Study On The Properties Of Plastic Concrete

Plastic concrete is a kind of new-type concrete material, which has very low elastic modulus and good characteristic of plastic deformation. Therefore not only it can guarantee enough mechanical strength, but also anti-permeability. In the hydroelectric project of water conservancy it used widely, and receives the concern day by day too.This paper carries out following research work, in view of the current situation that uses extensively to plastic concrete but the technological and basic research of theory is still not enough, and the practical use condition in accordance with different area change greater.First we explored the influence of the binding medium and set-modifying agent, made by the industrial by-product composed of fly ash, steel slag, phospogypsum, etc., on the plastic concrete, and made an optimization probe on feasibility. On this base we carried on the optimization research about the plastic concrete component materials and mix ratio design, and probed into the influence law with such key mix ratio parameters as different quality cement, different addition agent, sand percentage, etc. All of these have offered beneficial technology to consult the basis to the technology systematization and standardization of the plastic concrete. Through researching on the durability tests, for instance resistance of freezing, resistance of losing, resistance of permeability and so on, and relevant microstructure, we also have probed into the structure principle and technology characteristic of the plastic concrete, and carried on corresponding explanation about the mechanism of influence of different factors. The main achievement it sums up to be: Right amount fly ash and steel slag replacing cement as plastic concrete binding mediums can meet the index tequirement of strength, and improve the internal structure of concrete to make a good programs on its plastic deformation and resistance of permeability, and thus, we can realize abolishing the source requirement of goods and materials. But because of the advantage of itscomponents and structure, the result of the fly ash should be obviously superior to steel slag; Right amount phospogysum have a good improvement result to delayed slump loss: Owing to outstanding dispersing function, the effectiveness of reduce water strength of FDN-a high rang water reduce-superiors to normal cement; the technical properties of the plastic concrete, disposed by the cement produced in rotary kiln and ordinary cement of high grade, obviously superiors to the plastic concrete disposed by the cement produced in shaft kiln, of low grade and having large admixture dosage; Replacing bentonite plasticizing agent of a certain amount with right amount ordinary clay dose not have obvious bad function on the strength and slump maintaining of the plastic concrete, but because of the montmorillonite's reducing, the elastic modulus increases to some extent. From the microstructure of the plastic concrete, we knew the cement hydration product can form the intact framework, and the secondary hydration product, such as fly ash, the particle of bentonite and sand even to distribute among the space of the framework particle, and the ensemble architecture is even. But based on bentonite particle, we can regard it as the finite element of uneven composite. So there is much tiny space inside, and the stress meeting an emergency incrassates very fast loading, but the structure in the space close progressively mainly, aggregate receives less strength and the concrete deformation is well but not destroyed easily. The characteristic of bentonite particle expansion after absorbing water also can close knit concrete structure further and increases its anti-permeability.