Proportionate And Construction Technics Of High-capability Concrete

High-capability concrete is a new type concrete, which is manufactured by adopting modern concrete treating techniques based on extensively enhancing common concrete's capability. This new type concrete's durability is the main design target, while for different purpose, the following capabilities will be guaranteed: durability, applicability, intensity, size stability and economy. Therefore, the proportionate characteristics of high-capability concrete are low water-mucus ratio, high grade raw materials, adequate fine mineral adulterant and high-efficient addictive.After application of this high-capability in the past 20 years, there are still some shortages in its proportionate and construction technics:1.Designing methods for proportionateBecause of the complex raw materials used in high-capability concrete and required high techniques, there is no uniform computing methods. The design methods used by each country are all experience and examination methods according to respective practice, but all these methods observe three principles: water-ash ratio, maximum compaction, minimum unit water consumption.2. The performance testing method for high-capability concrete is immatureBy present, many new testing methods have been brought forward to resolve this problem, in common use such as: L-type flowing test, O-type (V-type) funnel test, filling test, reinforced steel bar pass-through test, mortar current and change test, etc. But according to the reflection, all the above methods are imperfect and needing improvement.For high-capability concrete's shortcomings in design and construction technics and, based on the background of high-capability concrete's use in prefabricated double-line box-girder railway engineering, this thesis exerts experimentation methods including raw material examination, concrete proportionate design, performance test and durability test for the systematic investigation, as provide practicable parameter for proportionate and site construction technics of high-capability concrete.Within this thesis, the main studies are:1. Quality requirements for raw materials used in high-capability concrete;2. Proportionate design methods for high-capability concrete;3. Main factors affecting proportionate design methods for high-capability concrete;4. Key construction technics for high-capability concrete's application in prefabricated box girderFor the pumped high-capability concrete are complex in components and abundance in construction and curing requirements and, combined with 32m prefabricated double-line box girder for railway engineering, this paper summarizes the high-capability concrete construction methods for prefabricated 32m double-line box girder in railway engineering.The investigation indicates:1. Raw materials'indexes greatly influence the capability of this new type concrete.2. The main factors that affect the proportionate design for the high-capability concrete include: environmental factors, quality class of provided raw materials, dimensions of site structures, site construction conditions and curing plans for high-capability concrete.To sum up, through chamber experimentation and research to site construction and past investigation, we make comprehensive cognition of the high-capability concrete's proportionate design and construction technics. We believe that this thesis will make technological support for high-capability concrete's proportionate design and construction technics.