Coarse aggregate void test equipment

Abstract

The invention provides coarse aggregate void test equipment comprising a stand part, a base part and a controller. In the stand part, a stand is provided with a magnet, a motor and a speed reducer, and is further provided with a hammer lifting chain, a guide rail and a drop hammer guide rod; a slide block is sleeved on the guide rail, one side of the slide block is connected with the hammer lifting chain and the other side fixes a force transmission rod; a hammer lifting tongue board is fixed above the slide block and controls a drop hammer to move upwards to the set height along the drop hammer guide rod; the drop hammer can make free fall, and the lower end of the drop hammer is provided with a detachable hammer head; in the base part, the stand is fixed on the base, a graduator is fixed in the base, a servomotor on the graduator extends out of the top of the base and corresponds to the position of the force transmission rod, the base is provided with a rolling disc controlled by the graduator, and the rolling disc is provided with a fixed base and a test bucket; the drop hammer guide rod and the drop hammer can swing around a vertical shaft of the guide rail till corresponding to the center of the test bucket under the control of the magnet; and the controller is used for controlling the starting and the stopping of a counter, the switching on and off of a motor and the swinging of the drop hammer.

Description

technical field [0001] The invention relates to a test device used in scientific research, design and construction in the field of road engineering, in particular to a test device for the void ratio (VCA) of coarse aggregate crushed stone ore. Background technique [0002] The mineral void ratio of coarse aggregate is an important index to evaluate the compactness of asphalt mixture skeleton. Gaining importance. As an index to evaluate the tightness of the skeleton, its test determination includes two important issues: (1) Without the interference of fine aggregates, the accumulation of coarse aggregates in any state forms a skeleton, but different skeleton arrangements , but the degree of compactness varies greatly. Therefore, it is more appropriate to use the aggregate void ratio in the accumulation state to evaluate the compactness of the coarse aggregate in the asphalt mixture; (2) How to measure the bulk density of the coarse aggregate. We first focus on the first que...

AI Technical Summary

Problems solved by technology

As an index to evaluate the tightness of the skeleton, its test determination includes two important issues: (1) Without the interference of fine aggregates, the accumulation of coarse aggregates in any state forms a skeleton, but different skeleton arrangements , but the degree of compactness varies greatly, so it is more appropriate to use the mineral material gap ratio under the accumulation state to evaluate the degree of compactness of the coarse aggregate in the asphalt mixture; (2) How to measure the bulk density of the coarse aggregate

We first focus on the first question, which state of bulk density can be used to evaluate the compactness of coarse aggregate in asphalt mixture more objectively and accurately? In the prior art, for the tamping of coarse aggregates, my country's "Highway Engineering Aggregate Test Regulations" stipulates that manual tamping and shaking table vibration methods are used. The main problems of these methods are: (1) the tamped test piece The surface needs to be filled manually, so the results are greatly influenced by human factors, resulting in low reproducibility and reproducibility of the results; (2) The tamping work cannot be quantified; (3) The VCA value obtained under the existing method and The formation state of the coarse aggregate void ratio in the asphalt mixture is quite different, the compaction work of the dry compaction method is significantly smaller than that of the asphalt mixture, and the void ratio of the formed coarse aggregate skeleton is too large, as the asphalt The evaluation standard of the compact state of the mixture skeleton is too loose, which loses the meaning of control

In addition, in order to avoid the above problems, some studies have adopted the direct application of Marshall compaction equipment for compaction of coarse aggregates. Although this method can meet the requirements of compaction work, the experimental results show that the crushing rate of aggregates is too large, and the actual The formed coarse aggregate mixture has deviated from the design gradation, and the measured coarse aggregate ore gap ratio is not representative

In view of the problems existing in the existing methods can no longer meet the requirements of today's asphalt mixture material design, it is necessary to develop a new type of coarse aggregate ore gap ratio test device, and make necessary improvements to the current test method

Images