Design method for mixing proportion of self-compacting concrete mixture

Abstract

The present invention belongs to the technical field of concrete construction and particularly relates to a design method for a mixing proportion of a self-compacting concrete mixture. The method comprises the steps of: determining a performance design target; determining mixing strength and a water-binder ratio; determining densest gradation (or a sand rate) of aggregates and void ratios of different packing states; determining the usage amount of binding materials and mixing water; determining the usage amount of the aggregates; determining the usage amount of additives; determining the actual adding amount of the mixing water; and the like. According to the method provided by the present invention, aimed at blindness of material selection during self-compacting concrete mixing proportion design in the prior art, based on a fundamental theory of particulate dense packing and a composition rule of reaching a densest packing state of solid particulate materials with different particulate diameters, a mixing proportion of different materials is determined by an actually measured densest packing state, and relationships are established between the material mixing proportions corresponding to different densest packing states and expected self-compacting performance grades of the mixture, so that the design method used for the mixing proportion of the self-compacting high-performance concrete mixture and based on a use performance as a target is constructed.

Description

technical field [0001] The invention belongs to the technical field of concrete construction and relates to a method for designing the mixing ratio of self-compacting concrete mixture. Background technique [0002] Self-compacting concrete is a new type of high-performance concrete that has high fluidity at low water-binder ratio without segregation and bleeding, and ensures that it can fill the mold cavity and wrap steel bars by itself without vibration under unfavorable pouring conditions. Due to the use of a large amount of industrial waste mineral fine admixtures, self-compacting concrete can significantly reduce the temperature rise of concrete, thereby improving the ability to resist external environmental erosion and deterioration, thereby improving the durability of the concrete structure; at the same time, the use of mineral fine admixtures saves cement, Reduced carbon emissions and energy consumption in cement production. Due to the above advantages, self-compacti...

AI Technical Summary

Problems solved by technology

Although the packing theory has been studied and applied in the concrete industry for many years, so far, there is no set of practical methods for determining the mix ratio of self-compacting high-performance concrete based on this theory, let alone the material of the mix. The composition is directly related to the self-compacting performance level. For example, the Chinese patent (application publication number CN103304206A) discloses a super-high-strength self-compacting concrete and its preparation method. Composed of cement, water and PVA fiber, the mass percentages of cement, slag and silica fume that make up the cementitious material are: cement 70%-80%, slag 10%-20%, silica fume 5%-10%

Although the invention mentions the optimal design of ultra-high-strength self-compacting concrete based on the closest packing theory, the application documents do not involve information on any method for determining the amount of various materials using the closest packing theory. It is still the traditional concrete mix design method and mode, and the performance of the designed mixture is unpredictable, and it must be tested and adjusted in the later stage

[0005] Generally speaking, the blindness of the existing technology in the design of material mix ratio not only increases the workload of trial adjustment, but also brings waste of resources. Therefore, it is necessary to explore a more practical self-compacting high-performance concrete A New Method of Designing Mixture Ratio

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