Method for determining road roller compacted concrete composition based on pressing vibration method

Abstract

The invention discloses a method for determining a road roller compacted concrete composition based on a pressing vibration method. The method comprises the following steps of: placing samples into a volume tube in two layers, placing on-load press cakes on the surfaces of the samples, starting a vibrating table, measuring the head room of the volume tube, respectively determining the height of a first layer and the height of a second layer, leveling the surfaces of the samples, removing the samples and the volume tube together from the vibrating table, weighing the mass of the volume tube and the samples, taking out the samples, determining the volume of the roller compacted concrete sample, removing the sample, weighing, determining the water content, calculating the dry density, and with the dry density of the sample as the vertical coordinate and the water content of the sample as the horizontal coordinate, selecting the composition with large compactness and thickness satisfying the requirements as the compacted concrete composition according to test. The method disclosed by the invention ensures that the road roller compacted concrete composition has large compactness, meanwhile, the thickness of the road roller compacted concrete also can meet the construction requirements, and the method is simple and feasible to operate.

Description

technical field [0001] The invention relates to the technical field of concrete application, in particular to a method for determining the mixing ratio of road-use roller compacted concrete based on a pressure vibration method. Background technique [0002] The roller compacted concrete pavement structure has the advantages of low cost and good performance, and has been gradually applied to rural road construction. However, since RCC is an ultra-dry hard concrete with almost zero slump, its strength mainly depends on the interlocking effect of aggregates, so the design method of ordinary concrete mix ratio based on water-cement ratio is not suitable for RCC . In foreign countries, the design of the mix ratio of RCC for roads often adopts a compaction method similar to that of soil, that is, for a certain amount of dry concrete, increase or decrease the water consumption, and use the falling hammer compaction method to obtain the mixture with different water contents. Dry d...

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Problems solved by technology

However, since RCC is an ultra-dry hard concrete with almost zero slump, its strength mainly depends on the interlocking effect of aggregates, so the design method of ordinary concrete mix ratio based on water-cement ratio is not suitable for RCC

In foreign countries, the design of the mix ratio of RCC for roads often adopts a compaction method similar to that of soil, that is, for a certain amount of dry concrete, increase or decrease the water consumption, and use the falling hammer compaction method to obtain the mixture with different water contents. Dry density, and finally select the mix ratio with the highest dry density as the mix ratio of RCC. However, at present, the domestic RCC pavement mainly faces problems such as excessive consistency and insufficient slurry on the pavement surface during construction, and the compaction method is the most important The disadvantage is that it cannot reflect the consistency characteristics of the roller compacted concrete mixture, that is, it cannot measure the improved VC value of the roller compacted concrete (the time required for the half area of ​​the surface of the roller compacted concrete sample to produce slurry, and the record is accurate to 1s), so the The mix ratio determined by the compaction method similar to the soil needs to be tested for consistency to check whether the consistency can meet the engineering requirements of the improved VC value between 35s and 45s

In this way, not only the test steps are cumbersome, but also more test instruments and equipment are required, which is time-consuming and labor-intensive.

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