【摘要】 本文回顾了膨胀和自应力水泥发展以及对水泥石的硫铝酸盐膨胀研究的历史。介绍了建材研究院水泥所物化室自六十年代初至最近关于水泥石硫铝酸盐膨胀的研究结果。认为:1.在水泥石硬化初期形成的钙矾石起强度骨架作用,在水泥石具有一定强度后,继续形成的钙矾石才起膨胀作用;不管形成钙矾石的Al₂O₃、CaO、SO₃的来源如何,不管液相中 CaO的浓度是饱和还是不饱和,所形成的钙矾石均能引起膨胀。2.水泥石的硫铝酸盐膨胀时产生的自应力值和水泥石结构与下述条件有关:钙矾石形态（取决于液相CaO浓度）、数量、形成钙矾石时的水泥石强度;与钙矾石同时生成的胶凝相的形成方式、数量、形态以及混凝土的限制条件。3.水泥石液相中CaO低于饱和浓度时,某些铝酸盐矿物形成了膨胀性较小的钙矾石并在同一反应中形成了水化氧化铝凝胶,得到的水泥石的显微结构致密,强度和膨胀协调发展,混凝土的自由膨胀率和限制膨胀率的比值较小,有利于获得高自应力值及高气密性的自应力水泥混凝土。用上述论点,讨论了与形成钙矾石有关的膨胀现象和理论,展望化学予应力逐步赶上机械予应力及大幅度提高水泥制品抗气渗性能的前景。更多还原

【Abstract】 The history of the development of expansive and self-stressing cement and the inves-tigation of sulfoaluminate expansion of cement-stone were reviewed. Conclusions on thestudy of sulfoaluminate expansion of cement-stone made by the Physico-chemical Depart-ment of the Cement Research Division from the beginning of sixties were presented.They are: 1. Ettringite formed at the early hardening stage of cement paste cause the de-velopment of skeleton of strength, whereas those formed after cement-stone acquiring a de-finite strength will then produce expansion, irrespective of the source of Al₂O₃, CaO, SO₃or whether CaO concentration in the liguid phase is saturated or not.2. The self-stressingvalue resulted from sulfoaluminate expansion and the structure of the cement-stone isrelated to the following conditions: the shape of ettringite（depending on the CaO concen-tration in liquid phase）, their guantity, the strength of the cement-stone when forminginto ettringite; the mode of formation, the quantity and form of gel phase produced atthe same time as with the ettringite and the restraint condition of concrete. 3. At theundersaturated concentration of CaO in liquid phase of the cement-stone, ettringite withthe characteristic of lower expansion is formed from some aluminates, and hydroaluminagel is produced under the same reaction. These result in the micro-structure of cement-stonedenser, the development of strength and expansion more consistant and the ratio offree expansion and its restraint expansion lower. All of these are beneficial to provide highself-stressing value and low gas-permeability of self-stressing cement concrete. Basedon the above points of view, the phenomena and mechanism of expansion related to theformation of ettringite are discussed. The prospects that the value of chemical prestresswill get close by degrees to the value of mechanical prestress, and the low gas-perme-ability cement products could be made are expected.更多还原