The Systematization of the Elemental Technology of Materials for the Control of Concrete Fluidity

为了发展自密实混凝土、高强混凝土和高耐久性混凝土，必须用梳形高效减水剂控制混凝土的流动性。本文系统地论述了控制混凝土流动性的材料基本技术：控制流动性必须控制铝酸盐相的早期水化;在C_3A周围形成的凝胶中含有大量的SO_4 ~（2-），阻碍了C_3A的早期水化<2->。在C_3A-硫酸钙体系中加入梳形高效减水剂，抑制了SO_4 ~（2-）向凝胶的供应，加速了C_3A的早期水化<2->。在C_3A-石膏体系中，游离CaO含量的增加延缓了C_3A的早期水化。结果表明，增加CaO含量可有效控制梳形高效减水剂水泥的早期水化。无机电解质对梳型减水剂悬浮液流动性的影响表明，接枝长度越短的聚合物越容易被吸附，尽管吸附位点的数量减少。用苯乙烯或烯丙基磺酸酯取代甲氧基聚乙烯，随着共聚物组成的变化，接枝链间距延长。掺缓冷高炉矿渣微粉（SBFS）的砂浆流动度保留率小于未掺SBFS的砂浆流动度保留率，这是由于缓冷高炉矿渣微粉延缓了C_3A的早期水化。此外，还研究了粉煤灰中的未燃碳、骨料中的粘土矿物以及外加剂对梳型高效减水剂悬浮液流动性的影响。

For the development of self compacting concrete, high strength concrete and high durable concrete, it is necessary to control the fluidity of concrete with comb-type superplasticizers. This study discusses the systematization of the following elemental technologies of materials for the control of concrete fluidity.It is necessary to control the early hydration of aluminate phase in order to control the fluidity. The early hydration of C_3A is retarded, as there is much content of SO_4^<2-> in the gel formed around C_3A. Adding of comb-type superplasticizers in C_3A-calcium sulfates systems accelerates the early hydration of C_3A, because the supply of SO_4^<2-> to gel is inhibited. Increasing free-CaO contents retards the early hydration of C_3A in C_3A-gypsum system. It is proposed that the increase of CaO contents would be effective for controlling the early hydration of cement with comb-type superplasticizers. For the influence of inorganic electrolytes on the fluidity of suspension with comb-type superplasticizers, the polymer having a shorter grafted length is adsorbed more easily even though the number of adsorption sites is decreased. The interval between grafted chains were prolonged, with changing composition of copolymer when methoxypolyethylene is replaced by styrene or allyl sulfonates. By adding of slowly cooled blast furnace slag powder (SBFS), the fluidity retention of mortar is smaller than that of mortar without SBFS due to the retardation of the early hydration of C_3A. In addition, the influence of unburned carbon in fly ash and clay mineral of aggregates or additives on the fluidity of suspension with comb-type superplasticizers have been also investigated.