羧酸型减水剂与水泥的相容性研究

选用含有亲水性羧基、酸酐基、磺酸基、聚环氧乙烷侧链的单体共聚合成了3种羧酸型减水剂,针对4种不同产地的P.O 42.5水泥,测定了在较低水灰比(mw/mc=0.29)下水泥净浆流动度及30 min经时变化,混凝土坍落度及180 min经时变化.净浆流动度30 min损失小于13.8%,混凝土坍落度60 min损失小于15%.3种羧酸型减水剂与不同水泥均具有良好的相容性.     

水泥与液态高效减水剂的相容性研究

通过水泥净浆流动度试验,分析了5种常用液态高效减水剂与3种水泥之间的相容性,结果表明：5种减水剂对于3种水泥的相容性均表现出很好的一致性。聚羧酸系减水剂与所有水泥均表现出良好的相容性,减水剂的相容性受水泥细度的影响显著。     

水泥与高效减水剂相容性问题研究

不同的水泥和高效减水剂之间相容性差别很大，这是现代混凝土生产和 施工中常遇到的问题。本文从不同角度分析和探讨水泥与高效减水剂相容性的问题，并提出改善水泥和高效减水剂相容性的一些途径。     

粉煤灰对水泥与减水剂相容性的影响研究

影响混凝土外加剂与水泥相容性问题的因素很多,混和材的种类和掺量是其中之一。以减水剂为例,其在水泥混凝土应用中存在饱和点,通过饱和点的变化可判定水泥与减水剂的相容性好坏,采用不同混和材掺量、不同高效减水剂掺量的水泥净浆试验,进行5 min、30 min、60 min的净浆流动度的测试及饱和点的确定,结果表明,加入混合材后改善了水泥与高效减水剂之间的相容性,少量粉煤灰可以提高浆体的初始流动度,改善流动度经时损失。     

聚羧酸系外加剂与水泥的相容性研究

笔者在本文中,对聚羧酸系外加剂与水泥相容性做了具体分析,通过研究水泥的碱含量、掺入量和细度等对聚羧酸系外加剂的相容性。在探讨混凝土配合比设计与试验的基础上,合理确定了水泥对聚羧酸系外加剂相容性的规律,进而得出相关的结论为,JX-5聚羧酸系外加剂与水泥的相容性良好。     

水泥和矿物掺合料与减水剂相容性问题的试验研究

通过试验,研究了两种新型高效减水剂与水泥和3种矿物掺合料的相容性,并就矿物掺合料的合理掺量和复合使用问题进行了初步讨论.     

减缩剂与减水剂的相容性研究

研究了两种减缩剂与四种减水剂复合后对溶液表面张力、混凝土坍落度、混凝土强度、混凝土自由收缩和砂浆收缩的相容性问题.试验结果表明,两种自身表面张力相近的减缩剂对蒸馏水和减水剂溶液表面张力的作用差异较大,但对砂浆和混凝土的减缩率几乎相同,收缩规律的影响相似,说明表面张力并不是减缩率的惟一决定因素.就减缩率而言,减缩剂与减水剂的相容性是较好的,而对强度的相容性相对较差,其作用机理与减水剂分子的支链数及负离子基团数有关.     

固硫灰-钛矿渣复合掺合料与萘系减水剂的相容性研究

通过考察固硫灰-钛矿渣掺入水泥-减水剂体系后,浆体的Marsh时间、经时损失及减水剂饱和掺量,研究了固硫灰-钛矿渣对水泥与减水剂相容性的影响。结果表明:随着原状固硫灰/钛矿渣的增加,减水剂饱和点掺量和浆体5min的Marsh时间均增加,但60min饱和掺量点处浆体的Marsh时间经时损失变化不明显;磨细固硫灰替代原状固硫灰,可有效改善粉料体系与减水剂的相容性,这主要得益于磨细固硫灰颗粒孔结构的改善。     

水泥与高效减水剂适应性的试验研究

通过对普通硅酸盐水泥、矿渣硅酸盐水泥与GK-3000、HJ-12、萘系FDN三种高效减水剂的适应性进行试验研究,在不同品种水泥中掺入不同品种不同用量的高效减水剂,测其减水率及3 min、30 min和60 min后的流动度、坍落度值,得出普通硅酸盐水泥与萘系FDN高效减水剂间适应性良好的结论,并测得该减水剂的平均减水率为19.8%。     

The Compatibility of Polycarboxylate-Type Superplasticizers with Cement

Four polycarboxylate- type （ PC ） superplasticizers of different functional groups were used ; their dispersing and retaining behaviors were analyzed through ZETA potential measurement, mini-slump test of cement paste and performance test of concrete. The experimental results show that the dispersing and flow-retaining ability of PC was determined by two factors of anionic groups and nonionic groups ： the density of anionic groups - COO^- or - SO3^- acted on the electronic repulsive force. and the length and proportion of nonionic graft groups of PEO in PC chemical stracture affected the steric effect. The compatibility between PC superplasticizers and cement mainly depended on the type of PEO groups ; furtlwrmore, adding mineral powders is good to the compatibility for high performance concretes （ HPCs ）.     

聚羧酸系高效减水剂PC的合成及性能研究

以甲基丙烯酸、聚乙二醇1000、对甲苯磺酸、对苯二酚、过硫酸铵和甲基丙烯磺酸钠为原料,采用两步法合成出新型聚羧酸系高效减水剂(简称PC)。将合成的PC与目前广泛使用的萘系高效减水剂(简称FDN)相比,具有更加优异的性能,具体表现为:在掺量很少情况下,水泥净浆就具有较高的流动度;当掺量相同时,其对水泥净浆流动度远超FDN。此外,它与水泥的相容性好,具有缓凝及明显抑制水泥净浆流动度经时损失性能,对混凝土也能表现出显著的减水增强性,是一种性能优良,适合于配制高强、超高强混凝土的高效减水剂。     

Influence of Superplasticizers on Strength and Shrinkage Cracking of Cement Mortar under Drying Conditions

The effects of polynaphthalene series superplasticizers（PNS） with a low content of sodium sulfate （H-UNF）,with a high content of sodium sulfate（C-UNF） and polycarboxylate type superplasticizer （PC） on strength and shrinkage cracking of cement mortar under drying conditions were investigated by means of multi-channel ellipse ring shrinkage cracking test, free shrinkage and strength test. The general effect of PNS and PC is to increase the initial cracking time of mortars, and decrease the cracking sensitivity of mortars. As for decreasing the cracking sensitivity of mortars, PC〉H-UNF〉C-UNF. To incorporate superplasticizers is apparently to increase the free shrinkage of mortars when keeping the constant w/b ratio and the content of cement pastes. As for the effect of controlling the volume stability of mortars, PC〉C-UNF〉H-UNF. Maximum crack width of mortars containing PC is lower, but the development rate of maximum crack width of mortars containing H-UNF is faster in comparison with control mortars. The flexural and compressive strengths of mortars at 28-day increase with increasing superplasticizer dosages under drying conditions. PC was superior to PNS in the aspect of increasing strength.     

基于截面特征相容的曲面约束重构

为了从点云中重建高品质的曲面模型,提出一种基于截面特征相容的曲面重构方法.该方法将由点云切片获取的截面曲线分层次表达为直线、圆弧、B样条等基本曲线元和特征点的集合,并基于曲线微分几何属性,建立截面曲线特征点对应的数学模型,采用动态规划法求解并确定其初始对应关系,以曲线元特征匹配准则优化对应,逐步确立截面曲线间的特征对应关系,将特征对应关系映射为参数对应即可利用成熟算法逼近生成蒙皮曲面.实例表明,该算法获取的曲面模型不但满足精度和光顺性要求,而且忠实地反映了原始物理样件所蕴含的特征信息.     

新型含镁铝尖晶石的铝酸盐水泥的研究

以白云石和工业三氧化二铝为原料，采用反应烧结技术制得了含镁铝尖晶石的铝酸盐水泥，探讨了原料及烧结温度和添加剂对含镁铝尖晶石的铝酸盐水泥性能的影响，XRD结果表明产物的物相组成为MA，CA，CA2；采用扫描电镜（SEM）及能谱（EDS）对产物的显微结构进行了观察与分析。结果表明：以轻烧白云石和工业Al2O3为原料制得的水泥具有较高的结合强度；所制得的含镁铝尖晶石的铝酸盐水泥的显微结构较为均匀，外加剂CaCl2具有明显的早强效果。     

Effect of superplasticizers on the early age hydration of sulfoaluminate cement

The effects of two types of superplasticizers on the properties of CSA cement pastes during early hydration were studied. The influences of two types of superplasticizers on the properties of cement pastes, including the normal consistency, setting time, fl uidity, and compressive strength, were investigated by using various methods. The hydration products of the cement pastes cured for 1 day and 3 days were studied by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results show that the PCE type superplasticizer retards the early age hydration while the FDN type superplasticizer accelerates the early age hydration of the CSA cement. Both types of superplasticizers have no infl uence on the further hydration of CSA cement, confi rmed by the calorimeter tests as well. The ultrasonic pulse velocity measurements were used to probe the influence of two types of superplasticizers on the hydration of CSA cement pastes at a high water-cement ratio（0.45）. The results show that the PCE type superplasticizer retards the early age hydration of the CSA cement while the FDN type superplasticizer has little infl uence on the early age hydration of the CSA cement.     

纤维素衍生物增塑体系溶剂化研究

目的　研究纤维素衍生物与低分子体系溶剂化程度对热力学相容性影响 .方法　对增塑体系组分间热力学相容性进行理论分析并通过实验测试 .结果　建立了半刚性链纤维素衍生物增塑体系组分相容性界限与溶剂化参数间关系 .结论　在溶剂化状态下 ,影响纤维素衍生物增塑体系热力学相容性的主要因素是溶剂化程度 ,而溶剂化程度与小分子、纤维素衍生物中葡萄糖环基摩尔体积比值 V1 / V2 和溶剂化参数 z值有关 .     

运输枢纽与物流活动的相容性研究

运输枢纽与物流业在发展过程中既有密切的关联,又存在一定的不协调性.运用数量分析的方法,对运输枢纽与物流活动的相容性进行评价分析,以寻求一种合理且实用的方法对两者间在发展过程中的相容与不容进行客观地评价和判断.