Mix proportion design and optimization method of machine-made sand self-compacting concrete

Abstract

The invention relates to a mix proportion design and optimization method of machine-made sand self-compacting concrete. The method comprises the following steps: 1) determining the mass of coarse aggregate, the apparent density of the coarse aggregate and the bulk density of the coarse aggregate in a powder material, machine-made sand grains and unit volume concrete; 2) obtaining the use mount ofthe coarse aggregate and the volume of mortar according to performance requirements and the extra coefficient of the mortar; 3) determining a water-binder ratio according to design strength; 4) assuming the volume ratio of a net paste volume to the machine-made sand grains and calculating the mass of cement, the mass of the machine-made sand grains and the mass of mixing water; 5) adjusting the use amount of an additive in the machine-made sand self-compacting concrete according to the workability of the concrete; 6) optimizing a mix proportion meeting requirements on concrete performance according to an excellent-inferior coefficient. Compared with the prior art, the mix proportion design and optimization method has the advantages of simple steps, small calculation amount, wide application, workability and strength and the like.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a mixing ratio design and optimization method of machine-made sand self-compacting concrete. Background technique [0002] Concrete is the most widely used and used building material in the world today. Since the self-compacting concrete mixture has high fluidity and does not segregate or bleed during the concrete pouring process, it can be used without vibration. Completely relying on its own gravity to achieve dense filling, it has been widely used in a large number of infrastructure and civil construction in our country. With the shortage of river sand resources and the gradual improvement of the awareness of the sustainable development of concrete, the gradual replacement of river sand by machine-made sand has become the trend of sustainable development of concrete. [0003] Machine-made sand self-compacting concrete can be regarded as a composite material that fi...

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Problems solved by technology

Due to the failure to consider the influence of the characteristics of machine-made sand, it is difficult to prepare through the "Ordinary Concrete Mix Proportion Design Regulations" JGJ 55, "Self-Compacting Concrete Application Technical Regulations" JGJ / T 283 and "Self-Compact Concrete Mix Proportion Design and Construction Guidelines" CCES 02 Machine-made sand self-compacting concrete that satisfies workability, strength and durability

In actual engineering, the mix ratio design of machine-made sand self-compacting concrete is mainly based on experience, and the required mix ratio often needs a lot of experimental work to obtain, which is time-consuming and labor-intensive, and the obtained mix ratio often shows poor workability and mechanical properties. Inconsistency, unable to optimize the mix ratio on the basis of comprehensive workability and strength through quantitative methods

[0004] Chinese patent CN 105801031 A discloses a method for designing the mix ratio of artificial aggregate concrete. It proposes to design the mix ratio of concrete through the composition ratio relationship between powders, which mainly focuses on the design of powders, without considering powders, machine-made sand, Coarse Aggregate Relationship

Chinese patent CN 105974791 A discloses a concrete mix ratio optimization system control method, which obtains the relationship between concrete performance and raw materials through the setting and calculation of multi-layer weight values. Machine-made sand concrete, the introduction of stone powder increases the number of parameters, making it more difficult to adopt

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