JPH03257205A - Manufacturing method for asphalt mixture - Google Patents

Abstract

PURPOSE:To improve durability by adding rubber latex to asphalt and aggregate which are being mixed with each other inside a mixer, and adjusting the asphalt quantity including rubber against the asphalt mixture so as to have a specified ratio in weight ratio. CONSTITUTION:Aggregate of which passing weight ratio through a sieve with a mesh dimension of 2.5mm is under 20% and asphalt are mixed inside a mixer of an asphalt plant. Next, rubber latex of 3-30% in weight ratio, 1.5-20% in conversion to solid rubber quantity against pure asphalt is added into the mixer. Then, the aggregate, the asphalt and the rubber latex are mixed with each other, the rubber latex is mixed inside the mixer against asphalt mixture, and asphalt quantity including rubber against the mixture is adjusted so as to exceed 5.5% in weight ratio and moreover to become less than 8.0%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an asphalt mixture using a so-called single-grain aggregate having a weight passing through a 2.5-mesh sieve of 20% or less.

[Conventional technology]

Considering the rate of paving in cities in recent years, water permeability and
The increase in road surfaces that do not have water retention properties increases the risk of localized disasters, even if drainage is treated using side gutters. In addition, with conventional asphalt pavement, there is a risk that safe and comfortable driving of vehicles may be impaired, such as hydroplaning during rain or visibility obstruction due to water splashing on the roadway.

Therefore, there is a desire for a pavement with excellent water permeability, and cement-concrete pavements such as "Vermiacon (Trademark Registration No. 1987890)" developed by the applicant are being put into practical use. .

However, asphalt pavement with such excellent water permeability has not yet been put into practical use.The porosity of an asphalt mixture that can be expected to have sufficient water permeability is thought to be approximately 18% or more. Conventional water-permeable asphald mixtures can only achieve a porosity of around 15%, and they quickly become clogged and cannot be expected to have sufficient water permeability. In recent years, asphalt mixtures with a porosity of 18% or more have been designed for roadways in Europe and America. There, self-calling method 2.
It is said that it is better to use so-called single-grain aggregate with a weight ratio of 20% or less passing through a 5ms+ sieve. With this aggregate blend, the amount of asphalt that can be contained and applied remains at about 3.5 to 5.5% using conventional mixing methods. Moreover, since the amount of asphalt is small and the porosity is high, the asphalt mixture is subject to deterioration due to the penetration of air and ultraviolet rays, resulting in problems such as plundering of aggregate.

[Problem to be solved by the invention]

In order to improve this, it is necessary to mix as much asphalt as possible to thicken the asphalt coating on the surface of the aggregate. However, in the conventional mixing method, when the amount of asphalt is increased, the asphalt sag from the coarse aggregate surface of the mixture together with the fine aggregate due to the high temperatures during mixing in the asphalt plant, transporting the asphalt mixture, and paving, resulting in the above-mentioned problems. As a result, the amount of asphalt that can be contained in the mixture remains at about 3.5 to 5.5%.

[Means to solve the problem]

The purpose of the present invention is to mix asphalt into a mixture at a mixing rate that exceeds the conventional wisdom without dripping, and to produce an asphalt mixture that has weather resistance, durability, and water permeability. The goal is to devise a method to do so.

As a result of the inventor's earnest efforts, in a method for producing an asphalt mixture using so-called single-grain aggregate, the asphalt and aggregate being mixed in the mixer of an asphalt plant are mixed at a weight ratio of 3 to 30 to pure asphalt. %, 1.5 to 20% rubber latex in terms of solid rubber amount is added so that the amount of asphalt containing rubber is more than 5.5% and less than 8.0% by weight based on the asphalt mixture. If the asphalt mixture is adjusted to produce the rubber asphalt on the surface of the aggregate,
The amount of asphalt that is conventionally known (3.5~5.
It has been observed that more than 5% of asphalt can be incorporated into asphalt mixtures without sag.

By adding rubber latex, the stabilizers, surfactants, and moisture in the latex form bubbles in the asphalt to stabilize it, and the cohesive force of the rubber acts more effectively, so the asphalt does not sag. This is thought to be able to prevent falling. In addition to the above-mentioned plant mix method, there is also a premix method for mixing rubber latex, but the latex does not foam with the premix type rubber-containing asphalt used in conventional dense-grained asphalt mixtures. Therefore, dripping cannot be prevented.

〔Example〕

As shown in Table 1, the asphalt mixture according to the method of the present invention has two types of aggregate compositions, and the method for measuring the degree of sagging is as follows:
According to e5t. The measured value is calculated as follows.

(1) Measure the weight W1 of the beaker.

(2) Asphalt mixture (1 to 1.1
kg) and leave it at 180℃ for 2 hours.

(3) After returning to room temperature, remove the asphalt mixture and measure the weight W2 of the beaker.

(4) The amount of asphalt in the asphalt mixture is A.

Then, degree of sag (%) = (W, -W,)/As X 10
0 [Effects of the Invention] From the measurement results of the degree of sagging as described above, it can be seen that according to the method for producing an asphalt mixture according to the present invention, although it boasts a high porosity that achieves water permeability, it does not deteriorate due to the penetration of air or ultraviolet rays, and does not suffer from wind and rain. It is clear that it is possible to provide asphalt mixtures that are resistant to deterioration caused by, are weather resistant and durable.

[Brief explanation of drawings]

1 and 2 are diagrams showing the relationship between the degree of sagging and the amount of latex, and FIG. 3 is a diagram showing the relationship between the degree of sagging and the amount of asphalt.

Claims (1)

[Claims] The weight ratio passing through a sieve with a mesh size of 2.5 mm is 20.
% or less, the asphalt and aggregate being mixed in the mixer of the asphalt plant are mixed with 3 to 30% by weight of pure asphalt, converted to the amount of solid rubber. Add 1.5 to 20% rubber latex,
An asphalt mixture prepared by adjusting the amount of asphalt containing rubber to the asphalt mixture so that the weight ratio is more than 5.5% and less than 8.0%, and producing the rubber-containing asphalt on the surface of the aggregate. Production method.