The construction method of fiber-added asphalt concrete is basically the same as that of traditional asphalt concrete. It is divided into a process of incoming material inspection, selection of mixing equipment, mixing, paving and rolling, but there are also differences. Now the fiber-added asphalt The differences between concrete and traditional asphalt concrete construction technology are introduced.

(1) Precautions for selection of fiber-added asphalt concrete mixing equipment

1. Due to the addition of fibers, it is necessary to prolong the time of dry mixing and wet mixing to make the fibers evenly coat the mineral materials, and the production capacity of the mixing equipment will drop by 20%-30%, especially for some provinces in northern my country, where the winter temperature is very low. The opening time is often set in winter. This objectively determines the completion of the asphalt surface layer, that is, the construction of the asphalt surface layer must be completed before the temperature turns cold. The decline in the production capacity of mixing equipment leads to the extension of the construction period. For example, some construction units pave ordinary asphalt concrete with a daily output of 2.4-2.7km (single-layer single layer), while paving fiber-added asphalt concrete is only 1.5-1.8km (single-layer single layer), resulting in construction delays and weather changes. Cold is very unfavorable to ensure compactness and smoothness, so the mixing capacity of mixing equipment must be considered when planning construction or the construction of base and base should be accelerated to allow sufficient and reasonable construction time for asphalt surface construction. These factors must be taken into account when planning construction.

2. For the traditional continuous mixing equipment, it is necessary to add special fiber adding equipment, and because the proportion of fiber in the mixture is very small, the accuracy of the equipment will be an important aspect affecting the quality of mixing, and the unevenness of fiber mixing will also increase. As a result, the oil consumption of the mixture is too large or too small, which affects the quality of the project. Therefore, it is advisable to use traditional batch mixing equipment and manually add fibers, which is economical and easy to operate. Strict requirements should be imposed on the feeding workers to avoid More votes, missed votes.

(2) Requirements for mixing fiber-added asphalt concrete

1. Determine the mixing ratio of each tray of hot material bins, calculate the mass of each tray of mixture, calculate the fiber quality in each tray of mixture according to the fiber consumption determined by the target mixing ratio, and then carry out the fiber entering the site according to this quality Packed separately, the packaging bag can be a common polyethylene plastic bag on the market. During the packaging process, the accuracy of weighing is guaranteed. Fiber doping is shown in the schematic diagram:

2. The asphalt mixture should be trial-mixed according to the designed amount of asphalt. After the trial-mixing, samples should be taken for Marshall test, and the test value should be compared with the indoor mixing ratio test results to verify the rationality of the designed asphalt amount. If necessary, appropriate adjustments can be made :

3. Determine the appropriate mixing time. For ordinary asphalt mixture, the mixing time of each tray of batch mixing equipment is 30-60 seconds. The recommended mixing time is 25-30 seconds for dry mixing and 30 seconds for wet mixing. Good coverage shall prevail;

4. Determine the appropriate mixing and delivery temperature. The heating temperature of asphalt (both refers to petroleum asphalt, the same below) should be 130°C ~ 160°C, and the heating should not exceed 6 hours, and the heating should be used up on the same day, and it is not suitable to be heated multiple times to avoid aging sand. The heating temperature is 140°C ~ 170°C, the ore is not heated. The ex-factory temperature of asphalt mixture should be 130℃～160℃. When modified asphalt is used, it should be 10℃～15℃ higher than the upper limit of the above temperature. It is not necessary to adjust the temperature when adding fibers.

(3) Matters needing attention in compaction

The compaction procedure is divided into three processes: initial pressure, re-pressure and final pressure. The purpose of initial pressing is to level and stabilize the mixture, and at the same time create favorable conditions for re-pressing, which is the basis of pressing, so attention should be paid to the smoothness of compaction; the purpose of re-pressing is to make the mixture dense, stable, and shaped, and the mixture The degree of compaction depends on this process, so it must be closely connected with the initial pressure, and a heavy-duty road roller is generally used; the purpose of the final pressure is to eliminate wheel marks and finally form a flat compacted surface, so this process is not suitable for heavy-duty road rollers. Finish under, otherwise it will affect the flatness.

Use a 6-18-ton double-wheel roller or a 6-10-ton vibratory roller (with the vibrating device off) to press twice during the initial pressure. After the initial pressure, check the flatness and road crown, and repair it if necessary. If there is a shift during rolling, wait until the temperature is slightly lower before pressing; if there is a crack on the side of the ship, check the cause and take measures to correct it in time.

When re-pressing, use a 10-12-ton three-wheel roller, a 10-ton vibratory roller or the corresponding tire roller. It is advisable to roll 4-6 times until it is stable and there are no obvious wheel tracks.

Use a 6-8 ton vibratory roller (turn off the vibrating device) to press 2-4 times for final pressing to eliminate wheel tracks.

The viscosity of the asphalt mixture after adding fiber increases, and it should be added 1 to 2 times on the basis of the above-mentioned ordinary asphalt mixture rolling times, or increase the paving and rolling temperature, road roller and paver, to avoid temperature drop Too much to achieve the desired compaction effect.

Oil spots are generally not formed during the forming process of fiber-added asphalt concrete pavement, and the color and appearance are basically the same as ordinary asphalt concrete pavement.