Concrete causes bleeding and segregation problems and solutions

1、the reason
(1) When the cement fineness is large, it is easy to leak water. The content of C3A in the cement is low and the bleeding is easy. The standard consistency of the cement is small and the volume of water is easily bleeding.
(2) The amount of cement is small and easy to bleeding.
(3) Low-grade cement is more prone to bleeding (with same amount) than high-grade cement concrete.
(4) Concrete of the same grade, high-grade cement concrete is more prone to bleeding than concrete of low-grade cement.
(5) The concrete with large water consumption is prone to bleeding and segregation.
(6) The temperature of the concrete mixture is too high, especially in summer, the temperature is high, the hydration reaction is fast, and the slump loss is large.
(7) Concrete with low strength grade is prone to bleeding.
(8) Concrete with small sand rate is prone to bleeding and segregation.
(9) The continuous particle size of gravel is smaller than that of single gravel.
(10) The water retention, thickening, and poor air-entraining properties of concrete admixtures tend to cause bleeding.
(11) Concrete with excess concrete admixture is prone to bleeding and segregation.
(12) The stirring performance of some models of mixing trucks is not good. After a certain distance of transportation, the concrete mixture will obviously float up when it is discharged.
(13) Concrete mixer trucks contain stagnant water in the mixing drum, and they are not drained before loading or during the transportation process, any water is added to the mixing container.
2、the solution
(1) The fundamental way is to reduce the unit water consumption.
(2) increase the sand rate, select a reasonable sand rate.
(3) In hot summer, take measures to reduce the temperature of the concrete mixture.
(4) Increase the amount of cement or add appropriate amount of Class I and II fly ash.
(5) Continuous grading of gravel with small needle-like content.
(6) Improve the performance of concrete admixtures to make them have better water retention and thickening, or reduce the amount of concrete admixture (only on site). If the admixture volume of the concrete admixture is reduced at the mixing station, concrete may be added. New problems with rapid slump loss.
(7) Before the concrete mixing truck is unloaded, the mixing drum should be rotated at medium and high speed so that the concrete mixture is unloaded evenly.
(8) Strengthen management. Before cleaning the trucks, they must be drained before they are filled. After loading, it is forbidden to add water to the mixing bowl.
3、 sum up experience
Concrete is prone to bleeding and segregation problems. Through learning and experimentation, we have concluded a set of solutions to solve problems in combination with actual conditions. Such as optimizing the mix ratio, strengthening the approach to raw material testing, and strengthening site management. Eliminating the phenomenon of arbitrarily increasing water consumption due to poor site management at the mixing plant.

Matters needing attention in JS1000 concrete mixer work

1,concrete mixer should stay after the normal operation of the motor, then push on the total clutch, empty machine running for 2 – 3 minutes, such as concrete mixer mixing drum rotation is smooth, not beating, not running deviation, no abnormal effect, hopper up and down and discharge door opening and closing are flexible, can work.
2,   the work of the operator must wear masks, sleeves.
3,   it is strictly prohibited to repair and maintenance in operation, are not allowed to use tools into the mixing drum pick ash slurry or discharge.
4,   when the concrete mixer in full-load operation suddenly power failure or failure, the first switch should be pulled down, with human will be clear of concrete mixing drum. Do not allow to start the mixer with load, in case of starting the current is too large and damage the motor.
5,   the operation of the electric mixer must easily stand on the mat with wood operation on the operating table.
6,   the power of the concrete mixer in more than 5 kilowatts, must be installed starter. When starting, such as arc, blaze or voltage drop suddenly, should immediately stop starting, cut off the power supply, check and repair.
7,   feed hopper rises, it is strictly prohibited to work under the hopper or traffic; Hopper of foundation pit need to clean up or under the hopper inspection, must contact the operator and stay hopper with chain buckle rear can be allowed.
8,   at the bottom of the foundation pit to spread straw bag, as hopper pillow. When the hopper falls to close to the ground, should stop slightly, and then put to the end, so as not to drop too fast and damage the hopper.
9,   feed hopper rises, that is, should open the water valve into part of the water, such as material into such as cylinder before water.
10,  power outage maintenance, must remove the fuse in the switch, and lock the brake box, in order to ensure production safety.

The use and characteristics of the batching station

Batching plant is an important component of the whole mixing equipment, it is mainly used to store aggregate, accurate measurement and timely supply of aggregate. The material storage capacity of the batching plant is 1.25 – 2.5 times of the rated production capacity of the mixing equipment, and the conveying belt conveyor is used for feeding in time to ensure the continuous normal work of the concrete mixing plant; Accurate metering ingredients to achieve the reasonable gradation of aggregate, to ensure the comprehensive performance of concrete requirements.

Batching plant maintenance point
1, check whether the vibration motor bolt is loose;
2, bin screen whether there is a jam;
3, check the door limit device is loose, so as not to affect the accuracy of the fall value;
4, check whether the cylinder open is normal and reliable cylinder bolt is loose;
5, check whether the electromagnetic valve action is sensitive;
6, muffler is blocked.

The purpose of concrete mixing maintenance

1, prolong the service life of concrete mixer;
2, ensure the efficient operation of the concrete mixer;
3, reduce downtime, avoid affecting production;
4, indirectly saving the use cost of the company;
5, to create a comfortable working environment;

Know the importance of cement concrete mixing equipment maintenance, we should pay attention to it. According to the survey, mechanical equipment failure rate, 60 % of mechanical equipment failure is caused by poor lubrication, 30 % of mechanical equipment failure is not caused by fastening. Therefore, according to the reason to find a solution to suit the remedy to the case.
Before that, we need to have a knowledge of the mixing building main building structure, in order to carry out subsequent maintenance work, mixing building main building structure: the main building structure from bottom to top can be divided into driving layer, mixing layer, metering layer, sand temporary layer, etc.
The traveling crane layer is mainly used to support the steel structure of the mixing building in order to facilitate the concrete mixing vehicle to pass through. The stirring layer is internally provided with a stirring host machine, which mainly completes various stirring operations. Measuring layer with aggregate hopper, cement measuring bucket, fly ash measuring bucket, water measuring bucket, admixture measuring bucket, etc., mainly to complete all kinds of measuring temporary work. Sand temporary storage layer for mixing the top of the main building, mainly has the material distribution system and other parts

Inclined belt conveyor maintenance point

Aggregate conveying belt conveyor is a kind of conveying equipment with large conveying capacity, low operating cost and continuous conveying. Suitable for conveying loose density 500 ~ 2500 kg / m3 of common bulk materials, working environment temperature is – 10 ℃ ~ 40 ℃, for the aggregate conveyor working in special environment, such as heat, cold, corrosion and other conditions, should take corresponding protective measures.
1, check whether there is any card belt roller / don’t turn phenomenon;
2, check whether the belt running deviation;
3, check whether each component bolt loose;
4, check whether there is sound reducer, have no oil leakage phenomenon;
5, check whether the triangle belt skid, loose;
6, check whether there is loose tension bolt;
7. belt pull switch: in case of emergency, pull down the switch to stop the belt, press the blue button to reset, and regularly check the reliability of the pull switch ( 300 working hours to check the project ).

Follow – up we continue to popularize cement concrete mixing equipment in other equipment maintenance knowledge, please continue to pay attention to our website!

Objective cleaning method of concrete mixer

A lot of users in the use of concrete mixer, after use, concrete mixer cleaning into a headache for users, so the following Camelway machinery manufacturing co., ltd. is simple to introduce how to quickly clean the concrete mixer.
1. stop with a sledgehammer blow method to eradicate the concrete product exists in the concrete mixer cylinder, can only be eradicated with a chisel; The service life of the whole concrete mixer can be ensured and the concrete mixer can be quickly eradicated by using a chisel at the stress point.
2. the concrete mixer after the strike water and stones into the mixing drum 10 ~ 15 minutes to clean, then water and stones out. Pay attention to cleaning, to remove the power supply.
3. cleaning should be carried out regularly, regularly to protect the rules of the project protection, protection work, such as cleaning, lubrication, refueling, etc.
The above three points are relatively objective cleaning methods, customers in need can be combined with the actual situation to deal with.

Analysis of various types of concrete mixer

According to the nature of the work is divided into intermittent ( batch ) and continuous;
According to the mixing principle is divided into self-falling type and forced type;
According to the installation method is divided into fixed and mobile;
According to the discharging mode, the tipping type and the non – tipping type are divided;
According to the mixing drum structure form is divided into pear type, drum type, biconical, disc vertical shaft type and circular groove horizontal shaft type, etc.
1,   according to the nature of the work points:
( 1 ) periodic work mixer; ( 2 ) continuous work mixer.
2,   according to the principle of mixing points:
( 1 ) self – falling mixer; ( 2 ) forced mixer.
3,   according to the shape of mixing barrel points:
( 1 ) drum type; ( 2 ) cone type; ( 3 ) disc.

In addition, the mixer is divided into split drum type and circular groove type ( i.e., horizontal shaft type ) mixer.

Camelway company is specialized in the production of large and medium-sized construction machinery manufacturers, adhere to the ” sincere cooperation, benefit sharing, sustainable management” business philosophy, the main products are wcd series stable soil mixing station, hzs series concrete mixing station,  JS series concrete mixer PLD series concrete dosing machine, hjc concrete truck, cement silo, spiral pump, etc., has been developed to more than a dozen series dozens of varieties, widely used in high-rise buildings, water conservancy, hydropower, highways, bridges construction projects, is the ideal product of high quality of large and medium-sized construction projects.

JS concrete mixer debugging points

A concrete mixer is a shaft with a blade rotating in a cylinder or a tank, mixing and stirring various raw materials to make it a mixture or a machine suitable for consistency. There are many kinds of mixers, including forced mixers, single-shaft mixers, twin-shaft mixers, and so on. In the commissioning of the mixer, what should be noted, we made the following summary of the JS series mixers that were built for strong construction machinery:
1. to check the gearbox and lubrication parts are adequate and good.
2. Check the power supply voltage: The rated voltage is 380 volts and the error is 10%.
3.check the wiring of the motor and electrical components is secure, the distribution box enclosure must be reliably grounded. The zero line of the power supply must be delivered to the terminal block N in the distribution box. All lines should be properly placed to prevent accidents caused by crushing during operation.
4. start the stirring motor, two half shaft rotation direction should be consistent with the direction indicated by the sign, such as the wrong direction, should change the power wiring.
5. start the rolling field motor to enhance the hopper, hopper lift to the discharge position, it should automatically stop, the bucket door automatically open. When the hopper is in motion, if the motor is de-energized, the brake motor will brake the hopper. If the hopper falls more than 50mm, the braking torque is too small, and the large nut of the brake motor should be adjusted to increase the braking torque.When the hopper descends, it jams in the horizontal ramp and descends to the bottom of the pit. The rope is slightly loose, and the lowering stroke switch acts, and the spooling mechanism stops automatically.
6. start the discharge mechanism, opening and closing the discharge door should be accurately in place. Start the pump to pump water and the water supply system should operate normally.
7. Determine the water supply according to the required mix ratio and adjust the time relay to the corresponding water supply time. Start the stirring motor operation.
8. Close the discharge door, add the required mixture to the hopper, and lift the hopper to run smoothly and freely at any position on the track. If there is a slip phenomenon, it should be put into the pit first, and then adjust the big nut on the brake motor.
After the hopper is raised normally and the brake is reliable, the material is fed into the mixing drum and the water pump is started to supply water to the mixing drum.
9. After 25-35 seconds of stirring, start the discharge gate to discharge.
10. In the above-mentioned test operations, if abnormal conditions are found, the machine should be shut down immediately for inspection, troubleshooting, and then test again until it becomes normal. After the new machine is in operation, the bolts on the lining plate and other places shall be handled, and all the nuts shall be checked and tightened. Lubrication part of the transmission lubrication.

Mixing plant manufacturers for the sake of customers is the way to success

High quality engineering concrete mixing station to produce good concrete, it is necessary to strictly control the composition of raw materials. Engineering concrete mixing plant raw materials are generally divided into: cement, coarse and fine aggregate, water, admixture and other materials, mixing plant raw materials quality directly affects the quality of concrete, strict screening of materials and into the factory inspection is very important. Rate of unqualified raw materials shall not enter the mixing plant site.
Cement for engineering concrete mixing plant: the mixing plant shall be a cement manufacturer with quality assurance and good reputation based on local large rotary cellar cement. And replenish ONR’s stock to strictly control the cement three certificate is complete, and in accordance with the provisions of the specification, according to the approval of concrete setting time, stability and strength and other indicators, to ensure the quality of cement. Coarse and fine aggregate: the concrete is mixed with high-quality sand and gravel, and the sand grain size input adopts super-large grain size to improve the strength of the concrete, the unit price of the sand and gravel is improved, but the strength and strength guarantee rate of the coagulation are greatly improved. Therefore, under the condition of the same strength and strength guarantee rate, can reduce the dosage of cement and admixture components, the cost of concrete mixture material is often lower than the use of inferior sand and gravel materials. Water: drinking water is generally used for mixing concrete. if non-drinking water source is used, it shall be inspected in advance or periodically for compliance with regulations. If meet the standard, can also be determined by concrete test whether can be used. Admixtures: mineral admixtures are: ground fly ash, ground slag, ground zeolite and silica fume and their composites. In order to ensure the effective content of mixing plant admixture, should strengthen the inspection of liquid admixture concentration.

Qualified concrete not only needs high-quality engineering concrete mixing plant equipment, more need to cooperate with standard raw materials, in order to be perfect. Camelway machinery industry everything for the sake of customers, our equipment and technology is your success.

How to solve oil leakage in concrete mixing plant?

In the process of stopping consumption of concrete mixing plant, the oil leakage of equipment is a common phenomenon. Concrete mixing plant suitable for different project requirements. This is an economic investment, and the decision whether to buy it makes financial awareness largely dependent on financial rewards. Common professional knowledge, technical advice, help customers make choices.
Concrete mixing plant, because it is very bad working environment, easy to make the vehicle seal ring damage, cause the main reason of oil leakage. Today, professional technicians give some advice to avoid oil spills.
About the impact of concrete mixing station oil leakage, in the welding pad. Sealing and leakage prevention between automotive static parts such as joint surfaces, end caps, housings, cover pads, flat enamel covers, etc. If it does not fit the data and quality skills, it does not play a leak-proof sealing role. Such as oil pan or valve caps, are not easily harden, which can cause oil leakage due to that area.
Seal trouble change in time. Many reset local vehicles ( e.g. oil seals, o – rings ) can differ due to incorrect equipment, axle and oil seal lip and tilt. Some seals may lose elasticity over a long period of time due to rubber aging. If discover concrete mixing truck leak should be updated in time. Seal trouble change in time. Many reset local vehicles ( e.g. oil seals, o – rings ) can differ due to incorrect equipment, axle and oil seal lip and tilt. Some seals may lose elasticity over a long period of time due to rubber aging. If discover concrete mixing truck leak should be updated in time.
The oil leakage of the concrete mixing station may appear in each equipment, so, this requires the staff of the concrete mixing station in the concrete mixing station to stop the maintenance of each system may appear oil leakage parts stop timely maintenance or change, so as to better ensure the concrete mixing station oil leakage situation of the number of times to reduce.