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

研究了养护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，标准水养护时的搅拌水和渗透水都不足以完成整个试件的水化。因此，研究养护条件以改善水化过程中试样在离表面任意距离处的性能。当W/C较低时，掺有ae -外加剂的水（表面张力较低）和高压水固化的试件，其水化程度和强度的提高程度均高于标准水固化。在水化过程中向试样提供额外水的固化对胶结材料的性能有很大的影响。对于渗透养护的影响，本研究得出以下结论：1)对于低W/C （W/C = 0.20、0.2、0.30）的硬化水泥浆体，掺水水无法填充水化反应形成的孔隙，也无法渗透到硬化水泥浆体的中心部位。试件中部自干较大，水化进程变慢。2)在低水化比的试样表面到中部的任意距离上，均表现出不同程度的水化和由于缺乏水化而引起的自干。中心部位的强度低于近表面部位的强度。3)经标准水养护处理的低W/C高强混凝土，其本体与表层水化自干程度存在明显差异。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。水对试样的渗透程度和自干程度因水的固化而不同。需要进一步研究寻找合适的养护条件作为高强混凝土的标准。然而，本文发现高压水养护和低表面张力水养护能够使试件的强度发展高于标准养护，特别是在低W/C比下。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