Quality control of highway micro-surfacing construction
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Quality control of highway micro-surfacing construction
Release Time:2023-12-08
Micro-surfacing is a preventive maintenance technology that uses a certain grade of stone chips or sand, fillers (cement, lime, fly ash, stone powder, etc.) and polymer-modified emulsified asphalt, external admixtures and water in a certain proportion. Mix it into a flowable mixture and then evenly spread it over the sealing layer on the road surface.
Quality control of highway micro-surfacing construction_1Quality control of highway micro-surfacing construction_2
Analysis of pavement structure and causes of pavement diseases
(1) Control of raw material quality
During the construction process, the control of raw materials (coarse aggregate diabase, fine aggregate diabase powder, modified emulsified asphalt) starts with the entry materials provided by the supplier, so the materials provided by the supplier must There is a formal test report. Furthermore, the materials are comprehensively inspected in accordance with relevant standards. During the construction process, the quality of the raw materials must also be analyzed. If there is any doubt, the quality must be randomly checked. In addition, if changes in raw materials are found, the imported materials must be re-tested.
(2) Control of slurry consistency
In the process of proportioning, the water design of the slurry mixture has been determined. However, according to the influence of the humidity on site, the moisture content of the aggregate, the temperature of the environment, the moisture content of the road, etc., the site often needs to adjust the slurry according to the actual situation. The amount of water used in the slurry mix is ??adjusted slightly to maintain the consistency of the mix suitable for paving needs.
(3) Micro-surface demulsification time control
During the highway micro-surfacing construction process, an important reason for quality problems is that the demulsification time of the slurry mixture is too early.
The uneven thickness, scratches, and disunity of asphalt caused by demulsification are all caused by premature demulsification. In terms of the bond between the sealing layer and the road surface, premature demulsification will also be very detrimental to it.
If it is found that the mixture is demulsified prematurely, an appropriate amount of retarder should be added to change the dosage of the filler. And turn on the pre-wet water switch to control the breaking time.
(4) Control of segregation
During the paving process of highways, segregation occurs due to reasons such as thin paving thickness, thick mixture gradation, and marking line position (smooth and with a certain thickness).
During the paving process, it is necessary to control the paving thickness, measure the paving thickness in time, and make timely adjustments if any deficiencies are found. If the gradation of the mixture is too coarse, the gradation of the slurry mixture should be adjusted within the gradation range to improve the segregation phenomenon at the micro surface. At the same time, the road markings to be paved should be milled before paving.
(5) Control of road paving thickness
In the paving process of highways, the paving thickness of thinner mixture is about 0.95 to 1.25 times. In the grading range, the curve should also be closer to the thicker side.
When the proportion of large aggregates in the aggregate is large, it must be laid thicker, otherwise the large aggregates cannot be pressed into the sealing layer. Moreover, it is also easy to cause scratches on the scraper.
On the contrary, if the aggregate is fine during the proportioning process, then the paved road surface must be paved thinner during the paving process of the highway.
During the construction process, the thickness of the paving must also be controlled and tested to ensure the amount of slurry mixture used in highway paving. In addition, during inspection, a vernier caliper can be used to directly measure the slurry seal on the micro-surface of the newly paved highway. If it exceeds a certain thickness, the paver box must be adjusted.
(6) Control of highway appearance
For micro-surface paving on highways, the structural strength of the road surface must be tested in advance. If looseness, waves, weakness, potholes, slurry, and cracks appear, these road conditions must be repaired before sealing construction.
During the paving process, be sure to keep it straight and ensure that the curbs or roadsides are parallel. In addition, when paving, the paving width should also be ensured, and the joints should be placed as far as possible on the lane dividing line to control the stability of the mixing and prevent the materials from prematurely separating in the paving box to ensure that they are The amount of water during the process is even and moderate.
In addition, all materials must be screened during loading to remove oversized particles, and defects must be smoothed in time during the filling process to keep their appearance smooth and consistent.
(7) Control of traffic opening
The shoe mark test is a commonly used inspection method for highway opening quality during micro-surface highway maintenance. That is to say, put the person's weight on the root or bottom of a shoe and stand on the sealing layer for two seconds. If the aggregate is not brought out or stuck to the person's shoe when leaving the sealing layer surface, it can be considered as micro surface. After the maintenance work is completed, it can be opened to traffic.