Research On Key Fabricating Technology Of Reactive Powder Precast Concrete (RPC) Components

With the rapid development of China High-speed Rail technology, requirementsof concrete widely-used in building engineering increase higher and higher. Thecommon-used high-performance concrete can not meet the modern design concept,regulation and service life of the concrete. PRC concrete, as a new type of concrete,has been used in some medium-sized projects in the foreign countries, due to itsexcellent mechanical properties and durability. However, in China, it has not beenwidely used in engineering, because part of the key technology on the PRC concretewas controlled by some manufacturers who possess these foreign patents. Owing tothe high use cost and the unstable performance the domestic application of the RPCconcrete is still limited. In this work, according to the requirement of the unit in someengineering standards and the actual situations, the results of the formulationcustomization, precast maintenance and the equipment choose were investigated toprovide scientific basis and technological support for the application of the RPCconcrete in engineering.Based on the mechanism analyses of RPC concrete and the economic comparisonon raw materials, after a series of experiments and tests, the optimized schedule ofraw materials were determined and the formula design of the RPC concreteproduction were evolved, according to the technical specifications and requirementsof the RPC concrete. The main properties of the RPC concrete production developedin this work arrive at the leading level in China. Local raw materials were widely usedto reduce the construction cost to the greatest content.According to different places and equipments, a set of unique dry-heat curingmethod was figured out. In terms of the dry/wet heat of the RPC concrete curing, i.e.,the concrete component dry-cured after static stop, and then damp heat for the secondmaintenance after the static stop for the second time, the internal structure damage canbe weakened in the heating-up period and the defects in the process of cement waterhot dry conditions can be avoided. The internal pore structure can be improvedcompared with that of the RPC concrete without curing. Compared with the previousway of steam curing process, this maintenance system can low the internal structuredamage of the concrete in the curing of heating up period, and decrease the internaldefects in the cement water dry heating curing process conditions, the internal porestructure is also improved.