The Mix Proportion Optimal Design Of High Strength And High Performance Concrete Based On Specific Strength

With the development of economic and material science, as the major material of construction and civil engineerin, concrete has become one of the most consumable artificial materials due to the irreplaceable advantages. In order to adapt to higher, span-larger, durabler, load-heavier, more demands of seismic resistance, disaster prevention and the capacity of adverse environmental condition in modern construction and civil engineering, the progress of concrete has been moving towards greener, higher strength and higher performance and more sustainable. At present, apart from four components of concrete including cement, water, sand and stone, it has been the most commonly used as technical approach to mix active mineral admixtures, superplasticizer and other admixtures into concrete for high strength and high performance concrete(HSHPC), where the past mix proportion design of concrete has not been worked as well. Therefore, the research on method of mix proportion design of high strength and high performance concrete has academic significance and widespread engineering application value.As confirming the mix proportion of HSHPC, not only the various demands on engineering but also the material itself, and the compatibility between them should be considered.The study in this paper is combined with the program of the research on the material to structure integrating multi-objective optimization design of steel reinforced concrete composite structure(No.50978218), which belongs to Chinese Nature Science Foundation. Based on material itself, combined experiments with theory analysis and integrated into optimal conceptions, the evaluation of compatibility between polycarboxylates high performance water-reducing agent and cement, the effection and mechanism analysis of aggregate size, aggregate gradation, fly ash and silica fume were studied, the mathematical model between them and concrete strength was established, and then one mix proportion optimal design of HSHPC based on specific strength was achieved finally. The main researches are as follows.1. The parameters or indicators as setting time and bleeding rate characterizing the compatibility between polycarboxylates high performance water-reducing agent and cement had been added. Meanwhile, with the membership function on Matlab, the fuzzy evaluation model for comprehensive evaluation on compatibility between cement and polycarboxylates high performance water-reducing admixture by breaking the limitation of control water-reducing agent.2. The effect of the qualities and properties of aggregate on concrete had been studied, mainly including its morphology, flat and elongated particle content, strength, maximum size, grading and volume content. One numerical method on the best combination of various continuous gradating aggregates had been established based on Bolomey equation. At the same time, the calculation on mean particle diameter of aggregate particles based on gradating had been set. Through experiments and theoretical studies, the functional relationship between volume of cement mortar and mean particle diameter of aggregates had been built, thus the quantitative adjustment on mix proportion design of concrete to meet different workability using it can be realized.3. Studing on influence of fly ash or silica fume on concrete properties by tests and had been mechanistical analysis, mathematical model of the equivalent water-binder ratio was proposed, activity index based on specific strength model of fly ash or(and) silica fume in the form of single or double mixing, mathematic models on the general change regularities with its dosage were established.4. Investigating and learning from various methods of mix proportion design of concrete, based on the effects of raw materials to concrete performance, one optimal design method based on specific strength had been established, suitable for mix proportion design of HSHPC.个...