膨胀剂WHU对自密实砼收缩及渗透性的影响

高强自密实混凝土既要解决高强度要求采用的超低水胶比、高强胶结材料或者高的胶结材用量等配制技术与大流动性之间的突出矛盾。又要解决容易出现的收缩增大问题，采用具有与水泥收缩规律针对性更强的新型多元复合膨胀剂WHU，能够产生比一般膨胀剂持久的后期膨胀，使最终的体积稳定性得到明显改善，抗渗性提高，研究了WHU对工作性、强度、渗透性和体积稳定性的影响规律。     

复合外掺料对高性能水泥胶砂性能的影响

以低水胶比高强度水泥胶砂为研究对象,初步探讨了高效减水剂、矿渣、粉煤灰、膨胀剂、高吸水树脂及聚合物纤维等组分构成的复合外掺料对水泥基材料的工作性、早期自收缩和力学性能的影响.通过试验结果的对比,发现同时掺入高效减水剂、矿渣、粉煤灰、膨胀剂和高吸水树脂的水泥胶砂流动性最好,流动度经时损失最慢,早期自收缩最小,同时早期力学性能较好.聚合物纤维的掺入有效地提高了水泥胶砂的韧性和体积稳定性.     

纤维混杂与微膨胀复合对FRCC抗渗性能的影响及其机理

本文采用双重和多重复合的技术途径，研究了纤维、纤维混杂及其与微膨胀复合对纤维增强水泥基复合材料(FRCC)抗渗性能的影响。实验结果表明纤维混杂及膨胀剂的引入均使FRCC的抗渗性能有所提高，其微观机理本文亦作了一些初步探讨。     

GL-D多功能微膨胀剂性能研究

主要研究了GL－D微膨胀剂的水泥净浆膨胀、水泥胶砂膨胀和混凝土膨胀及其他性能,并简要阐述了该膨胀剂的水化机理。研究结果表明,GL－D多功能微膨胀剂掺量低、碱合量低,性能优良。     

无机矿粉对碱激发碳酸盐胶凝材料性能的影响

研究了矿渣、粉煤灰和偏高岭土时碱激发碳酸盐胶凝材料的强度、抗渗性能以及凝胶时间的影响，探讨了该材料浆体的流变特性。研究表明：1)矿渣可大幅度提高该材料的强度和抗渗性能，但会显著缩短凝胶时间；偏高岭土有利于强度的提高，但时抗渗性能和凝胶时间的影响不显著；粉煤灰时这些性能的影响均不显著；2)无机矿粉复合后，可使材料28d的抗压强度达43MPa以上，抗渗压力达1.5MPa以上；3)该胶凝材料的浆体为宾汉型流体；4)该胶凝材料中掺加粉煤灰，其浆体的流动性优于掺加矿渣和偏高岭土的浆体流动性。     

球墨铸铁用硅钙钡复合孕育剂的研究

对比研究了７５Ｓｉ－Ｆｅ，Ｓｉ－Ｃａ和Ｓｉ－Ｃａ－Ｂａ复合孕育剂对铸态球铁金相组织和机械性能的影响．试验结果及检测分析表明，Ｓｉ－Ｃａ－Ｂａ复合孕育剂的加入，增加了球铁单位面积上的石墨球数，改善了石墨球的圆整度、尺寸和分布的均匀性；同时，提高了球铁基体中的铁素体含量；在保持球铁强度不变的条件下，明显地提高了球铁的延伸率．     

SF—A型混凝土养护剂的研制及应用

研制开发了SF－A型混凝土养护剂，该养护剂由无机和有机材料复合而成，保水性能好，代替传统养护方法能减少混凝土表面早期裂缝，提高混凝土强度和抗渗性，从而提高混凝土工程质量。     

苯乙烯异戊二烯三元嵌段共聚物／异戊橡胶／氯丁橡胶共混物的研究

有秒同方法研究了聚乙烯异戊二烯三元嵌段共聚物／异戊橡胶／氯丁橡胶三元共混体系的相态结构与力学性能，结果表明ＳＩＳ作为相容剂，适量地加入（３￣７份）将明显促进分散相粒子的分布，提高了硫化胶拉伸强度，改善了应力－应变性能。     

纤维混杂与微膨胀复合对FRCC抗渗性能的影响及其机理

本文采用双重和多重复合的技术途径,研究了纤维、纤维混杂及其与微膨胀复合对纤维增强水泥基复合材料(FRCC)抗渗性能的影响。实验结果表明纤维混杂及膨胀剂的引入均使FRCC的抗渗性能有所提高,其微观机理本文亦作了一些初步探讨。     

JMP防水密实剂研究

JMP防水密实剂是一种多功能的复合外加剂。能改善混凝土(以下混凝土简写为砼的)和易性,提高砼的强度,提高抗裂抗渗等性能。该产品具有生产工艺简单、施工方便、成本低廉、是地下防水砼的理想外加剂。     

薄壁结构C50抗渗防裂混凝土试验

根据薄壁结构混凝土的特点，利用中热硅酸盐水泥优化设计出了C50抗渗防裂混凝土配合比。试验结果表明：聚丙烯纤维、钢纤维通过单掺或混掺配制的混凝土28d抗压强度均达到56MPa，抗渗等级P12，满足混凝土的抗渗防裂要求；且单掺聚丙烯的纤维混凝土表现出更优异的抗渗透能力和抗裂性能。SEM微观结构显示，掺膨胀剂混凝土中的水泥石结构均匀密实，产生的钙矾石水化产物丰富，对水泥石收缩具有明显补偿作用，提高了薄壁结构混凝土的抗渗防裂能力。     

Self-healing of cracks in concrete with various crystalline mineral additives in underground environment

Cracks can deteriorate mechanical properties and/or durability of concrete. A few studies have shown that, cracks can autogenously heal under a certain conditions besides the traditional passive repair with a deliberate external intervention. For underground concrete structures, the presence of water, as a necessity for chemical reactions of the healing additives, is beneficial to healing concrete. In this paper, a natural healing method by mineral additives was developed according to the chemical and physical characteristics of underground environment. The healing capacity of three different crystalline mineral materials classified namely, carbonate, calcium sulphoaluminate expansive agent and natural metakaolin due to permeation- crystallization, expansion and pozzolanic reaction, has been assessed from the mechanical properties, referring to the relative elastic modulus, the strength restoration, and the water permeability of the healed specimens. In addition, the morphology of the healing products in the vicinity of the crack was observed. The results indicate that the specimens incorporated with the three mineral additives show different healing capacity according to the improved mechanical properties and permeability. The permeability of the host matrix decreased a lot after crack healing by natural metakaolin followed by carbonate whereas no noticeable improvement of water permeability has been observed for the specimens mixed with expansive agent. The specimens incorporated with carbonate show the best mechanical restoration in terms of relative elastic modulus and compressive strength. Although the dominate element is CaCO3 by reaction of CO32-, either from the dissolved CO2 or from the additives, and Ca2＋ in the cementitious system to fill the cracks, the healing capacity depends greatly on the morphology and the properties of the newly formed products.     

Effects of Curing Condition on the Carbonation of Shrinkage-compensated Concrete

Shrinkage-compensating concrete can enhance the permeability and strength. In addition,expansive admixture can densify concrete to advance the carbonation resistance ability. Due to special quality of ettringite,the relative humidity of curing environment has significant effect on the carbonation rate of concrete. This paper discusses the influence of environmental humidity on carbonation rate of shrinkage-compensating concrete. Four different curing conditions were set up,namely the natural environment (RH 60%),standard environment (RH 90%),early age water curing environment for 3 d and 7 d. After curing in these four environments for 28 d,an accelerated carbonation test was performed. Micro-hardness analysis was used to evaluate surface hardness,which depends on,to a great degree,the carbonation depth. TG-DSC analysis was used to study Ca(OH)2 content gradient in the surface layer of concrete in different environment. The results show that natural condition lead to a relatively worse carbonation degree,curing in water for 3 d is harmful to the carbonation resistance,while curing in water for 7 d lead to an equivalent carbonation degree with standard condition,which show the most improvement to carbonation resistance ability.     

Effect of combination of steel fiber and MgO-type expansive agent on properties of concrete

The effect of combination of steel fiber and MgO-type expansive agent (MEA) on strength, air-permeability and porosity of concrete was investigated. The porosity and air-permeability of concrete were determined by method of evaporated water and Torrent permeability tester, respectively. Pore structures of mortars in concrete were analyzed using mercury intrusion porosimetry (MIP). Interfacial structures between steel fibers and matrix were examined by use of optical microscope. The experimental results show that improvement of pore structures of mortar and fiber-matrix interfacial structure in concrete by combination of steel fiber and MEA may remarkably increase properties of concrete. In comparison with plain concrete, compressive strength and splitting tensile strength of steel fiber reinforced expansive concrete increased by 15.3% and 38.1%, permeability coefficient K _t, penetration depth L and porosity of concrete decreased by 41.1%, 21.3% and 13.1% at 28 days, respectively.     

贝壳改良膨胀土的抗剪强度试验研究

针对膨胀土遇水膨胀失水收缩的问题,将贝壳碾碎添加到膨胀土中,通过系统的室内抗剪强度试验,探讨贝壳改良膨胀土的强度变化规律。试验结果表明:掺入贝壳能够有效提高膨胀土的抗剪强度,随着贝壳掺量的提高,抗剪强度先增大后减小,12%贝壳掺量时,改良土的抗剪强度达到最大。     

Internal curing using water-releasing material for high strength micro-expansive concrete

Due to its low water content, it is difficult for expansive agent to have an effective expansive effect on high strength concrete to compensate its extensive shrinkage and form a certain expansion. To solve this problem, water-releasing material with water storage and releasing characteristics was incorporated into high strength micro-expansive concrete to provide internal curing, and expansive effect of expansive agent was improved. Migration of water from initially saturated water-releasing material to the surrounding hydrating cement paste was investigated. Based on a given efficient diffusion distance of water stored in water-releasing material, the mass and real water-cement ratio of cured cement paste were estimated. At the same time, the effect of internal curing of water-releasing material on the volume deformation of high strength micro-expansive concrete was investigated. Funded by the Project of National Natural Science Foundation (No. 50508034) and Guangxi Key Laboratory for the Advance Materials and New Preparation Technology(No. 063006-5C-13)     

高密实混凝土技术路线与性能研究

探讨了高密实混凝土技术路线与性能。依据骨料密实堆积的理论，利用粗细骨料与粉煤灰按照大小粒径致密堆积在一起，获得混凝土中骨料间的最小空隙Vv，再利用Vv来控制混凝土中的浆体用量Vp，从而达到减少混凝土中水泥用量和单位用水量的目的。高密实混凝土因为骨料颗粒搭配情况良好，密实堆积，这有助于减少骨料之间的滑动阻力，在高效减水剂的作用下，拌制出高流动性、易泵送的混凝土。同时，只需少量水泥浆，致密堆积混凝土的设计强度通过骨料间传递应力即可达到。     

Preparation of High Impermeable and Crack-resistance Chemical Admixture and Its Mechanism

A kind of high impermeable and crack-resistance chemical admixture ( HICRCA ) was prepared, which is a compound chemical admixture composed of an expansion ingredient, density ingredient, and organic hydrophobic poreblocking ingredient. The results of the experiments indicate that the addition of HICRCA improves mortar and concrete in the following performances: ( 1 ) perfect workability: slump is more than 22cm, the slump after 3 h is about 16cm; (2) high impermeability.for the mortar, the pervious height under a water pressure of 1.5MPa is 1.5cm,for the concrete, the pervious height under a water pressure of 5.0MPa is 2.2cm; (3) high crack-resistance:there is a micro-expansion at the age of 9Od ; ( 4 ) high compressivestrength : compared with the controlled concrete, the compressive strengths at the age of 3d and 28d are improved by 66.4% and 62.0%, respectively. At the same time, the effects of different curing condigon on mortar and concrete expansive and shrinkage performance were studied. In addition, the impermeable and crack-resistance mechanism was investigated in the present paper.     

约束膨胀混凝土显微结构分析

有钢管对膨胀混凝土形成三向约束,采用扫描电镜（ＳＥＭ）,研究约束膨胀混凝土的显微结构与普通混凝土显微结构的差异,进而揭示约束膨胀混凝土的显微工程机理。实验证明：由于约束膨胀的填充作用,大幅度降低空隙率及孔径,定将有效地提高混凝土的弹生模量及强度。     

石灰改性汉中膨胀土试验研究

试验以石灰作为外掺料,对汉中中、强两种膨胀土进行了以界限含水量、自由膨胀率和强度等为指标的改性对比试验。试验表明：在不同掺灰剂量、不同龄期作用下,石灰对强膨胀土界限含水量的改性效果相对明显,其改性效果存在一个限值。掺灰量在6%左右时,两种膨胀土改良效果较好。在严格按照施工规范和控制技术标准进行现场掺料时,可适当缩短闷料时间。