Ultra-high performance cement-based pi-shaped girder poured with ultra-high performance cement-based composite

Abstract

The invention relates to an ultra-high performance cement-based pi-shaped girder poured with an ultra-high performance cement-based composite. The pi-shaped girder meets the following conditions: H1 / B1 is equal to (0.2-1); T1 / H1 is equal to (0.01-0.3); T2 / B3 is equal to (0.1-0.5); B2 / B1 is equal to (0.2-0.8); B3 / B2 is equal to (0.1-0.5); T2 / H1 is equal to (0.02-0.2); R2 / R1 is equal to (0.3-0.8); R3 / R2 is equal to (0.1-0.5); B1 is larger than or equal to 1500 mm and is smaller than or equal to 5000 mm; H1 is larger than or equal to 500 mm and is smaller than or equal to 3000 mm; the span L is equal to (10-200 m). According to the ultra-high performance cement-based pi-shaped girder, the grain composition of multielement cementing materials and grain composition of aggregates are optimized, and a chemical additive is used, so that the compressive strength reaches 170 MPa or above under standard curing for 28 d under the precondition that the material has good fluidity; the ultra high strength cement-based composite and a high strength rib material are adopted, the construction is reasonable, and the design is optimized, so that the whole component has the characteristics that light weight and durability are achieved, the upper structure and the deck slab are integrated, and quick prefabrication and assembly can be achieved, while the bearing capacity is guaranteed; the ultra-high performance cement-based pi-shaped girder can be applicable to quick construction of small-sized and medium-sized bridges in the fields of highways and railways.

Description

technical field [0001] The invention relates to a lightweight, high-strength π-shaped beam body, more specifically, an ultra-high-performance cement-based π-shaped beam poured from ultra-high-performance cement-based composite materials. Background technique [0002] The beam structure of small and medium-sized bridges in the fields of highways and railways mostly adopts hollow slab girders, T-beams or box girders of reinforced concrete or prestressed reinforced concrete structures. The beam structure accounts for at least 80% of the total. Hollow slab girders are generally suitable for bridges with a span of 8-20m, while T-beams are suitable for single-hole spans of 30-40m, and the scope of application for box girders is relatively small. wide. Ordinary concrete has become the main structural material of beam structures (including hollow slab girders, T beams and box girders) due to its cheapness and availability, but its shortcomings are also very significant, such as: (1...

AI Technical Summary

Problems solved by technology

Ordinary concrete has become the main structural material of beam structures (including hollow slab girders, T beams and box girders) due to its cheapness and availability, but its shortcomings are also very significant, such as: (1) Low strength, resulting in large structure size, self-contained Significant, long construction period; (2) high brittleness, poor toughness, easy to crack, and become a way for erosive media to enter the interior of the concrete; (3) poor durability, reflected in large permeability coefficient, poor frost resistance, and no corrosion resistance, etc. ; (4) Poor fatigue resistance, prone to fatigue cracks under repeated loads

my country has started large-scale bridge construction since the reform and opening up. In the past 30 years, more than 500,000 bridges have been built. According to incomplete survey statistics, nearly 1 / 4 of them have various types of diseases, which involve beams. Occupying a relatively large proportion, including beam cracking, damage, salt corrosion, steel corrosion, deflection, prestress loss, joint leakage, etc., the maintenance and reinforcement costs in the later period are astonishing, and the maintenance and reinforcement costs of a single bridge can exceed the construction cost. Cost, for the severely damaged beam body needs to be replaced again, at this time, it is necessary to chisel off the bridge deck pavement and deck and use large equipment to remove the heavy beam body, the cost is staggering, from the perspective of the whole life cycle of the beam structure, The economy of reinforced concrete beams with relatively low construction costs is greatly reduced

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