Experiment method for measuring maximum dry density of highroad base material

Abstract

The invention discloses an experimental method for measuring maximum dry density of a road base material, which comprises the following steps: filling a mixture into a test die, fixing the test die on a vibration gauge, and vibrating and compacting the test die for 100 to 120 seconds; calculating the dry density of the sample, repeating the experiment for five times to obtain five groups of blended water contents and dry densities of the sample, and drawing a relation curve of the water contents and the dry densities, wherein the horizontal coordinate is the blended water content, the longitudinal coordinate is the dry density, the dry density corresponding to a peak value of the curve is the maximum dry density and the corresponding water content is the optimal water content; and parameters of the vibration gauge are configured as follows: 30+/-2Hz of vibration frequency, 7.6+/-0.2kN of exciting force, 1.4+/-0.2mm of nominal amplitude, 3.0+/-0.4kN of working weight, 1.2+/-0.2kN of loading system, and 1.8+/-0.2kN of unloading system. The method has the advantages of simple and convenient operation, reliable result and good repeatability.

Description

technical field [0001] The invention is applied in the field of traffic civil engineering, and relates to a method for simulating the on-site rolling effect of the road base, which is easy to operate, reliable in result and good in reproducibility. The maximum dry density ρ of the road base material dmax and the optimum water content w o method of measurement. Background technique [0002] At present, the heavy compaction method in the "Test Regulations for Highway Engineering Inorganic Binder Stable Materials (JTJ057-94)" is widely used to determine the road base material ρ dmax and w o , its principle and test steps are as follows: [0003] (1) One day before the scheduled compaction test, take a representative sample to measure its air-dried moisture content, weigh at least 5 samples, and the air-dried mass of each sample is about 5.5kg. [0004] (2) 5 to 6 different water contents are scheduled, with a difference of 1% to 2% in turn, and at least two of them are grea...

AI Technical Summary

Problems solved by technology

[0010] (1) The heavy compaction method lags behind the actual production

First of all, the indoor compaction method compacts the material to be compacted by applying an impact load, while the on-site vibration compaction compacts the material through high-frequency vibration; secondly, the compaction work of the heavy compaction method is based on 8~ The 12-ton road roller was proposed, but the road base compaction generally uses 18-22 tons of frequency-adjustable amplitude-modulated vibratory rollers, and the compaction work of the heavy-duty compaction test does not match the current compaction equipment

[0011] (2) The water content test method is unscientific

[0012] (3) Poor simulation effect, poor test reproducibility and cumbersome operation: First, the heavy-duty compaction test is performed on the sample in three layers, which is inconsistent with the rolling of one layer (thickness 15-20cm) in the actual on-site construction process ;Secondly, layered material loading and layered compaction thickness, roughening treatment after compaction, and surface leveling treatment of the sample after compaction will affect the compaction effect due to different testers

Finally, the process of measuring the air-dried moisture content of the aggregate during the material preparation process, loading the sample into the compaction cylinder in three layers and compacting each layer 98 times, and drying for 8-12 hours to measure the moisture content is complicated and time-consuming.

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