Lightweight aggregate concrete suitable for high remote pumping

Abstract

The invention relates to a lightweight aggregate concrete suitable for high remote pumping. The lightweight aggregate concrete is characterized by comprising the following components in percentage by weight: 30%-40% of cement paste, 25%-35% of light crude aggregate materials and 30%-40% of refined aggregate materials, wherein the density of the cement paste is not larger than 2000kg / m<3>, the apparent density of the light crude aggregate materials is not smaller than 1000kg / m<3> and the difference between the density of the cement paste and the apparent density of the light crude aggregate materials is smaller than 600kg / m<3>. According to the invention, the cement paste has a viscosity of not smaller than 10mPa.S and is obtained by uniformly mixing the following materials in percentage by weight: 40%-60% of cement, 10%-20% of fly ash, 0%-20% of lightweight powder, 3%-5% of wollastonite, 20%-32% of water, 1%-4% of an inorganic viscosity modifier, 0%-0.2% of cellulose ether and 0.5%-1.4% of a polycarboxylic acid high-performance water reducer. The lightweight aggregate concrete has good workability, uniformity and pumpability, and can be used for high remote pumping.

Description

technical field [0001] The invention belongs to the technical field of concrete, and in particular relates to light aggregate concrete suitable for high-level pumping. technical background [0002] Lightweight aggregate concrete, also known as lightweight aggregate concrete, is formulated with light coarse aggregate, fine aggregate, cement, water, and chemical admixtures and mineral admixtures if necessary, with a dry apparent density of less than 1950kg / m 3 of concrete. Light aggregate concrete has high specific strength, which can reduce the self-weight of the building, reduce the cost of foundation treatment, reduce the structural section and increase the use area, which can reduce the construction cost by 5% to 10%. It also has good durability, fire resistance, and earthquake resistance. Therefore, lightweight aggregates have broad application prospects in building structures, especially in long-span, high-rise and super high-rise buildings. [0003] In the constructio...

AI Technical Summary

Problems solved by technology

[0004] However, there are several main problems in lightweight aggregate concrete: ① The aggregate is easy to float, causing the components in the concrete to be stratified and the homogeneity is poor; ② The workability and pumpability are lost too quickly during the pumping process; Bleeding and segregation are prone to occur when pumping is suspended due to replacement and other reasons

However, the limitation of this method is that the particle size of the selected light and coarse aggregate is too small, and the water absorption rate of the light aggregate is too high under the high pump pressure during the elevation pumping process, which will cause the workability of the light aggregate concrete to deteriorate. Lost too fast over time

In addition, the simple use of two organic tackifiers, cellulose ether and polyethylene oxide, in this method has a limited effect on increasing the viscosity of the slurry. Although increasing the amount of these two organic tackifiers can further increase the viscosity of the slurry, it will reduce the viscosity of the slurry. Significantly reduce the strength of lightweight aggregate concrete; similarly, the effect of simply increasing the amount of fly ash to reduce the density of the slurry is also very limited

[0007] Chinese patent 201310742631.6 proposes a self-compacting lightweight aggregate concrete and its preparation method. This method uses ceramic sand to prepare all-light concrete, and reduces the density of the slurry by adding floating beads to the slurry components, further reducing the light aggregate. However, the ceramic sand used in this method has a very small particle size and a high water absorption rate. In this method, it is not proposed that the workability and workability of light aggregate concrete due to the water absorption of light aggregate under pump pressure Solutions for Decreased Pumpability

Chinese patent 200910177544.4 proposes a lightweight aggregate concrete containing zeolite powder and natural river sand and its preparation method. In this method, zeolite powder is introduced as a tackifier to improve the cohesion and water retention of lightweight aggregate concrete, but The 500-grade shale ceramsite with a particle size of 5-25 mm selected by this method has a large particle size, a low apparent density, and a large difference in density from the slurry, and there is still a large component stratification during the elevation pumping process. risks of

In summary, the light aggregate concrete in these existing technical solutions has certain limitations when applied to elevation pumping construction

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