外文翻譯--再生改性混凝土的性能-文庫(kù)吧
2025-04-17 07:52 本頁(yè)面
【正文】 construction waste especially recycling old concrete utilization. According to statistics, since the 9039。s, the annual consumption of the world total has more than 80 tones of concrete. In concrete aggregate accounted for over 70% of the total mass. 3 Compensating shrinkage of modified concrete Normal concrete is to use a wide range of building materials, but because of its limit extension rate is low, easy to crack in the dry shrinkage, creep, temperature effect, resulting in leakage caused by corrosion of reinforcement and concrete engineering, use function and the life of structures. The research indicated that, the swelling agent or expansion of shrinkage pensating concrete cement, concrete cracking is to solve the effective technical way infiltration problem because of shrinkage pensating concrete hardening process in water can produce ~ Map pre pressive stress (or stress), the stress can be offset or partially offset by concrete shrinkage, creep, temperature induced tensile stress, so as to improve crack resistance of concrete engineering。 in addition, due to the hydration expansion hole filling effect of products, the large hole in cement paste is smaller, the total porosity, which can improve the pore structure of concrete, greatly improve the impermeability of concrete, therefore make shrinkage pensating concrete expansive cement in foreign countries is also known as the waterproof cement. The shrinkage pensating concrete is an important branch of modern concrete science, its unique properties, is to solve the volume stability, high performance concrete is an important technical basis to improve the durability of concrete, the research on it has yet to be further and perfect, this paper expounds some basic properties of shrinkage pensating concrete. Expansion agent Physical and chemical properties: refers to the concrete expansion agent in concrete mixing process and the cement, water mixing after hydration reaction of stringier [3CaO ? Al2O3 ? 3CaSO4 ? 32H2O] or calcium hydroxide [Ca (OH) 2], make concrete produce volume expansion admixture. Concrete expansion agent is used to prepare the expansive concrete (including shrinkage pensating concrete and self stressing concrete), shrinkage pensating concrete shrinkage and pacting concrete with, improve concrete anti permeability role pensation concrete, in civil engineering in two aspects mainly used for waterproofing and anti cracking, now use more occasions is preparation of high grade waterproof concrete and appropriate to extend the expansion joint or post cast band spacing. 4 Basic properties of shrinkage pensating concrete Material Concrete before hardening Agent content and fresh initial concrete slump expansion: expansion agent effect on the initial slump of fresh concrete degree, largely depends on the expansion agent fineness, when the expansion and cement fineness difference, mixing water demand is basically the same, almost has no effect on the initial slump. Setting time Effect of expansive agent on setting time of concrete expansion admixture added: no matter what, will make the concrete set
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