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Factors related to displacement of drying drum in asphalt mixing station - 29 Aug 2019 09:00



Regardless of the type of asphalt mixing plant equipment, the drying drum is one of the necessary equipment.

Typically, a rotating drying drum is a balancing system in motion.

The drum rotates the drying drum through the driving ring gear between the two rolling rings to ensure that the drum is in a state of dynamic balance, and if there is an accidental influence, the drum will be displaced.

After the displacement of the drying drum of the asphalt mixing station will easily lead to increased friction and increased wear, what are the reasons for this?

The first reason is that the temperature difference causes deformation.

The reason why the temperature will be different is usually caused by these kinds of conditions: 1. Improper operation. When the temperature reaches the standard, the drying drum is not deformed due to timely feeding; 2. After the production is stopped, the shutdown is too early to cause the deformation of the drying cylinder; The asphalt mixing station suddenly has a power outage during the production process.

The second reason may be that an abnormality has occurred inside the drying drum.

The drying drum of the asphalt mixing station consists of different parts. During the production process, due to the collision and friction between different parts in the cylinder, the internal parts are easily damaged or dropped in the long run, breaking the dynamics of the drum. balance.

Therefore, inspections should be carried out on a regular basis and in a timely manner.

For the third reason, there is no regular inspection work.

Because the parts will loosen during long-term use, this looseness will gradually lead to the movement of the rolling ring, which will also break the dynamic balance of the drying drum.

In another case, since the drying drum does not have a displacement along the longitudinal axis of the cylinder for a long time, it is presumably because the rolling ring and the tug only temporarily maintain the frictional driving of the surface, and if damage occurs, the asphalt will also be caused. The dynamic balance of the drying drum of the mixing station was destroyed.

The fourth reason is that there is no leveling during the installation process.

This is also a relatively easy to ignore factor. Because the foundation is not flat, the roller chassis is not on the same level, and it is easy to cause the dynamic balance state of the drying drum of the asphalt mixing station to be damaged. - Comments: 0

Technical advantages of the process of emulsifying modified asphalt fiber gravel seal - 26 Aug 2019 09:00



Technical advantages of the process of emulsifying modified asphalt fiber gravel seal
(1) Good stress absorption and dispersion ability
The fiber asphalt gravel seal with unique structure of network winding effectively improves the tensile, shear, compressive and impact strength of the seal due to the high tensile strength and high modulus of elasticity of the fiber itself.

On the one hand, the large-area dispersion of the fiber asphalt gravel seal reduces the tension of the lower layer and effectively suppresses the crack generation; on the other hand, it absorbs and disperses the reflection stress on the original crack of the asphalt pavement, and eliminates the crack of the old asphalt pavement. The stress concentration generated by the tip can effectively suppress the occurrence of reflection cracks, effectively prevent the road surface damage caused by excessive load on the vehicle, and greatly improve the service life of the road.

(2) High wear resistance
After the construction of the fiber asphalt gravel sealing equipment, the gravel aggregate is spread immediately after it, and the aggregate after the spreading enters the mesh structure formed by the fiber and the asphalt binder. After compaction, the aggregate is combined with the mesh. The structure is tightly wrapped to form a composite mechanical interlocking system. The fibers, asphalt and aggregate are closely connected, which effectively inhibits the slippage and shedding of the aggregate.

Therefore, the use of fiber asphalt gravel seal layer for wear layer construction can greatly improve the wear resistance of the road surface and prolong the service life.

(3) Water resistance
Since the emulsified asphalt and the glass fiber or basalt fiber are sprinkled (sprayed) by a fiber asphalt sealing machine, the fiber and the asphalt are effectively combined into a mixture, and the waterproof performance of the original asphalt pavement can be improved, and crack generation and development can be prevented. Thereby producing the desired adhesion and having a good waterproof effect.

(4) High temperature stability
Combined with the formation mechanism of the fiber asphalt gravel seal layer, the structure is a layer of asphalt + layer fiber + a layer of asphalt continuous construction + a layer of gravel formed by an interactive dense network winding structure.

The continuous spreading of the two layers of asphalt further improves the sealing property of the sealing layer. In addition, the fibers which play the role of reinforcement and bridging in the structure have a strong adsorption effect on the two layers of asphalt binder before and after, and it can be easily adsorbed. The oil in the asphalt increases its viscosity and adhesion, can effectively prevent the flow of asphalt, and forms a dense protective film on the original road surface, which acts as a high temperature stability, toughening and cracking resistance to the asphalt, thereby avoiding high temperature. The pavement damage caused by oil flooding has better protected the early destruction of the road water infiltration and stabilized the life of the road.

(5) Construction quickness
Accelerating maintenance construction speed and shortening open transportation time are also one of the criteria for measuring the advanced nature of road maintenance technology.

The fiber asphalt gravel sealer completes two layers of asphalt spreading and one layer of fiber spreading on one piece of equipment.

After the asphalt and fiber are sprinkled (spreaded), the gravel spreader immediately carries a layer of gravel and immediately completes the construction of the fiber asphalt gravel seal.

This continuous construction process greatly shortens the maintenance time of the asphalt pavement and shortens the time for opening traffic.

The traffic can be opened at a speed limit one hour after the construction in the summer high temperature period.

The fiber asphalt gravel sealing process with the above excellent performance can be widely applied to road construction and maintenance.

For example, it can be used as a stress absorbing layer to prevent reflection cracks; the wear-resistant layer of the old asphalt pavement is used for preventive maintenance; the lower seal layer construction of various grades; the old cement pavement reconstruction, and the construction of the bridge waterproof layer.

Provide a powerful weapon for China's road maintenance business.

asphalt mixing plant - Comments: 0

Main points of supervision and control of ordinary highway asphalt mixing station - 23 Aug 2019 09:01



The quality of asphalt mixture directly determines the quality of asphalt pavement engineering. This paper discusses the main points of supervision work of ordinary highway asphalt mixing station in order to better monitor the quality of asphalt mixture.

Basic requirements for asphalt mixing plants
The asphalt mixing station must use a batch mixing machine. The quantity of the cold storage bins meets the mixing ratio requirements. Before the mixing production, the asphalt mixing machine weighing and measuring system should be calibrated and passed the acceptance of the relevant departments.

The mixing site is hardened with cement concrete to ensure smooth drainage.

The collection bin is equipped with a canopy, and the different materials are stored in different grades. The nameplate is clear, and the partition is separated by the partition to ensure that the materials are not mixed.

The asphalt mixing station has special qualification for testing and testing, and its personnel, equipment and regulations meet the requirements.

Safe Production
Safety production is the middle of all production work. In addition to the safety production banner, safety production banner, post responsibility card, safety operation code, etc., the asphalt mixing station should, more importantly, safety production for each employee. Pay close attention to safety education and earnestly implement safety production responsibilities.

In the pre-construction asphalt mixing station, the mixing equipment should be inspected and adjusted, and the key safety hazards such as boilers should be checked, and the lightning rod should be installed on the top of the highest storage tank.

Safety protection devices shall be provided for the parts of the work platform, feed bins, asphalt tanks, etc. that involve personal safety. The exposed parts of the transmission system shall have protective devices and safety inspection and protection devices.

Quality control of raw materials
The quality of raw materials is the basis of the quality of asphalt mixture. Before the production, various raw materials are strictly inspected. The main raw materials (asphalt) should have a factory material list. The detection frequency is as follows:
The mix design is first carried out before construction. The main test items are: 1 penetration degree, ductility (elastic recovery) and softening point of modified asphalt; 2 gradation test of fine aggregate, sand equivalent, apparent density;
3 grading test of coarse aggregate, needle-like particle content, mud content, crush value, apparent density, asphalt adhesion; 4 appearance, grading test, heating stability, hydrophilic coefficient, Liquid plastic limit, density.

The main testing items in the construction have the penetration degree, ductility (elastic recovery) and softening point of the modified asphalt.

The detection frequency is 1 time/car, and the sampling frequency is 20%; 2 the gradation test of the fine aggregate, the sand equivalent, the detection frequency is 1 time/400m3, the sampling frequency is 20%; 3 the grading test of the coarse aggregate, the needle Flaky particle content, sludge content, crushing value, apparent density, asphalt adhesion, detection frequency is 1 time / 400m3, sampling frequency is 20%; 4 appearance, grading test, heating stability of mineral powder, Hydrophilic coefficient, liquid plastic limit, density, detection frequency is 1 time / 400m3, sampling frequency is 20%.

Verification of asphalt mixture ratio
According to the asphalt mixture ratio reported by the asphalt mixing station, the mixing ratio of the asphalt mixture is verified in time, and the Marshall test is carried out according to the target mixing ratio determined by the asphalt mixing station to determine whether the mixing ratio meets the requirements of the construction technical specifications.

If necessary, a rutting test should be conducted to test the high temperature performance of the asphalt mixture.

As an asphalt mixing station supervisor, you should be fully familiar with the target mix ratio and production mix ratio, including asphalt content, mineral powder content and various mineral ratios, as well as the primary mix of the cold mix of the asphalt mixer and the secondary screening of the hot bin. Screening holes at all levels to prepare for adjusting the mix ratio of asphalt mixture production.

Supervision matters in production
1 Asphalt content, mineral gradation and Marshall test
Asphalt content, mineral grading and Marshall test are important indicators of the quality of asphalt mixture. Therefore, it is crucial to side by side and check the bitumen content of the asphalt mixture, mineral grading and Marshall test.

The detection frequency is 1-2 times per shift, and the tester of the asphalt mixing station is urged to attach the electronic strip printed by the burning furnace and the Marshall tester to the test report as an effective basis for the test data source.

The sampling frequency of the supervision is 20% of the asphalt mixing station, sent to the laboratory of the supervision center or a qualified test and inspection center for inspection, and provides data standards for road surface compaction inspection.

2 Heating temperature and mixing time of asphalt and mineral materials
There is no data directly on the asphalt mixer that directly shows the temperature of the finished asphalt mixture. Therefore, the temperature of the asphalt and the heating temperature of the ore should be closely monitored, including the temperature of the drum and the hot extraction temperature of the mineral, to infer the temperature of the finished asphalt mixture.

The mixing time of asphalt mixture is determined according to the specific conditions, and the aggregate is uniformly coated with asphalt. The production cycle of each batch of batch mixer should not be less than 45s (the dry mixing time should not be less than 5-10s) The mixing time of the modified asphalt and SMA mixture should be extended appropriately.

3 mine powder recycling rate
The recovery and utilization rate of the ore powder is required to be controlled within 25%, and the change in the proportion of recycled powder is used, including the change in the use of the recycled powder due to the difference in the dust removal effect, even if the dust removal effect is weakened without using the recycled powder. In fact, it can still be regarded as part of the recycled dust being used. Therefore, the asphalt mixing station should be urged to carry out regular dust cleaning and cleaning bags. In addition to avoiding the recovery of the mineral powder, it can also avoid the excessive temperature of the secondary auger. The machine fails and meets the requirements of environmental protection.

4 loading and transportation
The transporter should be loaded three times before, after, and three times, with the same height to prevent segregation. All trucks should be covered with heat preservation and anti-spray when leaving the factory.

5 factory temperature
Insert the digital thermometer with metal detector needle into the asphalt mixture of the finished vehicle, the depth is 15cm, to judge the ex-factory temperature of the asphalt mixture more accurately.

When the weather changes, the distance and the isochronous adjustment, the temperature can be appropriately adjusted within the specified range to ensure that the asphalt mixture can reach the optimal paving and rolling temperature during the unloading.

Each shift is tested 10 times and the temperature is as follows:
Asphalt mixture factory temperature (°C)
If the temperature of the asphalt mixture is too low, the flower will appear. If the temperature is too high, the asphalt will be burnt. The primary distribution of the cold material and the water content of the raw material should be controlled to ensure the normal working state of the burner, thus ensuring the factory temperature of the asphalt mixture. .

6 notes
1 combustion furnace correction coefficient determination
The accuracy of the furnace directly affects the judgment of the asphalt content. Before starting the construction, the qualified units should be regularly calibrated, and the correction factors for the different proportions of the different materials should be determined.

The determination of the combustion correction coefficient plays a crucial role in determining the asphalt content in the asphalt mixture. However, the current combustion correction coefficient determination method does not specify the operating procedures. The usual practices are as follows: (1) Accurately configure the selected Asphalt content and selected asphalt dosage ±0.
3% of the three groups of asphalt mixture; (2) placed in the furnace that has reached the set temperature for combustion to constant weight; (3) Calculate the loss rate of the asphalt mixture, using the average of the difference between the loss rate and the preset amount of asphalt Combustion coefficient.

Since there are many factors affecting the combustion correction coefficient, the combustion coefficient should be corrected frequently during construction. The combustion coefficient must be corrected in the case of changes in raw materials, changes in the composition of the mineral material, and changes in the recovery ratio of the recovered powder.

2 production mix adjustment
The primary material of the cold material is calculated according to the proportion of various materials in the target mix ratio, and the rotational speed of the batching motor of each cold silo and the height of the material door are calculated to determine the conveying amount of various materials.

If the primary material of the cold material is not accurate, the phenomenon of material waiting and flashing will occur. The tester should adjust the primary material of different raw materials according to the screening test data. The cylinder design has a matching ratio with the target mix ratio to ensure the mixing. Production stability and continuity.

After the primary cooling of the cold material is stabilized, the tester must perform a hot silo screening to determine the proportion of the different particle size materials in each hot silo.

During the production mixing process, the operator of the asphalt mixing station shall not adjust the number of revolutions of the batching motor of the cold silo, change the production mix ratio data, and cannot increase the productivity of the mixing station by means of skipping or feeding. - Comments: 0

How to determine the material of asphalt mixing plant? - 08 Aug 2019 09:00



Determining the material is a necessary stage in the design process of the asphalt mixing plant, and it is also one of the most critical steps, because the material will directly affect the use effect and service life of the entire equipment.

Generally, when we determine the material of the machine, it is usually based on the characteristics of the working medium, and of course the asphalt mixing plant.

If there are no special requirements, similar mixing equipment is made of carbon steel, which can be applied to most working conditions, as long as the temperature is not higher than 350 ° C, and the price is relatively low.

However, this material cannot be used in asphalt mixing plants. Asphalt is a very good temperature material, it does not meet the high temperature resistance, and the corrosion resistance of carbon steel is poor.

In view of the above requirements, a stainless steel asphalt mixer or a beryllium glass material can be used.

However, no matter which one, there is a finer material classification, so the specific model should be determined according to its own mixing conditions, stirring temperature and corrosiveness. - Comments: 0

What are the advanced features of the control system of the asphalt mixing plant? - 05 Aug 2019 09:00



Asphalt mixing plant mainly includes batching system, drying system, combustion system, hot material lifting, vibrating screen, hot material storage bin, weighing and stirring system, asphalt supply system, powder supply system, dust removal system, finished silo and control. The system and other parts, the control system is at the core, it controls all the actions of the asphalt mixing plant.

In addition to the basics, the control system of the asphalt mixing plant has many advanced functions. Due to the industrial control computer, I/O acquisition and high-precision weighing system, it can be controlled according to the asphalt production process and quality requirements. The software realizes automatic control of data collection and production, and records production data information in real time. Data management can be used to query/print multiple production reports.

The configuration of the asphalt mixing plant control system is also very scientific, reasonable selection, adhere to the principle of global procurement, international brand products as the main selection range, making the system overall stability, powerful, easy to operate.

What you see again is the software aspect of the asphalt mixing plant control system, which not only has the automatic moisture content conversion function, but also can automatically convert the total number of discs and the quantity of the discs, which helps to reduce the workload and the possibility of misoperation. .

At the same time, the control system of the asphalt mixing station can also automatically fill the name, automatically buckle and automatically adjust the ingredient parameters to improve the batching accuracy.

Together with its automatic continuous production function, the actual production efficiency of the mixing station is greatly improved. - Comments: 0

What factors will the asphalt mixing plant control system interfere with? - 02 Aug 2019 09:00



When we do some work, there may be some factors that may interfere with some factors.

For example, in the work, the asphalt mixing plant control system is susceptible to interference from some factors.

The so-called interference, also known as noise, refers to those electrical signals that are independent of the signal.

Interference may cause errors in the weighing system, communication interruptions, etc.

After summarizing and analyzing the previous production work, we found that the interference often encountered by the asphalt mixing plant control system usually includes four types, namely, the introduction of interference in the signal line, the introduction of alternating magnetic field by the actuator, and the introduction of lightning. Interference and leakage of charged body introduce interference.

In order to facilitate everyone's understanding, next, we will introduce these kinds of interference cases in turn.

Let me explain the first interference situation first.

In the control system of the asphalt mixing plant, if several signals are transmitted at the same time, there are some distributed capacitances between these signal lines. Under the influence of these factors, it is easy to cause some interference between each other, that is, Interference is introduced in other signal lines.

The second type of interference is related to the working environment.

When using an asphalt mixing plant, if there are some large-scale electrical equipment in the vicinity of it, the spark generated when the switch is closed and disconnected during the start-stop process will generate a large alternating magnetic field around it. Therefore, there will also be interference.

If these disturbances are large, it will affect the work of the system.

The third is mainly the influence of natural factors.

In our lives, there are many natural phenomena. Lightning strikes are one of them. Lightning strikes may cause large electromagnetic interference around the control system of the asphalt mixing plant, and may also introduce interference through various lines.

In addition, there is also a situation that can cause infection. In the working process of the asphalt mixing plant, if there are leakage problems of other charged equipment used, it will also cause great interference to its control system. - Comments: 0

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