硅粉和橡胶颗粒对再生混凝土抗冲磨性能的影响研究

取再生粗骨料取代率为50%,采用硅粉等质量取代水泥和橡胶颗粒等体积取代砂的方式配制再生混凝土,通过试验研究了硅粉掺量及橡胶颗粒掺量对再生混凝土抗冲磨性能的影响。结果表明,随着硅粉掺量的增加,再生混凝土抗冲磨性能提高,掺硅粉再生混凝土的抗冲磨性能优于普通混凝土;随着橡胶颗粒体积取代率的增加,再生混凝土抗冲磨性能逐渐提高,且好于掺硅粉再生混凝土,橡胶颗粒的掺入能够显著提高再生混凝土的抗冲磨性能。     

不同掺合料对水工混凝土抗冲磨性能的影响研究

采用水工混凝土试验规程(DL/T 5150—2001)中混凝土抗含沙水流冲刷试验的标准试验方法(圆环法)和混凝土抗冲磨试验的水下钢球法,研究了混凝土中掺入粉煤灰,HF-粉煤灰,硅粉-粉煤灰,PVA-硅粉-粉煤灰这4种掺合料时,在C9050、C9040两个强度等级下,对于常态混凝土抗冲磨性能的影响。试验结果表明,相同强度等级下,掺入不同掺合料的混凝土抗冲磨性能均较好,硅粉-粉煤灰混凝土和PVA-粉煤灰混凝土的抗冲磨性能优于粉煤灰混凝土和HF-粉煤灰混凝土。     

玄武岩纤维对珊瑚礁砂混凝土抗冲磨性能影响

在复杂的海洋环境下,防波堤等珊瑚礁砂混凝土构筑物发生冲刷磨蚀破坏,为了提高珊瑚礁砂混凝土的抗冲磨性能以及防波堤的耐久性.将不同掺量的玄武岩纤维掺入珊瑚礁砂混凝土,并对其进行单轴抗压、劈裂抗拉和抗冲磨试验,从而得到不同掺量的玄武岩纤维对珊瑚礁砂混凝土的抗冲磨强度,抗压强度和劈裂抗拉强度的影响规律.结果表明:珊瑚礁砂混凝土...     

再生粗骨料和掺合料对再生混凝土抗冲磨性能的影响

采用水下钢球法研究了不同再生粗骨料取代率对再生混凝土抗冲磨性能的影响,并且以再生粗骨料取代率为100%的再生混凝土作为基准混凝土,分别研究单掺粉煤灰、单掺硅灰以及粉煤灰与硅灰复掺对再生混凝土抗冲磨性能的影响。结果表明,随着再生粗骨料取代率的增加,再生混凝土的抗冲磨性能显著降低;粉煤灰的掺入降低了再生混凝土的抗冲磨性能;硅灰能够明显地提高再生混凝土的抗冲磨性能;粉煤灰和硅灰不同的复掺比例对再生混凝土的抗冲磨性能影响不同,复掺硅灰5%+粉煤灰15%再生混凝土的抗冲磨性能优于基准混凝土。     

减缩剂与膨胀剂对水工混凝土性能的影响

通过试验,对比研究了减缩剂和膨胀剂对水工混凝土基本力学性能、自身体积变形、抗冲击韧性、抗冲磨强度和抗裂性能的影响。结果表明,掺入SBT-SRA减缩剂后,虽然混凝土强度、极限拉伸值均有所降低,但可抑制混凝土的干缩、自生体积收缩,对混凝土平板抗裂性有利;掺入ZY-UEA膨胀剂时,混凝土180 d的极限拉伸值与抗拉强度均存在倒缩现象,自生体积的后期收缩超过基准混凝土,且同龄期混凝土抗冲磨强度的降低幅度可达20%左右。     

生态纤维对水工混凝土抗冲磨性能影响的试验研究

对掺加生态纤维、硅粉、粉煤灰和减水剂的高性能混凝土进行抗冲磨性能试验,结果表明生态纤维能够明显地提高混凝土的抗冲磨性能,对流动性和抗压强度有降低作用,但影响较小。     

珊溪工程抗冲磨高性能泵送钢纤维混凝土的研究和应用

本文介绍了珊溪水利工程用抗冲磨高性能泵送钢纤维混凝土的研究和应用,内容包括:不同强度、不同钢纤维掺量对钢纤维混凝土各项物理力学性能及抗冲磨性能的影响;C40硅粉钢纤维混凝土的各项性能研究以及现场工程应用取样结果.     

冲磨速率和角度对海工混凝土抗冲磨性能的影响

针对海水挟砂浪涌的服役环境,试验研究了冲磨速率及冲磨角度对桥梁墩柱海工混凝土抗冲磨性能的影响,并对不同胶凝材料体系混凝土抗冲磨强度进行了比较.结果表明：冲磨速率和冲磨角度对海工混凝土抗冲磨性能有较大影响.在胶凝材料体系不变的前提下,海工混凝土稳定磨损率随冲磨速率增大逐渐增大,抗冲磨强度随冲磨速率增大逐渐降低;海工混凝土稳定磨损率随冲磨角度增加逐渐增大,当冲磨角度小于60°时,稳定磨损率增加速率较大,超过60°后增加速率趋缓,当冲磨角度为90°时,稳定磨损率最大.在相同强度等级条件下,硅粉对混凝土抗冲磨强度的贡献最大,而矿粉与粉煤灰复掺也显著提高了混凝土的抗冲磨强度.     

钢纤维硅粉砼的冲磨冻融试验研究与工程应用

本文对钢纤维硅粉砼的抗冲磨、抗冻融性能进行了室内试验,并通过对钢纤维硅粉砼冻融过程中抗压、抗弯强度和弯曲韧性指数的计算,以及动弹性模量、失重率变化的测量,得到了其冻融过程中的宏观特性.水砂冲刷试验反映了钢纤维硅粉砼的抗冲磨性能.大量试验表明:钢纤维硅粉砼具有良好的抗冲耐磨能力和抗冻融破坏性能.作者分析了钢纤维硅粉砼抗冲刷耐冻融性能的细观机理,介绍了钢纤维硅粉砼在水工建筑物某些部位的应用情况,可供有关工程应用参考.     

HLC-GMS特种抗冲耐磨聚合物钢纤维砂浆的性能研究

利用丙烯酸酯共聚乳胶粉与超微细粉、超细钢纤维、高性能减水剂和特种骨料与水泥经特种工艺复合而成的HLC-GMS特种抗冲耐磨聚合物钢纤维砂浆具有高强、高抗冲磨、高黏结性能,砂浆28 d抗压强度大于100 MPa,抗折强度大于20 MPa,抗冲磨强度大于20 h(/kg/m2)(钢球法),抗拉强度大于7 MPa,是水工建筑物过流面防护和修补缺陷的新型高性能抗冲耐磨材料。     

纳米CaCO3对混凝土抗冲磨性能影响试验研究

试验研究了不同掺量纳米CaCO3对混凝土力学性能和抗冲磨性能的影响,并通过水化热测试方法研究了纳米CaCO3对混凝土性能影响的机理。试验结果表明,适量的纳米CaCO3可以提升混凝土的力学性能,提高混凝土的抗压强度、劈裂抗拉强度和抗冲磨性能。当纳米CaCO3的掺量为1.5%时,混凝土抗冲磨强度提高约6倍;纳米CaCO3促进了水泥的水化反应,改善了水泥浆体微观结构,提升了整体的密实性。     

Evaluation of destruction specific energy of fly ash and slag admixed concrete interlocking paving blocks (CIPB)

Concrete interlocking paving blocks (CIPB) are widely used in flooring and covering applications such as city roads, pedestrian foots, gardening architecture and many surface coverings. The focus of this study is to evaluate destruction specific energy (SE_des) of CIPB containing fly ash and blast-furnace slag at different curing conditions. The SE_des is estimated from the area (integral) under stress–strain envelope for an unconfined compression test. This method provides a better understanding between performance and the main mechanical character of CIPB. Compressive strength, splitting tensile and flexural tensile strengths, rebound hardness and abrasion resistance tests at 3, 7, 28, 90 and 180 days were carried out. The test results showed that fly ash (FA) and blast-furnace slag (BFS) can replace the cement by amounts of 10–20%, 30–40% of mass, respectively. This helps to produce CIPB with lower cost and better engineering properties. The relationship between SE_des, strength, hardness and abrasion are defined for CIPB.     

Usage of industrial by-products to produce plain concrete elements

This paper describes the results of research aimed at studying the possible usage of bottom ash (BA) and granulated blast-furnace slag (GBFS) in production of plain concrete elements. Sufficient number of briquettes, paving blocks and kerbs specimens containing GBFS and BA as fine aggregate replacement were produced in laboratory. Then, some of tests were conducted for investigating durability and mechanical properties of these specimens. Unit weight, compression strength and freeze–thaw tests were conducted for briquette specimens. Compression strength, freeze–thaw, water absorption and surface abrasion tests were conducted for paving blocks. Surface abrasion and flexural tensile strength tests were conducted for kerb specimens. While compression strength was decreased slightly, durability characteristics such as resistance of freeze–thaw and abrasion were improved. The results showed that usage of partially fine aggregate of these industrial by-products has more beneficial effects on durability characteristics of plain concrete elements.     

粉煤灰品质对路用混凝土耐磨性的影响分析

混凝土耐磨性是混凝土路面表面功能的重要保证,其中掺加粉煤灰是改善道路混凝土耐磨性的重要措施。在基准混凝土中掺加不同品质的粉煤灰,检测了各混凝土的不同龄期的强度、耐磨性能随其掺量用量的变化规律,并探讨了粉煤灰改善混凝土耐磨性的机理。结果表明:掺加I级粉煤灰对路用混凝土强度和耐磨性的改善效果较掺加II级粉煤灰好;粉煤灰混凝土早期强度和耐磨性较差,而后期磨耗损失量明显降低;粉煤灰混凝土强度与耐磨性之间不存在很强的相关性。     

钢渣微粉对混凝土路用性能的影响

研究了钢渣微粉对混凝土路用性能和抗冻融循环能力的影响.结果表明:掺钢渣微粉可使混凝土路用性能和抗冻性能大幅提高,当钢渣微粉掺量为10%(质量分数)时,其抗折强度比普通基准混凝土提高约30%,脆度系数降低30%,耐磨性能提高13%以上.     

Evaluation of fiber reinforced nanostructured perlite-cementitious surface compounds for building skin applications

The effect of short polypropylene (PP) fiber loading on the fracture resistance and indirect tensile strength of nanostructured perlite-cementitious surface compounds (NPCSC) is studied. Loadings of 1%, 2%, 3% and 4%, by weight, of short PP fiber were added to the control mix. An increase of 34% in the indirect tensile strength was achieved at a PP fiber loading of 2% by weight. A fourfold increase in the fracture resistance was achieved at a fiber loading between 3% and 4%. Siding panels 1.6 cm thick was constructed and no cracking was observed after 6 months in the fiber reinforced panels, while cracks emanating from the outer edges of the panels without PP fibers were observed.     

轻骨料混凝土耐磨性影响因素的研究

采用正交设计的方法,研究水灰比、骨料粒径和浆骨比这三种因素对轻骨料混凝土强度和耐磨性的影响规律。在此基础上,进一步研究了粉煤灰、含气量对轻骨料混凝土强度和耐磨性的影响。试验结果表明:水灰比是影响轻骨料混凝土强度的最主要因素,骨料粒径是影响耐磨性的最主要因素。粉煤灰掺量在10%~15%,轻骨料混凝土的后期(56d)强度和耐磨性明显提高。含气量大于4.4%时,轻骨料混凝土抗压强度明显下降;含气量大于3.3%后,耐磨性明显下降。     

Abrasion resistance of concrete containing SiO2 and Al2O3 nanoparticles in different curing media

In the present study, abrasion resistance and compressive strength of concrete specimens containing SiO₂ and Al₂O₃ nanoparticles which are cured in different curing media have been investigated. Portland cement was partially replaced by up to 2.0 wt.% SiO₂ and Al₂O₃ nanoparticles and mechanical properties of the produced specimens were measured. Increasing the nanoparticles content have found to increase the abrasion resistance of the specimens which were cured in water and saturated limewater, while this condition was not observed for compressive strength in both curing media. The enhancement of abrasion resistance was more for the specimens containing SiO₂ nanoparticles in both curing media. Since, abrasion resistance and compressive strength of the specimens follow a similar regime by increasing the nanoparticles content when they are cured in saturated limewater, some experimental relationships has been presented to correlate these two properties of concrete for this curing medium. On the whole, it has been concluded that the abrasion resistance of concrete does not only depend on the corresponding compressive strength.     

Influence of class F fly ash on the abrasion–erosion resistance of high-strength concrete

This study investigates the abrasion–erosion resistance of high-strength concrete (HSC) mixtures in which cement was partially replaced by four kinds of replacements (15%, 20%, 25% and 30%) of class F fly ash. The mixtures containing ordinary Portland cement were designed to have 28 days compressive strength of approximately 40–80 MPa. Specimens were subjected to abrasion–erosion testing in accordance with ASTM C1138. Experimental results show that the abrasion–erosion resistances of fly ash concrete mixtures were improved by increasing compressive strength and decreasing the ratio of water-to-cementitious materials. The abrasion–erosion resistance of concrete with cement replacement up to 15% was comparable to that of control concrete without fly ash. Beyond 15% cement replacement, fly ash concrete showed lower resistance to abrasion–erosion compared to non-fly ash concrete. Equations were established based on effective compressive strengths and effective water-to-cementitious materials ratios, which were modified by cement replacement and developed to predict the 28- and 91-day abrasion–erosion resistance of concretes with compressive strengths ranging from approximately 30–100 MPa. The calculation results are compared favorably with the experimental results.     

道路高性能混凝土耐久性研究与应用

从耐磨性、干缩、抗裂性等方面,研究了粉煤灰、矿渣两种矿物掺合料对道路高性能混凝土性能的影响,并初步探讨了其影响机理.研究结果表明:掺入质量分数为20%～40%粉煤灰和矿渣的道路高性能混凝土具有工作性好、后期强度高、耐磨、低收缩以及抗裂性好等特点.工地应用表明,用粉煤灰与矿渣复合双掺配制的道路高性能混凝土可显著改善路面的路用性能.