A kind of phosphogypsum concrete filled steel pipe and its preparation method

Abstract

The invention relates to a phosphogypsum steel pipe concrete and a preparation method thereof. The phosphogypsum concrete filled steel pipe comprises the following components in parts by weight: 420-500 parts of phosphogypsum cement, 100-200 parts of pottery sand, 480-550 parts of river sand, 500-700 parts of phosphogypsum coarse aggregate, and water reducer 2.1‑3.5 parts, 140‑170 parts of water. Phosphogypsum concrete is filled in steel pipes, turning the disadvantages of phosphogypsum concrete into advantages. The micro-expansion of concrete comes from the hydration reaction of phosphogypsum cement itself, and there is no need to add expansion agent; the setting time of phosphogypsum cement is longer than that of ordinary Portland cement, and the setting time of the prepared concrete matches the pumping construction technology of steel pipe concrete; As an outer wrapping layer of concrete, it can protect phosphogypsum concrete from CO 2 The erosion of the phosphogypsum concrete filled steel pipe ensures the overall anti-carbonation performance.

Description

technical field [0001] The invention relates to the technical field of concrete materials, in particular to a method for preparing steel pipe concrete by using phosphogypsum. Background technique [0002] Phosphogypsum is a by-product of phosphoric acid production by wet process in phosphoric acid chemical industry. About 5 tons of phosphogypsum are produced for every ton of phosphoric acid produced. The stockpiling of phosphogypsum not only occupies a large amount of land resources, but also faces relatively large environmental and safety risks. Therefore, the resource utilization of phosphogypsum is imperative. At present, as far as my country's phosphogypsum comprehensive utilization technology is concerned, it is mainly used to prepare building gypsum products, cement retarders, soil conditioners, mine fillings, etc., but these utilization methods generally have low product grades and added value, phosphogypsum mixed Small quantity, narrow use range and other problems. ...

AI Technical Summary

Problems solved by technology

However, in the preparation and construction process of steel pipe concrete, there are still the following problems: the gap between the steel pipe and the concrete cannot be "vacated", and the usual method is to add an expansion agent to the concrete

Usually, Portland cement is used for steel pipe concrete, which has large cement fineness, fast hydration speed, low concrete water gel ratio, and high self-shrinkage of concrete. In addition, the concrete is wrapped in steel pipes and is in a closed environment, so the expansion agent is required for hydration. It is difficult to get sufficient water supply, and the expansion effect of the expansion agent is difficult to effectively exert, so it is still difficult to solve the problem of "voiding" between the steel pipe wall and the concrete when the expansion agent is mixed.

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