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.

Physical and Mechanical Properties of Crumb Rubber Mortar(CRM)with Interfacial Modifiers

Eight interfacial modifiers were used to improve the interfacial bonding strength between the crumb rubber and matrix of Crumb Rubber Mortar （CRM）, and the physical and mechanical properties and microstructure of CRM were also studied. The results show that, the interfacial modifiers obviously improve the interface bonding strength between the crumb rubber and matrix and the whole strength of CRM, and silicone modified styrene-acryl ate-emulsion has the best effect. The rubber-cement matrix interface was proved by SEM that the interfacial modifiers treated rubber showed good adhesion to the matrix.

Static compressive properties and damage constitutive model of rubber cement mortar with dry-and wet-curing conditions

To investigate the static compressive properties and mechanical damage evolution of rubber cement-based materials(RCBMs) with dry-and wet-curing conditions, uniaxial compression and cyclic loading-unloading tests were carried out on rubber cement mortar(RCM). The mechanical properties of the uniaxial compression specimens cured at 95%(wet-curing) and 50%(dry-curing) relative humidities and cyclic loading-unloading specimens cured at wet-curing were analyzed. Under uniaxial compression, the peak stress loss ratio is higher for dry-curing than for wet-curing. The peak strain decreases with the increase of rubber content, and the peak strain increases with the decrease of curing humidity. Under cyclic loading-unloading, the variation trends of residual strain differences of the normal cement mortar and RCM at each cyclic level with the number of cycles are basically the same, but the failure modes are different. The analysis of the internal mesostructure by a scanning electron microscope(SEM) shows that initial damage is further enhanced by reducing curing humidity and adding rubber aggregate. The damage constitutive model based on strain equivalence principle and statistical theories was used to describe the uniaxial compression characteristics of RCM, and the law of mechanical damage evolution was predicted.

Improved Resistance to Cracking of a Cement Mortar through the Incorporation of Crumb Rubber

Within a context of sustainable development, innovative processes for various applications to recycle rubber are put in place to make aggregates or crumb rubber. These uses include sports floor coverings, to manufacture of sealants, sound absorbing walls, to make roads, as an alternative fuel in cement kilns, etc. In this study, the addition of crumb rubber to mortar was investigated through optical and mechanical tests. The results showed that the incorporation of crumb rubber from used tires into mortar produced a better resistance to shrinkage cracking, but a compressive strength/tensile is reduced. This feature could lend itself to making playgrounds and sports grounds more absorbing and flexible, which would allow a more significant fall to be withstood without injury and consequently enhance the safety of playgrounds.

水泥及胶粉掺量对砂浆拉伸黏结强度的影响

为提高砂浆拉伸黏结强度,研究了不同水泥及胶粉掺量对砂浆拉伸黏结强度的影响。结果表明:当水泥掺量较低时,增加胶粉掺量能在一定程度上提高砂浆的拉伸黏结强度;当胶粉掺量较小时,增加水泥掺量能显著提高砂浆的拉伸黏结强度;当水泥掺量与胶粉掺量均较大时,同时增大水泥与胶粉掺量会降低砂浆的拉伸黏结强度。

聚合物胶粉改性水泥加固砂浆的制备及性能研究

结合特殊工程加固施工需求,采用不同掺量的聚合物胶粉对加固砂浆进行了改性,制备了高性能聚合物水泥加固砂浆,并从工作性、力学性能、黏结性能等方面对其性能进行了研究。结果表明:随着聚合物胶粉掺量的增加,砂浆的可操作时间、凝结时间延长,劈裂抗拉强度增加,抗压、抗折强度降低,但降幅不大;聚合物胶粉的最佳掺量为1.0%,此时对砂浆与钢丝绳的黏结抗剪强度、与混凝土的正拉黏结强度有所改善;自制的加固砂浆具有较好的拉拔强度,且可使混凝土基材内聚破坏,大板模拟试验拉拔测试得到其28 d平均拉拔强度达1.78 MPa,性能良好。

多源固废隔声砂浆的制备及应用研究

通过对比实验和工程应用,探讨废弃橡胶、软木、空心漂珠对再生骨料隔声砂浆工作性能、力学性能和隔声性能的影响,拓展多源固废的综合利用途径。结果表明,橡胶和软木能提高再生骨料隔声砂浆的流动性,但保水率降低;而空心漂珠能同时提高砂浆的流动性和保水性。随着各阻尼材料的掺入,再生骨料隔声砂浆的表观密度、强度显著降低,但仍能满足28 d抗压强度≥5 MPa的要求。橡胶、软木和空心漂珠分别对高、中低和低频段的撞击噪声具有显著改善效果,复掺15%橡胶+15%软木+5%空心漂珠的再生骨料隔声砂浆的综合性能优于单掺的,且较铺设30 mm厚普通砂浆的计权标准化撞击声压级低9 dB。

树脂橡胶改性沥青路面性能研究

为提高公路性能,保证交通安全,提高沥青混合料录用性能,以石油沥青为原料,通过在原料中掺加不同比例的丁苯橡胶和酚醛树脂制备树脂橡胶改性沥青胶浆,通过针入度、软化点、弹性恢复以及布氏黏度试验,试验确定酚醛树脂和丁苯橡胶的最佳掺量分别为3%和4%,并对树脂橡胶改性沥青混合料路用性能进行试验,试验结果表明,在丁苯橡胶改性沥青胶浆中掺入酚醛树脂,可以保证丁苯橡胶改性沥青低温性能的前提下提高改性沥青胶浆的高温性能。

再生橡胶砂浆的力学性能研究

本文旨在添加聚乙酸乙烯酯对再生橡胶砂浆进行改性,解决其在工程实际中容易出现开裂和粘附性能较差等缺陷,从而拓宽再生橡胶砂浆在房屋工程中的应用,进一步缓解废旧轮胎橡胶对生态环境造成的危害。通过一系列的力学实验,研究再生橡胶掺量和聚乙酸乙烯酯掺量对再生橡胶砂浆的流动度、抗折强度、抗压强度和干燥收缩量的影响。结果表明,随着再生橡胶颗粒掺量增加,水泥砂浆的流动度和抗折强度、抗压强度明显降低,降低幅度分别约为37.3%、65.1%和81.4%,试件体积干燥收缩变大,增幅约为61.8%。当再生橡胶掺量一定,随着聚乙酸乙烯酯掺量增多,水泥砂浆流动度和体积收缩量分别增大了31.3%和22.8%,而抗折、抗压强度分别降低了33.1%和45.5%。本文的结论将对再生橡胶砂浆在房屋工程中的应用提供有益的参考价值。

Incorporation of Clay into Natural Rubber (Hevea) for the Production of Tile Adhesive

Natural rubber latex is the white liquid in the form of the colloidal dispersion of rubber globules suspended in the aqueous liquid. Produced in large quantities in Ivory Coast, the local transformation of natural latex has so far remained insignificant, although some attempts have been made to use it in the manufacture of flexible facade briquettes for rounded walls. Thus, this study aims to incorporate clay as a filler in natural latex for use as an adhesive for tile installation. To do this, different proportions of clay paste were added to the natural latex and the resulting mixtures were used to make the sample and tile adhesive. From the analysis of the results obtained, it appears that the samples with a clay paste density of 0.8 and 1 absorb less water and shows good pull-out strength. The mixtures of 30% and 35% latex and 0.8 and 1 clay paste density respectively have pullout stresses greater than 1 N/mm2. According to NF EN 1348, these adhesives can therefore be used as tile adhesive.

基于PSO-BP和GA-BP算法神经网络的锂渣-橡胶砂浆抗压强度预测研究

采用PSO和GA算法优化BP神经网络,建立了3种神经网络预测模型(PSO-BP、GA-BP和BP),通过将不同锂渣掺量、橡胶掺量和养护时间作为神经网络输入层参数,水泥砂浆抗压强度作为输出层参数,并选择RMSE、相关性系数和平均误差来对比分析3种模型对锂渣-橡胶水泥砂浆抗压强度的预测性能。试验结果表明,PSO-BP和GA-BP模型的预测性能均优于BP神经网络,并且PSO-BP预测性能更优异。总体而言,2种算法都可以很好的提高BP模型的预测精度。

双掺氯乙烯-乙烯-乙烯醚乳液与橡胶颗粒改性水泥砂浆的性能研究

采用双掺氯乙烯-乙烯-乙烯醚乳液(PTB乳液)与橡胶颗粒对水泥砂浆进行改性,通过正交试验研究了不同聚灰比、水灰比及减水剂、橡胶颗粒掺量对水泥砂浆抗折强度、抗压强度、折压比、黏结强度和抗渗性的影响。结果表明:抗折强度与抗压强度随聚灰比、水灰比及减水剂、橡胶颗粒掺量变化而变化的规律较为一致,而折压比随着橡胶颗粒的增加而增加,但随着聚灰比、水灰比及减水剂掺量的增加而先增加后减小;黏结强度随聚灰比及水灰比的增加而降低,随减水剂的增加而增加,而随橡胶颗粒含量的变化无明显变化规律;橡胶颗粒的掺入,使砂浆抗渗性明显降低,而少量的PTB乳液即可明显改善其抗渗性。

纤维橡胶砂浆的力学性能与砌体轴压试验

为提高橡胶砂浆的力学性能和适用性,通过单掺聚乙烯醇(PVA)纤维或钢纤维、复掺PVA-钢纤维对橡胶砂浆进行改性,探讨其对超声波传播速度、抗折强度和抗压强度的影响。将普通水泥砂浆、20%橡胶砂浆、复掺PVA-钢纤维橡胶砂浆分别与环保压缩砖结合制作砌体,通过试验研究轴心抗压强度和弹性模量。结果表明:掺入PVA纤维或复掺PVA-钢纤维降低了超声波在橡胶砂浆中的传播速度;掺入PVA纤维或钢纤维提高了橡胶砂浆的抗折强度;复掺一定量的PVA纤维和钢纤维能有效提高橡胶砂浆的抗压强度;20%橡胶砂浆的抗压强度比普通水泥砂浆降低了46%,对应砌体的破坏荷载降低了12.8%;复掺PVA-钢纤维橡胶砂浆的抗压强度比20%橡胶砂浆提高了14.9%,对应砌体的开裂荷载和破坏荷载分别提高了63.4%和4.5%;掺入适量PVA纤维和钢纤维能改善橡胶砂浆的强度明显低于普通水泥砂浆的缺点,将复掺PVA-钢纤维橡胶砂浆应用于砌体工程能改善结构的隔音性,延缓试件的开裂,提高橡胶砂浆砌体的抗压强度。

橡胶沥青混合料抗裂性能影响因素及敏感性分析

通过三点弯曲试验,以冲击韧性作为评价指标,对比分析集料与胶砂体积比(A/M)、温度、橡胶粉掺量3个因素对橡胶沥青混合料抗裂性能的影响规律,并设计正交试验对3个影响因素进行敏感性分析。结果表明:A/M越小试件抗裂性能越好;温度为-15℃、橡胶粉掺量为20%的沥青混合料A/M=0时冲击韧性为5.271 kJ/m^(2),是A/M=1时的2.3倍;相较于70^(#)沥青混合料,橡胶沥青混合料的低温抗裂性能均有所提高;冲击韧性随着温度的降低而减小,温度越低,试件低温抗裂性能越差;A/M=0.4时,橡胶粉掺量30%的沥青混合料当温度为-10℃冲击韧性为3.31 kJ/m^(2),温度降至-20℃时冲击韧性为2.77 kJ/m^(2),降低了16.3%;A/M与温度是影响试件抗裂性能的主要因素。

橡胶粉和硅灰对碱硅酸反应的抑制作用

采用快速砂浆棒法,研究废旧轮胎橡胶粉(WRP)和硅灰(SF)单掺及两者复掺对碱硅酸反应(ASR)引起有害膨胀的抑制作用,并分析WRP粒径对ASR抑制作用的影响;结合扫描电镜和X射线衍射等方法,揭示了两者对活性骨料ASR的抑制机理.结果表明:WRP能够抑制ASR,但其粒径会影响抑制效果,其中0.125 mm (120目) WRP效果最佳;SF对ASR抑制作用早期较好,而后期不够理想;复掺SF和WRP对抑制ASR膨胀协同作用优异,前期SF发生火山灰反应,水化产物具有缚碱能力,有效抑制ASR负面效应,改善了WRP周边砂浆的密实性,后期WRP利用其物理性能降低膨胀压,从而协同缓解了ASR引起的膨胀.

废旧轮胎橡胶粉对水泥胶砂力学性能的影响

本文研究了废旧橡胶粉的粒径(20目、80目、120目)、掺量(2%、4%、6%、8%、10%)对水泥砂浆抗压强度、抗折强度的影响,通过对3 d、7 d、14 d、21 d、28 d抗压强度、抗折强度的对比,结果显示:当橡胶粒径相同时,橡胶粉掺量与水泥砂浆的抗压强度、抗折强度成反比;在橡胶粉掺量相同的条件下,橡胶粉粒径越小,则抗压强度及抗折强度下降越大。

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.

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.

橡胶粉掺量对水泥砂浆性能的影响

选用相同的水泥、水和细集料,通过调节橡胶粉的掺量,配制若干组橡胶粉水泥砂浆,并测定其流动性、强度、韧性及耐磨性能,研究橡胶粉掺量对水泥砂浆性能的影响。结果表明:水灰比相同、橡胶粉按体积比等量取代砂时,水泥砂浆流动度随着胶粉掺量的增大近似线形增加;随橡胶粉掺量的增加,水泥砂浆的7d、28d抗压强度和抗折强度均不断降低;在掺量小于30%之前,韧性和耐磨性能均呈线形增长趋势。

橡胶细集料水泥砂浆基本性能研究

本文研究了橡胶细集料水泥砂浆的基本性能。试验表明橡胶细集料水泥砂浆的抗压强度及抗折强度明显受橡胶细集料掺量的影响。在橡胶细集料的掺量水平大于150kg/m3时,其28天立方抗压强度较普通砂浆降低30%或更多,抗折强度降低则超过20%。但同时发现该掺量水平下砂浆的应力应变特性与普通水泥砂浆相比存在显著不同,其抗折状态下极限拉应变可高达4600×10-6,极限轴压应变超过6000×10-6,凸现了其优越的变形能力,也预示着橡胶细集料水泥砂浆在能量吸收方面的潜力。试验中还发现橡胶细集料水泥砂浆的破坏模式与普通砂浆的脆性破坏模式相比较截然不同,表现出一定的延性破坏特征,由于橡胶细集料的掺入可以明显阻碍裂缝的开展,因此,橡胶细集料水泥砂浆试件能够经历反复加荷破坏过程而仍具有一定承载能力,表现出很高的延性。