During the construction of road crack sealing machines, the temperature control of crack sealing materials directly affects the sealing quality (such as adhesion, fluidity, and durability). The core principle to follow is "precise setting, dynamic monitoring, stable heat preservation, and environment adaptation". Refined control should be implemented in combination with equipment functions and material characteristics. The specific methods are as follows:
Precisely set the reference temperature according to the type of crack sealing material: Asphalt-based crack sealant (hot-melt type) usually needs to be heated to 160-180℃. This temperature range ensures good fluidity of the material without damaging its chemical properties; Polyurethane-based crack sealant (hot-melt type) should have its temperature controlled at 120-150℃ to prevent material aging and deterioration caused by high temperatures.
Adjust the temperature with reference to the material instruction manual, and make fine adjustments based on the ambient temperature: In low-temperature environments (5-10℃), the temperature can be appropriately increased by 5-10℃ to compensate for heat loss; In high-temperature environments (>30℃), the temperature can be reduced by 5℃ to prevent the material from becoming too thin and flowing.
Check the accuracy of the crack sealing machine's temperature controller. Ensure that the error between the displayed temperature and the actual temperature in the material tank is ≤±5℃ through calibration; For large-scale equipment with a digital display function, start the preheating program in advance and run it idly for 3-5 minutes to test whether the temperature rise curve is stable.
Confirm that the heating system (combustion chamber, electric heating tube) works normally without local overheating or uneven heating; For small hand-pushed equipment, check the flame size adjustment function; For large-scale equipment, test the sensitivity of the automatic temperature control start-stop mechanism.
Select crack sealing materials that are free of caking and not expired. Block-shaped materials need to be crushed in advance to avoid insufficient local heating caused by material accumulation; The feeding amount should not exceed 80% of the material tank capacity. Reserve space to facilitate thermal convection and stirring, and reduce temperature stratification.
Record the temperature in the material tank every 10-15 minutes during operation. Large-scale equipment can rely on its built-in temperature monitoring module to realize real-time early warning. When the temperature exceeds the set range by ±5℃, adjust the heating power in a timely manner.
Focus on monitoring the temperature of the material conveying pipeline and spray gun. Some equipment is equipped with a pipeline heat tracing device, which needs to ensure that its temperature is consistent with the temperature of the material tank to prevent the crack sealing material from cooling and solidifying during transportation, resulting in pipeline blockage.
Turn on the equipment's built-in stirring function (or perform manual regular stirring once every 20 minutes) to avoid local overheating of the material at the bottom of the tank due to long-term heating and incomplete melting of the material at the top.
For large-scale towed crack sealing machines, the traveling speed can be adjusted to match the material discharge rate to avoid local material overheating caused by prolonged equipment stay or sudden temperature drop due to excessive discharge speed.
In high-temperature and strong-light environments, cover the material tank with a heat insulation cover to reduce abnormal temperature rise caused by direct sunlight; In low-temperature or windy weather, build a temporary wind shelter in the operation area. At the same time, shorten the time from material discharge to crack filling to reduce heat loss.
Suspend construction in rainy, snowy weather or when the temperature is below 5℃ to prevent environmental moisture and low temperature from jointly affecting the temperature stability and adhesion effect of the material.
After the operation is completed, turn off the heating system. When the temperature of the material tank drops below 80℃, export the remaining crack sealing material to a special container for recycling. This avoids potential safety hazards caused by high-temperature materials directly contacting the ground and prevents the material from caking due to sudden cooling, which affects its secondary use.
Clean the residual crack sealing material on the surface of the temperature control sensor to prevent impurities from adhering and affecting the accuracy of subsequent temperature detection; Descaling the heating elements (such as burner nozzles and electric heating tubes) to ensure stable heating efficiency in the next use.
For fuel-type crack sealing machines, check the remaining fuel in the fuel tank to avoid heating interruption caused by insufficient fuel supply, which affects temperature control.
It is strictly forbidden to excessively increase the temperature in pursuit of fluidity. Asphalt-based materials are prone to aging when the temperature exceeds 200℃, which reduces the bonding strength and durability; Overheating of polyurethane materials may cause abnormal curing speed, leading to cracking of the sealing layer.
If a fault occurs in the equipment temperature control system (such as temperature out of control, display failure), stop the operation immediately, check the fault after the material cools down, and do not continue construction until the fault is eliminated.
Different types of crack sealing materials shall not be mixed for heating to avoid disordered temperature requirements caused by component reactions, which affects the construction quality.
Chinese
