混凝土钢筋表面环氧粉末涂料及其性能的研究

优选得到了用于混凝土中钢筋表面的环氧粉末涂料配方，同时对涂料的储存稳定性和物理力学性能。涂层钢筋的弯曲性，少层钢筋与混凝土的握裹强度，加速腐蚀和海港现场暴露试验进行了研究，将倨选粉末涂料与几种国内现有的防腐蚀环氧粉末涂料的有关性能进行了比较。     

钢筋握裹力试验分析

文章对广州某工程实例钢筋握裹力试验方案进行分析,通过实验证明指出带肋钢筋表面虽有氧化皮或局部发泡时,混凝土对带肋钢筋的握裹力没有影响。此依据可为以后实际工作提供参考。     

一种可剥性气相防锈涂料的研制

一般的可剥性涂料成膜后所形成的涂层较脆,不能够大面积剥离,在金属防锈方面比较差,更不具有对金属气相防锈的功能.研制了一种能在常温下快速成膜的可剥性气相防锈涂料,所形成的涂层具有优良的柔韧性和耐冲击强度,能够大面积地进行剥离.提出了涂料的最佳配方为:乙烯基高分子树脂100.0 g,复合型油溶性气相缓蚀剂13.3 g,环氧树脂6101 10.0 g,增韧剂(邻苯二甲酸二丁酯)25 mL,稳定剂(二月桂酸二丁基锡)0.5 g,抗氧剂B215 0.5 g,润滑油2 mL,混合溶剂700 mL.结果表明,这种涂料对金属具有一定的防锈性能和浸泡性能,喷涂于金属表面可有效地提高金属产品的防锈性能.     

SiO2气凝胶对复合隔热涂料性能的影响

以SiO2气凝胶为功能填料,丙烯酸树脂为成膜剂,制备透明隔热涂料。将其涂覆于5mm厚的普通玻璃上制成涂层,并对涂层进行一系列性能测试,包括接触角、红外光谱、光学性能及隔热效果等。结合实验数据分析纳米SiO2含量对复合涂料性能的影响,得出最佳的涂料配方。结果表明,该透明隔热涂料具有良好的化学稳定性和隔热性能,在500W红外灯照射10min时,样品与空白玻璃温差为11℃。     

镁水泥混凝土中钢筋的电化学腐蚀研究

为解决分布在西部盐湖地区出现的煤矿矿区钢材腐蚀问题,结合煤矿矿区实际环境,采用实验、理论分析等方法研究了镁水泥混凝土中钢筋的腐蚀.采用CS350电化学工作站,研究镁水泥混凝土中钢筋的电化学腐蚀,结合SEM微观实验和EDS元素扫描结果,对镁水泥混凝土中裸露钢筋腐蚀状况进行描述.研究表明:美加力涂层钢筋状态良好,未出现腐蚀状态;锌美特涂层钢筋出现了低腐蚀现象;而裸露钢筋表面出现了严重腐蚀.钢筋涂层防腐蚀性美加力涂层较好,锌美特涂层次之;涂层钢筋虽然防腐效果不同,但对裸露钢筋的防腐蚀性能有明显有利影响.     

YJH材料性能及其对混凝土微观结构的影响

为研究YJH渗透结晶材料性能及其对混凝土微观结构的影响,通过在混凝土表面使用不同涂料用量及养护不同时间,分析测试了不同涂层试件的抗渗性能和自修复性能,并通过SEM研究了YJH渗透结晶型材料对水泥砂浆试件微观结构的影响.结果表明:防水涂层可通过催化作用促使未水化的水泥再产生新的晶体,堵塞砂浆孔隙,提高水泥混凝土的抗渗性能,并赋予其自修复功能;当涂料用量为1 kg/m2时,可使水泥混凝土基体的28 d抗渗性能由0.4 MPa提高到1.4 MPa,二次抗渗仍可达到1.2 MPa;涂料的催化结晶作用是长期有效逐渐进行的,经YJH涂料进行涂层处理的水泥混凝土的养护时间越长,其微观结构越密实,防水抗渗性能越好.     

用于多种包装材料的气相防锈涂料的研制

金属表面防腐蚀涂层常常由于较薄、机械强度较差,在使用过程中容易损坏.气相缓蚀剂是一种非接触性的、防锈效果优异的缓蚀剂,而涂料使用非常方便,将二者结合,可以广泛用于各种金属的非接触防锈.在此基础上研制了一种应用于多种包装材料上的气相防锈涂料,提出了该涂料的最佳配方,对该涂料的防锈效果进行了定性和定量加速试验、实地试验和相容性试验.结果表明,该涂料能够应用于多种包装材料,能对所包装的金属产品有长期的防锈作用.     

氯醚防腐蚀涂料的研制及其性能

为了改善传统防腐蚀涂料的性能,自制氯醚树脂并以其为基料,以复合铁钛防锈颜料和云母氧化铁为颜填料制备了氯醚防腐蚀涂料,优化了颜基比、颜填料细度、助剂添加量,并考察了优化条件下制备的涂料的性能。结果表明：随着颜基比的增大,涂层力学性能下降,防腐蚀性能先升高后下降,颜基比为2．00～2．50时涂层的防腐蚀性能最佳;颜填料细度...     

达克罗涂层对氯氧镁水泥混凝土中钢筋防护试验

为了解决盐渍土对普通钢筋混凝土抗盐卤性能较差的问题,结合西部地区基础工程受盐卤腐蚀情况,利用电化学方法,在模拟西部盐卤环境条件下,测试了氯氧镁水泥混凝土中达克罗(DKL)涂层钢筋在氯盐和硫酸盐溶液浸泡环境下的极化曲线,氯氧镁水泥混凝土中的裸露钢筋作为对照组。研究表明,氯氧镁水泥混凝土中的DKL涂层钢筋在氯盐和硫酸盐溶液的腐蚀速率明显小于裸露钢筋,分别可达到裸露钢筋的1/61和1/35,即DKL涂层具有较好的抵抗氯盐和硫酸盐腐蚀的能力,从而可以很好的解决氯氧镁水泥混凝土在西部盐渍土的应用问题。     

石墨烯改性水性丙烯酸树脂涂料的制备与性能

针对现代工业中Cl~-存在的广泛性及危害的严重性,用石墨烯(Gr)改性水性丙烯酸树脂制得涂料,采用正交试验结合电化学测试系统筛选涂料的较优配方,通过可挥发性有机物(TVOC)及甲醛(HCHO)检测、傅里叶红外光谱仪(FTIR)、热重分析(TGA)等分别测试了涂层的环保性能、耐化学品性能、涂层官能团稳定性能、涂层耐热性能。结果表明:当Gr质量分数为0.10%、丙烯酸树脂与交联剂质量比为5∶1、丙烯酸树脂质量分数50.00%、ZnO与Zn_3(PO_4)_2质量比1∶1且总质量分数为7.5%时涂层力学性能较好,涂层耐磨损量和硬度等性能提高了1.5倍以上;涂层固化后TVOC和HCHO释放量远低于国家限制标准;Gr的添加使丙烯酸树脂涂层的耐化学溶剂性、热稳定性和官能团稳定性提高。     

Mix design method for self compacting metakaolin concrete with different properties of coarse aggregate

This study deals with a proposed mix design method for SCC utilizing different properties of coarse aggregate. The work was conducted in three phases, i.e. paste, mortar and concrete to facilitate the mix design process. Initial investigation on cement paste determined the basis for water cement ratio and superplasticizer dosage for the concrete. For the study on mortar, metakaolin (MK) as pozzolan was used at replacement levels of 5%, 10%, 15%, and 20% by weight of cement. Self compactability of mortars was obtained by adding suitable materials such as mineral admixtures and superplasticizer which provided a sufficient balance between flowability and viscosity of the mix. The optimum MK replacement level for cement was 10% from the viewpoint of workability and strength. Flowability of mortar decreased with the use of metakaolin. Moreover, strength of mortar increased when the optimum replacement level of pozzolan was used. Different fresh concrete tests were adopted. The results obtained for fresh concrete properties showed that flowability of concrete increased with increase flowability of mortar. The mixes which contained coarse aggregate with lower volume, small size, and continuous grading affected positively the fresh properties of SCC. Finally, the mix design method used was successful in producing SCC with different coarse aggregate properties.     

阻锈剂对混凝土钢筋氯盐腐蚀行为的影响

过去对混凝土腐蚀的研究,其腐蚀液与实际的混凝土孔溶液有较大的差异。采用水泥提取液模拟混凝土孔溶液,通过自腐蚀电位、动电位极化和电化学阻抗谱研究了Ca(NO2)2及商用阻锈剂NNMI和NNRI对混凝土中钢筋氯盐腐蚀行为的影响。结果表明:3种阻锈剂均能有效降低钢筋受Cl-腐蚀的风险,减小腐蚀速率,并能不同程度地提高钢筋腐蚀的临界Cl-浓度;Ca(NO2)2为阳极型阻锈剂,当[NO2-]/[Cl-]为0.62～1.47时,阻锈效果最好,高达98.2%,NNMI和NNRI为以抑制阴极反应为主的综合型阻锈剂,在推荐掺量下,当环境中Cl-浓度为0.03 mol/L左右时,阻锈效率分别可达到85.0%和87.1%。因此,应根据腐蚀环境状况,选用不同的阻锈剂。     

Application of factorial models to predict the effect of anti-washout admixture, superplasticizer and cement on slump, flow time and washout resistance of underwater concrete

The anti-washout underwater concrete posses different properties from conventional underwater concrete. When an anti-washout admixture is mixed with concrete, the viscosity of the concrete is increased and its resistance to washout is enhanced. Superplasticizer ensures enough concrete fluidity to spread readily in place without vibration. A factorial design was carried out to mathematically model the influence of three key parameters on slump, flow time measured by Orimet and mass loss by washout of underwater concrete. The parameters considered in this investigation were the dosage of cement, the concentrations of anti-washout admixture and superplasticizer. All mixes were made with 0.43 water/cement ratio which correspond a typical underwater concrete. The proposed models are valid for concretes with cement dosage ranging between 420 kg/m³ to 520 kg/m³ and the concentrations of anti-washout admixture and superplasticizer varying between 0.02%–0.13% and 0.4%–1.8%, by mass of cement, respectively. Test results of the models indicated that the slump is highly affected, in order of importance, by dosage of cement and the dosage of superplasticizer, then by the concentration of anti-washout admixture. The mass loss by washout is influenced, in order of significance, by the concentration of anti-washout admixture, the dosage of cement, the concentration of superplasticizer and the interaction between the dosages of cement and anti-washout admixture. The flow time is affected, in order of importance, by the dosage of cement, the concentration of superplasticizer and the interaction between these parameters. This model can be used as a tool to facilitate the test protocol required to optimise the underwater concrete.     

水基切割液防锈剂的复配及其防锈效果

水基切割液钼酸盐防锈剂防锈效率低、对电导率影响大。以油酸、二乙烯三胺合成咪唑啉,经烷基化合成水溶性咪唑啉季铵盐,并与钼酸铵、葡萄糖酸钙一起复配成水基切割液防锈剂。采用电导率仪和电化学方法分析了水基切割液的电导率和腐蚀参数。结果表明:水溶性咪唑林季铵盐和钼酸铵起主防锈作用,葡萄糖酸钙起协同作用;钼酸铵含量对水基切割液电导率的影响最大;水基切割液的最优配比为1 000.0(水基切割液)∶2.0(水溶性咪唑季铵盐)∶1.0(钼酸铵)∶0.1(葡萄糖酸钙);水基切割液呈黄色;45钢在含防锈剂水基切割液中的腐蚀速率为0.240 9 mm/a,缓蚀效率达77.58%,电导率仅增加13.00%。     

Effects of granulated blast furnace slag and superplasticizer type on the fresh properties and compressive strength of self-compacting concrete

This paper presents the results of an experimental investigation carried out to study the effect of granulated blast furnace slag and two types of superplasticizers on the properties of self-compacting concrete (SCC). In control SCC, cement was replaced with 10%, 15%, 20%, and 25% of blast furnace slag. Two types of superplasticizers: polycarboxylate based superplasticizer and naphthalene sulphonate based superplasticizers were used. Tests were conducted for slump flow, the modified slump test, V-Funnel, J-Ring, U-Box, and compressive strength. The results showed that polycarboxylate based superplasticizer concrete mixes give more workability and higher compressive strength, at all ages, than those with naphthalene sulphonate based superplasticizer. Inclusion of blast furnace slag by substitution to cement was found to be very beneficial to fresh self-compacting concrete. An improvement of workability was observed up to 20% of slag content with an optimum content of 15%. Workability retention of about 45 min with 15% and 20% of slag content was obtained using a polycarboxylate based superplasticizer; compressive strength decreased with the increase in slag content, as occurs for vibrated concrete, although at later ages the differences were small.     

基于EIS研究镁水泥混凝土中涂层钢筋的耐腐蚀性

通过模拟室内自然状态、氯化镁溶液和水三种工作环境,采用CS350电化学工作站,结合理论与试验分析,对镁水泥混凝土涂层钢筋的交流阻抗谱进行研究。结果表明:通过对交流阻抗谱和涂层电阻的表征分析得出该涂层可以很好地保护镁水泥混凝土中的钢筋免受腐蚀。不同的混凝土保护层厚度对同时期的涂层电阻有一定的影响,涂层电阻的大小随保护层厚度增加而增加。从而得出该涂层对镁水泥钢筋混凝土中的钢筋起到很好的保护作用,进而解决镁水泥钢筋混凝土在盐渍土地区应用易受侵蚀的问题。     

掺加改性淀粉制备聚羧酸减水剂及其应用

选取经过降解处理的羧甲基淀粉醚(CMS-Na)代替部分异戊烯基聚氧乙烯醚(TPEG)制备一种新型聚羧酸系减水剂(PC2),利用水泥净浆单组分试验得出CMS-Na对TPEG的最佳替代量为15%。另外,用红外光谱(FTIR)对CMS-Na及聚羧酸减水剂的分子结构进行了表征。结果表明,掺加CMS-Na合成的PC2不仅降低了原材料的成本,而且具有良好的分散性和保塑性,同时不影响混凝土强度。     

碳钢用双吗啉甲基脲基复配气相缓蚀剂及其缓蚀性能

目的 制备一种用于碳钢保护的绿色高效复配气相缓蚀剂。方法 以双吗啉甲基脲、尿素、十二烷基磺酸钠为三因素,采用45^#钢为研究对象,通过极化曲线和电化学阻抗实验确定三水平,设计L9(3³)正交实验,筛选出最优配方并制成气相防锈纸,采用X射线光电子能谱和接触角测量研究复方VCI在碳钢表面的吸附情况。结果 筛选出了最佳的三元配方:3 g/L双吗啉甲基脲+2 g/L尿素+0.25 g/L十二烷基磺酸钠;以此为基础制成防锈纸,其挂片实验的缓蚀效率高达94.05%。经该防锈纸防护的金属表面接触角与被原纸保护的金属表面接触角相比增大了约11°,呈现出更高的疏水性。结论 以最优气相缓蚀剂配方为基础制成的气相防锈纸具有明显的气相防锈保护作用。     

KHM170型卧辊磨制备钢渣超细粉工业试验研究

基于KHM170型卧辊磨的钢渣超细粉制备终粉磨工业试验系统,在给定钢渣粉、矿渣粉、水泥熟料粉的质量和粒度范围内,进行用钢渣粉部分代替矿渣粉制作水泥混凝土的强度试验。结果表明,KHM卧辊磨终粉磨系统可以实现钢渣超细粉终粉磨,可用于以热焖渣、滚筒渣为原料制备钢渣微粉的工业化生产;矿渣粉中掺加质量分数不超过30%的钢渣粉,且在满足钢渣粉比表面积大于矿渣粉比表面积和水泥熟料粉比表面积时,可以作为优选的混合材料大量用于混凝土。