Nano silicon dioxide and basalt fiber synergistically enhanced recycled concrete and preparation method thereof

Abstract

The invention discloses a nano silicon dioxide and basalt fiber synergistically enhanced recycled concrete and a preparation method thereof.The mass ratio of cement to water to modified recycled coarse aggregate to natural fine aggregate to basalt fiber to polycarboxylic acid high-performance water reducing agent in the recycled concrete is 1: (0.48-0.52): (2.72-2.76): (1.45-1.49): (0.006-0.018): (0.006-0.012), the compressive strength of the recycled concrete reaches 36.51 MPa, the splitting tensile strength reaches 2.98 MPa, and the tensile strength of the recycled concrete reaches 36.51 MPa. And the breaking strength reaches 5.27 Mpa. Besides, nano silicon dioxide which is not completely reacted and exists on the surface of the recycled coarse aggregate can react with a cement hydration product Ca (OH) 2 to generate C-S-H gel, so that mortar attached to the surface of the recycled coarse aggregate is strengthened, and the strength of an interface transition area of the recycled concrete is improved; the distribution of the basalt fibers is facilitated by the rough surfaces of the nano silicon dioxide and the recycled aggregate, so that the toughening and anti-cracking effects of the fibers are fully exerted, and the mechanical property and the durability of the recycled concrete are remarkably improved by the synergistic effect of the nano silicon dioxide and the basalt fibers.

Description

technical field [0001] The invention relates to the field of recycled concrete, in particular to a recycled concrete that is synergistically reinforced by nano-silica and basalt fibers and a preparation method thereof. Background technique [0002] In recent decades, the construction industry has developed rapidly, and a large number of existing concrete structures have been transformed or demolished, resulting in a large amount of waste concrete. According to incomplete statistics, the global use of concrete exceeds 4 billion cubic meters per year, and the use of sand and gravel materials exceeds 8 billion tons per year. In addition, the concrete industry's share of greenhouse gas emissions is about 10% of its global total, nearly half of which can be directly or indirectly related to the production of cement. According to the statistics of the analysis report, on average, nearly 600 tons of construction waste will be generated for every 10,000 square meters of new buildin...

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Problems solved by technology

[0006] In order to improve the defects of recycled concrete such as high brittleness, low tensile strength, easy shrinkage, and cracking, the research shows that the incorporation of fibers can effectively improve the crack resistance of concrete, enhance the ductility of concrete, and reduce the appearance of cracks, thereby improving the mechanics and durability of concrete. performance

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