶粉改性丁苯橡胶的制备与性能

以丁苯橡胶(SBR)为基体材料,制备废旧橡胶粉(WRP)改性丁苯橡胶材料.研究羟基、马来酸酐、双键、有机硅氧烷等不同改性剂改性的胶粉,以及未改性废旧胶粉对丁苯橡胶综合物理性能的影响.     

灌注式半刚性路面橡胶粉水泥砂浆物理力学性能试验研究

通过对灌注式半刚性路面橡胶粉水泥砂浆进行物理力学性能试验,研究表明:将不同掺量的橡胶粉代替同体积的砂掺入水泥砂浆所制得的橡胶粉水泥砂浆含气量有所提高,而且具有良好的流动性、较小的干缩率,凝结时间也有所增长;在力学性能方面,抗压强度会随着橡胶粉掺量的增加而降低,而抗折强度则会随着橡胶粉掺量的增加,呈现出先增后减的趋势;在耐磨性能方面,橡胶粉水泥砂浆的耐磨性也是随着橡胶粉掺量的增加,出现先提高后降低的变化趋势;这些都为后续所开展的橡胶粉水泥砂浆最佳配比研究以及灌注式半刚性路面面层复合材料路用性能的研究提供了依据.     

Effect of strain rate and water-to-cement ratio on compressive mechanical behavior of cement mortar

Effects of strain rate and water-to-cement ratio on the dynamic compressive mechanical behavior of cement mortar are investigated by split Hopkinson pressure bar(SHPB) tests. 124 specimens are subjected to dynamic uniaxial compressive loadings.Strain rate sensitivity of the materials is measured in terms of failure modes, stress-strain curves, compressive strength, dynamic increase factor(DIF) and critical strain at peak stress. A significant change in the stress-strain response of the materials with each order of magnitude increase in strain rate is clearly seen from test results. The slope of the stress-strain curve after peak value for low water-to-cement ratio is steeper than that of high water-to-cement ratio mortar. The compressive strength increases with increasing strain rate. With increase in strain rate, the dynamic increase factor(DIF) increases. However, this increase in DIF with increase in strain rate does not appear to be a function of the water-to-cement ratio. The critical compressive strain increases with the strain rate.     

改性胶粉对聚苯乙烯结构及力学性能的影响

将微波辐射改性胶粉与聚苯乙烯（PS）共混,通过扫描电镜（SEM）、衰减全反射红外光谱（ATR-FTIR）、X射线衍射（XRD）、拉伸和冲击试验等研究改性胶粉/PS共混材料的结构和力学性能。结果表明,当改性胶粉质量分数为8%时,改性胶粉/PS材料的冲击强度比PS的强度提高了183%,共混材料中改性胶粉以橡胶相分散在PS基体中,二者之间界面粘结良好。     

Effect of graphene on mechanical properties of cement mortars

Functionalized graphene nano-sheets(FGN) of 0.01%-0.05%(mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.     

橡胶粉、粉煤灰对再生砂浆力学性能影响的试验研究

为了更有效地处理及再利用废橡胶和废弃混凝土,对橡胶粉再生砂浆的力学性能进行了试验研究.选取60目精细胶粉与I级粉煤灰直接掺入到再生砂浆中,通过与素再生砂浆、普通砂浆的对比,研究了其对再生砂浆抗折强度与抗压强度的影响,并探讨了橡胶粉和粉煤灰的作用机理.结果表明:橡胶粉掺量为4%、粉煤灰掺量为15%时,有利于改善再生砂浆的力学性能.     

镍铁渣–黏土–水泥改性土力学特性试验及修正的邓肯–张模型

为研究镍铁渣-黏土-水泥(FNSCC)改性土的力学特性,开展了不同镍铁渣掺入比、含水率及养护时间下FNSCC改性土不固结不排水三轴压缩试验;获得了不同工况下FNSCC改性土试样的应力-应变关系曲线及割线弹性模量,分析了其力学特性影响机理及破坏模式,基于试验结果,建立了适用于FNSCC改性土的修正邓肯-张本构模型。研究结果表明：FNSCC改性土的应力-应变曲线具有明显的应变软化特征;其峰值强度随镍铁渣掺入比减小和养护时间增长而增大,随含水率的增加先增大而后减小。随着镍铁渣掺入比的增大,FNSCC改性土试样的破坏模式由鼓胀破坏向剪切破坏转变;含水率为15%左右的试样,鼓胀破坏特别明显;而随养护时间增长,其破坏模式则由鼓胀变形等塑性破坏向局部张裂等脆性破坏转变。FNSCC改性土的割线弹性模量随轴向应变增加而减小,轴向应变小于2%时,镍铁渣掺入比、含水率及养护时间对割线弹性模量的影响较大;而当轴向应变大于2%后,各因素对割线弹性模量的影响很小。修正的邓肯-张模型能较好地反映FNSCC改性土的应变软化现象;该模型中参数m、n及?与围压近似呈线性关系,模型参数m受FNSCC改性土配比的影响最大,养护时间次之,含水率最小。由修正邓肯-张模型计算得到的曲线与实测曲线吻合较好,验证了该模型拟合参数的合理性。