Method for rapid repair of road cracks based on geopolymer modified asphalt
By using geopolymer-modified asphalt in conjunction with milling, mixing, and paving steps, the problem of early damage to asphalt pavements has been solved, enabling rapid and low-cost pavement repair and waste resource utilization, thereby improving pavement performance and lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGXI UNIV
- Filing Date
- 2023-04-04
- Publication Date
- 2026-05-22
Smart Images
Figure BDA0004160667870000011
Abstract
Description
Technical Field
[0001] This invention belongs to the field of road surface treatment technology, and in particular relates to a rapid repair method for road cracks based on geopolymer-modified asphalt. Background Technology
[0002] Asphalt pavement offers excellent driving comfort and stability, and its ability to open to traffic quickly and its ease of maintenance and repair have gradually made it the primary form of highway pavement. However, practical engineering experience shows that traditional asphalt pavement is already overwhelmed by increasing traffic volume and harsh environmental factors. Soon after opening to traffic, it develops numerous defects such as cracking, loosening, potholes, shoving, bulging, and rutting, affecting not only the continuity of the pavement but also endangering vehicle safety. Therefore, repairing asphalt pavement defects is necessary to reduce premature pavement damage, improve highway engineering quality, and extend service life.
[0003] Timely repair of pavement cracks can not only slow down early damage and improve the overall service quality of highways, but also enhance the local strength and load-bearing capacity of the pavement to a certain extent, ensuring its smoothness and durability. Therefore, exploring a new type of modified asphalt that is high-performance, economical, and environmentally friendly has significant economic and engineering value in improving asphalt pavement quality, extending pavement service life, and reducing road costs. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a rapid repair method for road cracks based on geopolymer modified asphalt that is quick to construct, effective, and inexpensive.
[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0006] A rapid repair method for road cracks based on geopolymer-modified asphalt is proposed, using geopolymer-modified asphalt as the repair material. The geopolymer-modified asphalt uses SBS-modified asphalt as the base material and geopolymer-modified powder as the modifier, and is prepared in the following weight proportions: 94-96 parts SBS-modified asphalt and 4-6 parts geopolymer-modified powder; wherein the geopolymer-modified powder is made from the following materials in parts by weight:
[0007]
[0008] The modulus of water glass is 1.0–1.5; the concentration of NaOH solution is 4.5–5.5 mol / L; metakaolin is dehydrated from kaolin calcined at 800–900℃, with a mesh size of 700–800 mesh; slag powder has a mesh size of 400–500 mesh; silicon powder is high-purity single-crystal silicon powder with a mesh size of 400–600 mesh; and steel slag powder has a mesh size of 400 mesh.
[0009] The ratio of steel slag powder to silicon powder is 1:1.
[0010] Geopolymer modified powder is prepared as follows: Kaolin powder, slag powder, steel slag powder, and silicon powder are mixed to form a geopolymer solid powder; an alkali activator is mixed with the geopolymer solid powder, stirred, poured into a mold, sealed, cured, demolded, crushed with a pulverizer, and sieved to obtain the geopolymer modified powder; the alkali activator is prepared as follows: NaOH solution and water glass solution are mixed and prepared, sealed and stored for 24 hours before use; curing is performed by placing it in a constant temperature and humidity chamber at 80℃ and 70% for 12–24 hours.
[0011] The above quick repair method includes the following steps: <1> Road milling, <2> Mixing the ingredients, <3> Mixed material transportation <4> Spreading and compaction.
[0012] step <1> Perform the following steps: Use a milling machine to mill the severely damaged areas and remove loose aggregates and other debris from the groove.
[0013] step <2> The mixing of asphalt mixtures shall be carried out as follows: The mixing of asphalt mixtures shall be completed by the mixing plant. Before the asphalt mixing plant is started, the SBS modified asphalt shall be heated in advance, and then hot asphalt and geopolymer modified powder, mineral powder and aggregate shall be added according to the proportion and mixed. The mineral powder shall be limestone mineral powder with a mesh size of 400-600 mesh. The aggregate shall be diabase aggregate, and the median value of the aggregate composition range of AC-13 shall be taken.
[0014] The asphalt is heated to 160 degrees Celsius; during mixing, the dry mixing time is no less than 10 seconds and the wet mixing time is 35 seconds; the discharge temperature after mixing is in the range of 150 to 160 degrees Celsius.
[0015] step <3> The loading process should be carried out as follows: The truck should be loaded in three stages. The first loading should be done near the front of the truck bed, the second near the rear door, and the third in the middle of the truck bed.
[0016] step <4> The following procedures should be followed: the construction temperature should not be lower than 10 degrees Celsius, the paving temperature should be controlled between 165 and 170 degrees Celsius, the entire width should be paved in one go without segregation, the paving speed should not exceed 3 to 4 m / min, the well-mixed material should be poured into the pit, the mixture should be smoothed with putty knife or other tools, and leveled with a plate compactor or road roller.
[0017] To address the current problems in road crack repair, the inventors have developed a rapid repair method for road cracks based on geopolymer-modified asphalt. This method uses geopolymer-modified asphalt as the repair material. The geopolymer-modified asphalt uses SBS-modified asphalt as the base material and geopolymer-modified powder as the modifier, prepared in the following weight proportions: 94-96 parts SBS-modified asphalt and 4-6 parts geopolymer-modified powder. The geopolymer-modified powder is composed of water glass, NaOH solution, metakaolin, slag powder, silica fume, steel slag powder, and water. This method uses geopolymer as an asphalt additive blended with SBS-modified asphalt, offering advantages such as environmental friendliness and reduced costs. Tests show that compared to ordinary asphalt mixtures, the geopolymer-modified asphalt obtained in this invention has better high-temperature thermal stability, crack resistance, and long service life, effectively preventing early rutting, shoving, and water damage problems in asphalt pavements. The rapid repair method established based on this method has the characteristics of quick construction, good effect and low cost. Moreover, it realizes the resource recycling of new industrial waste and opens up a new direction for asphalt modification. Detailed Implementation
[0018] Example 1: Preparation of Geopolymer Modified Powder
[0019] Take 20 kg of metakaolin powder, 12 kg of slag powder, 4 kg of steel slag powder, and 4 kg of silica powder and mix them to form a geopolymer solid powder. Take 16 kg of alkali activator and 25 kg of geopolymer solid powder and mix them. After stirring for 15 minutes, pour the mixture into a mold, seal it, and cure it (place it in a constant temperature and humidity chamber at 80℃ and 70% humidity for 12-24 hours). After demolding, crush it with a pulverizer and sieve it through a 0.075 mm sieve to obtain the geopolymer modified powder. The alkali activator is prepared as follows: take 7 kg of 5 mol / L NaOH solution and 13 kg of water glass solution with a modulus of 1.2 and mix them. Seal and store it for 24 hours before use.
[0020] Among them, metakaolin is made by dehydrating kaolin calcined at 800-900℃, with a mesh size of 700-800 mesh; slag powder has a mesh size of 400-500 mesh; silicon powder is high-purity single-crystal silicon powder with a mesh size of 400-600 mesh; and steel slag powder has a mesh size of 400 mesh.
[0021] The geopolymer was tested and found to have a compressive strength of 32.1 MPa and a flexural strength of 5.06 MPa.
[0022] Example 2: Preparation of Geopolymer-Modified Asphalt
[0023] Take 5 kg of geopolymer modified powder from Example 1 and mix it with 95 kg of SBS modified asphalt. Stir at high speed for 5 minutes until the mixture is homogeneous to obtain geopolymer-based modified asphalt.
[0024] Tests showed that the penetration of the geopolymer-modified asphalt was 55 mm, the softening point was 56 degrees Celsius, the ductility was 7.8 cm, and the elastic recovery rate was 64%.
[0025] Example 3: Rapid Repair Method for Road Cracks of the Present Invention
[0026] <1> Road milling
[0027] The following steps should be taken: Before the maintenance work begins, investigate the original road surface damage and mark the extent and depth of the damage; use a milling machine to mill the severely damaged areas and remove loose aggregates and other debris from the trenches.
[0028] <2> Mixing
[0029] The mixing of asphalt mixtures is completed by a mixing plant, which mainly consists of a feed hopper, conveyor belt, mixer, storage hopper, asphalt storage tank, and control room. The entire mixing process is controlled from the control room. Before starting the asphalt mixing plant, the SBS modified asphalt should be preheated to the specified temperature (generally around 160 degrees Celsius). Then, hot asphalt, geopolymer modified powder, aggregate, and limestone powder are added and mixed. The recommended asphalt-aggregate ratio is 4%–7%, the recommended geopolymer content is 4%–6%, depending on the needs, and the mineral powder content is 3%–5%. On-site mixing is recommended to reduce transportation time. During mixing, the dry mixing time should be no less than 10 seconds, and the wet mixing time is generally 35 seconds. The discharge temperature after mixing should be between 150 and 160 degrees Celsius.
[0030] The limestone powder has a mesh size of 400-600 mesh; the aggregate is diabase aggregate, and the median value of the AC-13 aggregate range is taken as the aggregate composition of the mineral.
[0031] <3> Mixed material transportation
[0032] Truck loading should be done in three stages: the first loading should be near the front of the truck bed, the second near the rear door, and the third in the middle of the truck bed. During transportation, the asphalt mixture should be covered to reduce heat loss during the mixing and waiting process and to ensure the correct construction temperature.
[0033] <4> Paving and compaction
[0034] This asphalt mixture is not suitable for construction in cold or rainy climates. The construction temperature should not be lower than 10 degrees Celsius, with the optimal construction temperature above 20 degrees Celsius. If the outside temperature is low, the mixing and paving temperature of the mixture can be appropriately increased, with the paving temperature ideally controlled between 165 and 170 degrees Celsius. Paving should be done in one continuous pass across the entire width, without causing segregation, and the paving speed should generally not exceed 3 to 4 m / min. During paving, care should be taken to open the rear door of the receiving hopper as wide as possible between each truck unloading, and the mixture should be paved as continuously as possible. The well-mixed mixture should be poured into the pit, smoothed with a putty knife or similar tool, and then leveled with a plate compactor or roller.
Claims
1. A rapid repair method for road cracks based on geopolymer-modified asphalt, characterized in that... Geopolymer-modified asphalt is used as the repair material; the geopolymer-modified asphalt uses SBS-modified asphalt as the base material and geopolymer-modified powder as the modifier, and is prepared in the following parts by weight: 94-96 parts SBS-modified asphalt and 4-6 parts geopolymer-modified powder; wherein, the geopolymer-modified powder is made from the following materials in parts by weight: 0.7 to 0.75 parts water glass 1.7–2.0 parts of NaOH solution Metakaolin 1.4–1.6 parts Slag powder 0.8-0.95 parts 0.2 to 0.35 parts of silicon powder 0.2–0.35 parts of steel slag powder The modulus of the water glass is 1.0–1.5; the concentration of the NaOH solution is 4.5–5.5 mol / L; the metakaolin is obtained by dehydrating kaolin calcined at 800–900℃, and has a mesh size of 700–800 mesh; the slag powder has a mesh size of 400–500 mesh; the silicon powder is high-purity single-crystal silicon powder, with a mesh size of 400–600 mesh; and the steel slag powder has a mesh size of 400 mesh. The ratio of steel slag powder to silicon powder is 1:1; The geopolymer-modified powder is prepared as follows: Kaolin powder, slag powder, steel slag powder, and silicon powder are mixed to form a geopolymer solid powder; an alkali activator is mixed with the geopolymer solid powder, stirred, poured into a mold, sealed, cured, demolded, crushed with a pulverizer, and sieved to obtain the geopolymer-modified powder; wherein, the alkali activator is prepared as follows: NaOH solution and water glass solution are mixed and prepared, sealed and stored for 24 hours before use; the curing is performed by placing it in a constant temperature and humidity chamber at 80℃ and 70% humidity for 12–24 hours. The law specifically includes the following steps: <1> Road milling, <2> Mixing the ingredients, <3> Mixed material transportation <4> Paving and compaction; step <1> Perform the following steps: Use a milling machine to mill the severely damaged areas and remove loose aggregates and other debris from the groove; step <2> The mixing of asphalt mixtures shall be carried out as follows: The mixing of asphalt mixtures shall be completed by the mixing plant. Before the asphalt mixing plant is started, the SBS modified asphalt shall be heated in advance, and then hot asphalt, geopolymer modified powder, mineral powder and aggregate shall be added according to the proportion and mixed. The mineral powder shall be limestone mineral powder with a mesh size of 400-600 mesh. The aggregate shall be diabase aggregate, and the median value of the AC-13 aggregate mix shall be taken as the mineral aggregate mix. The asphalt is heated to 160 degrees Celsius; during the mixing process, the dry mixing time is not less than 10 seconds and the wet mixing time is 35 seconds; the discharge temperature after mixing is in the range of 150 to 160 degrees Celsius. step <3> The loading of the truck should be carried out in three stages: the first loading should be done near the front of the truck bed, the second loading should be done near the rear door of the truck bed, and the third loading should be done in the middle of the truck bed. step <4> The following procedures should be followed: the construction temperature should not be lower than 10 degrees Celsius, the paving temperature should be controlled between 165 and 170 degrees Celsius, the entire width should be paved in one go without segregation, the paving speed should not exceed 3 to 4 m / min, the well-mixed material should be poured into the pit, the mixture should be smoothed with putty knife or other tools, and leveled with a plate compactor or road roller.