A kind of C60 self-compacting shrinkage-resistant cracking-resistant concrete suitable for steel anchor beam and cable tower anchorage structure and its preparation method

Abstract

The invention discloses a C60 self-compacting, shrinkage-resistant, and crack-resistant concrete suitable for the anchorage structure of steel anchor beams and cable towers. The nitrile fiber, micron modified absorbent cotton cellulose, cement slurry microstructure regulator, water and super-dispersed water-reducing, shrink-reducing and plastic-preserving admixture are prepared as raw materials. Its initial slump ≥ 230mm, expansion ≥ 630mm, 28d compressive strength ≥ 70MPa, 28d splitting tensile strength ≥ 5.8MPa, toughness index I5 ≥ 3.0, 28d self-shrinkage rate < 0, 28d dry shrinkage rate < 0, The carbonization level reaches T‑IV, and the crack resistance level reaches L‑V. It has excellent mechanical properties, crack resistance and durability, and can solve the common problems of high cement and cementitious materials, large shrinkage and easy cracking in bridge tower concrete at this stage. problem, suitable for popularization and application.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a C60 self-compacting, shrinkage-compensating, crack-resistant concrete suitable for steel anchor beam and cable tower anchorage structures and a preparation method thereof. Background technique [0002] The anchorage area of ​​the super-high cable tower of the Hutong Yangtze River Bridge adopts the steel anchor beam + steel corbel structure, that is, the steel anchor beam is set on the steel corbel inside the cable tower, and the stay cables are anchored at both ends of the steel anchor beam. The concrete inner tower walls are connected by shear nails. Due to the existence of steel corbels, shear nails, and steel mesh inside the tower wall, it is difficult to pour the tower column. At the same time, the temperature and concrete shrinkage and creep have a great influence on the internal force of the bridge tower. In severe cases, the tower wall will crack. Therefore,...

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Problems solved by technology

[0003] However, the C60 concrete currently used for the anchorage structure of steel anchor beams and cable towers generally has the following problems: (1) the admixture used has limited dispersion ability to cement, and about 10% of the cement particles in the concrete have not been fully hydrated , just plays the role of inert filling. Therefore, the amount of cement and cementitious materials in bridge tower concrete is generally high, and the concrete has a large adiabatic temperature rise, large shrinkage, and easy cracking; (2) Add expansion agent to high-strength concrete to compensate Shrinkage, due to the low water-binder ratio of concrete, there is not enough water for the expansion agent to react in the later stage of hydration, and its expansion efficiency is difficult to exert, and the due shrinkage compensation effect cannot be achieved; (3) The anchorage structure of steel anchor beam and cable tower The stress characteristics and service environment require concrete to have good crack resistance and durability. At present, the commonly used anti-crack measure is fiber crack resistance. However, ordinary admixtures have limited effects on reducing the viscosity of concrete. Adding fibers to high-strength concrete will seriously affect the performance of concrete, making it difficult to achieve self-compacting and super-elevation pumping

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