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

控制混凝土流动性的材料基础技术的系统化

基本信息

批准号：
13650502
负责人：
SAKAI Etsuo
金额：
$ 2.18万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

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.

为了发展自密实混凝土、高强混凝土和高耐久性混凝土，需要用梳型高效减水剂控制混凝土的流动性。本研究对控制混凝土流动性的材料的以下基本技术进行了系统化探讨。为了控制流动性，必须控制铝酸盐相的早期水化。由于C_3A周围形成的凝胶中存在大量SO_4^<2->，C_3A的早期水化被延迟。在C_3A-硫酸钙体系中添加梳型高效减水剂，抑制了SO_4^<2->向凝胶的供给，加速了C_3A的早期水化。增加游离CaO含量可延缓C_3A-石膏体系中C_3A的早期水化。提出增加CaO含量可有效控制梳型高效减水剂水泥的早期水化。由于无机电解质对梳型高效减水剂悬浮液流动性的影响，尽管吸附位点数量减少，但接枝长度较短的聚合物更容易被吸附。当甲氧基聚乙烯被苯乙烯或烯丙基磺酸盐取代时，接枝链之间的间隔延长，并改变了共聚物的组成。添加缓冷高炉矿渣粉(SBFS)后，由于C_3A早期水化的延迟，砂浆的流动性保持率比未添加SBFS的砂浆小。此外，还研究了骨料或添加剂中的粉煤灰和粘土矿物中未燃烧的碳对梳型高效减水剂悬浮液流动性的影响。