Vertical vibration thermoforming method suitable for bituminous mixture test piece with maximum particle size of aggregate indicated larger than or equal to 26.5mm

Abstract

The invention discloses a VVTM suitable for a bituminous mixture test piece with maximum particle size of aggregate indicated larger than or equal to 26.5mm. The VVTM comprises mixing bituminous mixture, and weighing dosages needed by a test piece; taking out a testing die and a cushion block which are preheated well, and diving the mixture into approximately equal two parts, evenly putting the two parts into the testing die in a two-layer mode, flatting the surface of the mixture into a protruding and arc surface after each lay of the bituminous mixture is inserted; detecting the temperature of the bituminous mixture in the testing die, after the mixture reaches the needed compaction temperature, fixing the testing die and the cushion block on a vibrating compaction device, and vibrating and compacting the bituminous mixture in the testing die for more than 95s and less than 105s. After vibrating compaction is finished, measuring the height of the test piece, if the height of the test piece does not meet the standards requirement of height, the test piece is canceled, a dosage of the bituminous mixture needed by the test piece is adjusted according to the actual height, and manufacturing the test piece again until the height meets the requirement; and at last after the testing die which is provided with the testing piece is cooled to the room temperature, removing the test piece. The method is convenient to operate, good in simulation effect and reliable in result.

Description

technical field [0001] The invention belongs to the technical field of traffic civil engineering applications, and in particular relates to a vertical vibration molding method (VVTM) suitable for asphalt mixtures with a nominal maximum particle size ≥ 26.5 mm. The size of the cylindrical specimen prepared by this method is Φ150mm×h95.3mm, which is used for the physical and mechanical performance test of asphalt mixture in the laboratory. The method is easy to operate, and the test results of the performance of the specimen can objectively reflect the performance of the compacted asphalt mixture, and the reproducibility is good. Background technique [0002] Asphalt mixture with a nominal maximum particle size ≥ 26.5 mm (referred to as "large particle size asphalt mixture") specimens mainly includes Marshall compaction method, Hveem rubbing method, GTM or SGC rotary compaction method, and wheel rolling method. The molding equipment used by the Hveem method, GTM or SGC method...

AI Technical Summary

Problems solved by technology

The density of the molded test piece cannot reflect the density of the pavement after many years of opening to traffic, and it is easy to cause engineering waste or early rutting of the pavement;

[0012] (2) The large-scale Marshall compaction method is no longer suitable for the needs of modern transportation development

The compaction work of the current large-scale Marshall compaction method was proposed based on the traffic volume in the early 1980s, but the current traffic conditions on arterial highways have undergone significant changes, showing the characteristics of "large flow and heavy axle load". Obviously, Marshall The density of the test piece obtained by compaction can no longer be consistent with the final density of the pavement under the action of modern traffic load for many years;

[0013] (3) The correlation between large Marshall compaction specimens and pavement is poor

The large-scale Marshall compaction method cannot simulate on-site compaction well, and the physical and mechanical properties of the formed test piece do not coincide with the actual core sample, so it is difficult to effectively reveal the law between the material composition structure and performance, which affects the optimal design and performance of the material composition. Improvement of asphalt mixture performance

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