A STUDY ON NEW MIXING METHOD AIMED AT MAKING TO QUALITY OF HIGH STRENGTH LOW WATER-CEMENT RATIO CONCRETE

研究了固化水渗透条件对胶凝材料性能的影响。在低水灰比(W/C)的大尺寸试件中，标准水养条件下的混合水和渗透水都不足以完成整个试件的水化。因此，在水化过程中，研究了固化条件以提高样品在任何距离表面的性能。当水化比较低时，用表面张力较低的AE-外加剂水和高压水养护的试件，其水化程度和强度的提高比标准水凝处理的更好。水化过程中向试件补水的处理对胶凝材料的性能影响较大。1)对于W/C较低的水泥浆体，如W/C为0.20，0.2…超过5和0.30，发现混合水不能填充水化反应形成的气孔，不能渗透到硬化水泥浆体的中心部分。2)在低水碳比的试件中，从表面到中部的任意距离都表现出不同程度的水化和由于缺乏水化而导致的自脱水现象。3)经标准水养护处理的低水/碳比高强混凝土在体层和表层的水化和自干化程度明显不同。因此，由于表面张力的差异，不适合采用与普通混凝土相同的养护条件。不同的养护水对试件的渗透程度和自干燥程度不同。还需要进一步的研究，以找到适合高强混凝土标准的养护条件。然而，本文发现，高压水养护和低表面张力水养护比标准养护能够更多地提高试件的强度，特别是在低水胶比时。较少

Influences of penetrative condition of curing water on properties of cementitious materials were investigated. In a large-size specimen with a low water-cement ratio (W/C), both the mixing water and penetrative water at standard water curing are not sufficient to complete the hydration of the entire specimen. Therefore, curing conditions were studied to improve the properties of the specimens at any distances from the surface during hydration process. When W/C is low, specimens cured with water containing AE-admixture, which has low surface tension, and water under high pressure was able to improve the degree of hydration and strength more than those subjected to the standard water curing.Curing of supplying additional water to a specimen during hydration has large influences on properties of cementations materials. The following conclusions regarding to influences of penetrative curing were obtained in this study :1) For the hardened cement pastes with low W/C, such as W/C of 0.20,0.2 … More 5 and 0.30, it was found that the mixing water was unable to fill pores formed as a result of hydration reaction, and to penetrate into the central part of hardened cement pastes. A larger self-desiccation occurs in the middle part of specimens and the progress of hydration became slower.2) At any distance from surface to middle part of the specimen with a low W/C, different degree of hydration and self desiccation due to the lack of hydration were shown. Additionally, the strength in the central part of specimens was lower than in the near-surface-area specimens.3) The high-strength concrete with low W/C that treated by the standard water curing clearly showed difference in degree of hydration and self-desiccation in the bulk and in the surface layer. Consequently, it is not suitable to apply the same curing condition as applied to the normal concrete because of the difference in surface tension. The degree of the penetration of water into the specimen and degree of self-desiccation were different by the curing water. Further investigations to find the appropriate curing condition as standard for the high-strength concrete, are needed. Nevertheless in this paper, it was found that high pressure water curing and low surface tension water curing was able to develop strength of specimens more than that with the standard curing, especially at a low W/C ratio. Less