Simple method for rapidly testing restrained expansion rate of calcium sulphoaluminate expanding agent

Abstract

The invention discloses a simple method for rapidly testing a restrained expansion rate of a calcium sulphoaluminate expanding agent. The simple method comprises the steps of: sampling a concrete mixing material which is doped with an expanding agent and applied on the scene to form cement expanding agent mortar; filling the cement expanding agent mortar into three beer bottles with the same volume of 600 ml respectively by adopting a hopper after broken stones in the cement expanding agent mortar are screened away through a screen of phi 5 mm, wherein the filling amount of each beer bottle is 700 g; putting each beer bottle on a desk surface on which a towel is cushioned for vibration after the cement expanding agent mortar in each beer bottle is tamped lightly by a bamboo sheet; stopping vibrating after the surface of the cement expanding agent mortar layer in each beer bottle is observed to be basically flattened and the mortar is output; placing each beer bottle in a room to be maintained for 24 hours; adding 200 ml water in each bottle; starting timing; checking every four hours; observing expanding and cracking time of each beer bottle; proving that the restrained expansion rate of the used expanding agent can reach to the demand of not less than 0.025% in water for seven days of the national standard and the expanding agent is a qualified expanding agent product if at least two beer bottles within 140 hours are cracked; otherwise, proving that the expanding agent is an unqualified expanding agent product.

Description

technical field [0001] The invention relates to a simple and easy method for quickly testing the limited expansion rate of calcium sulfoaluminate expansion agents. Background technique [0002] Concrete expansion agent has a wide range of uses in waterproofing projects and projects that need to compensate for concrete shrinkage. At present, my country's concrete expansion agents are divided into three types according to the prepared hydrate materials: calcium sulfoaluminate expansion agents, calcium oxide expansion agents and calcium sulfoaluminate + calcium oxide expansion agents. The limited expansion rate of concrete expansion agent is the main quality index of the expansion agent. The national standard GB23439-2009 for type I expansion agent requires that the expansion rate be limited to ≥0.025% after 7 days of immersion in water. According to the requirements of the national standard: testing the expansion rate of the expansion agent must be tested by professional and...

AI Technical Summary

Problems solved by technology

At present, although the expansive agents supplied on the market also hold the expansive agent inspection report, their expansive performance and quality vary greatly, and due to the different properties of cement used in concrete engineering in various regions, the mud content of yellow sand and stones with a coarse and fine particle size Different, the chemical composition is different, and the strength requirements of each project for concrete are also different. Whether the expansive agent used to limit the expansion rate meets the requirements of the national standard can not be determined in a short period of time by using the above-mentioned rapid test method.

As for the unqualified expansion agent, although it has a certain expansion performance, when the cement slurry is put into the beer bottle, some will not crack at all, and although some can crack, they will not reach the level after 7 days of immersion in water. National standard requirements (see Table 3)

Therefore, the above-mentioned rapid test method cannot meet the needs of large-scale and wide-ranging calcium sulfoaluminate expansion agents using units, and the limited expansion rate test of calcium sulfoaluminate expansion agents.

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