Technical Knowledge
What are the differences in construction technology between concrete pavements with large slump and concrete pavements with small slump?
There are many differences in the construction process between concrete pavement with large slump and concrete pavement with small slump, as follows
Mixing
Concrete with large slump: The mixing time needs to be appropriately increased, generally 30-60 seconds longer than concrete with small slump, to ensure that the concrete is mixed evenly, so that the excess water is fully mixed with cement and other materials to avoid segregation. At the same time, the amount of water should be strictly controlled and accurately measured, because the amount of water has a greater impact on the slump.
Concrete with small slump: When mixing, pay attention to controlling the mixing force and time to avoid excessive mixing that causes the concrete to be too dry and hard, and lose good workability. Generally, the mixing time is relatively short, so that all materials can be evenly mixed.
Transportation
Concrete with large slump: Prevent concrete from segregation and water evaporation during transportation. The mixer truck should maintain a uniform speed, avoid sudden braking and sharp turns, and reduce the shaking of the concrete in the tank. At the same time, the tank body can be covered with a sunshade to prevent direct sunlight from causing water to evaporate too quickly and affect the slump.
Concrete with small slump: During transportation, care should be taken to prevent excessive loss of concrete slump. If the transportation time is long, some plastic preservation measures can be considered, such as adding an appropriate amount of retarder. However, attention should be paid to the amount of retarder added to avoid affecting the setting time and strength of the concrete.
Pouring
Concrete with large slump: The pouring speed should not be too fast and should be controlled within a certain range, such as the pouring volume per minute should not exceed 1-1.5 cubic meters to avoid rapid flow and accumulation of concrete in the formwork, resulting in loose vibration or segregation. At the same time, it is necessary to avoid excessive free fall height of concrete. When it exceeds 2m, auxiliary tools such as string barrels and chutes need to be used.
Concrete with small slump: Due to its poor fluidity, some auxiliary measures are needed during pouring to ensure that the concrete can fill every corner of the formwork. For example, artificial auxiliary spreading can be used to evenly distribute the concrete in the formwork to avoid concrete accumulation or local vacancies.
Vibration
Concrete with large slump:
It is advisable to use a low-frequency vibrator, and the vibration frequency is generally 2000-3000 times/minute. Avoid using a high-frequency vibrator to cause over-vibration of the concrete. The vibration time should not be too long. The vibration time at each point should be controlled within 20-30 seconds, and the concrete surface no longer sinks significantly, no bubbles appear, and cement slurry appears on the surface.
Concrete with small slump:
It is usually necessary to use a high-frequency vibrator, and the vibration frequency is generally 3000-5000 times/minute to improve the fluidity and density of the concrete. The vibration time should be appropriately extended, and the vibration time at each point may take 30-40 seconds to ensure that the concrete is vibrated and dense, but it is also necessary to prevent excessive slurry on the concrete surface due to over-vibration.
Surface finishing and maintenance
Concrete with large slump: When finishing, wait for the surface moisture to evaporate properly before proceeding, generally 1-2 hours after the concrete pouring is completed. The specific time is determined according to the site environment and the concrete coagulation. Usually 2-3 times of plastering are required to eliminate moisture and defects on the surface. Plastic film, geotextile, etc. should be used to cover the surface immediately during curing to prevent the water from evaporating too quickly and causing the surface to lose water and crack. The curing time is generally not less than 14 days.
Concrete with small slump: Plastering can be done in time after the concrete surface is slightly dry, generally about 0.5-1 hour after pouring. Due to its low moisture content and fast surface drying, fewer plastering times may be required, but attention should be paid to the plastering quality to ensure that the surface is flat and smooth. It should also be covered and moisturized in time during curing. The curing time is generally not less than 7 days, but if the environment is dry or the temperature is high, the curing time should be appropriately extended.
Thanks to All the Friends Who Support and Trust Shandong Vanse Machinery Technology Co., Ltd.
If you want to know more about Shandong Vanse Machinery Technology Co., Ltd. or have any questions, please feel free to contact us:
Our Factory
Shandong Vanse Machinery Technology Co., Ltd.
Share this article
About the Author: Shandong Vanse Machinery Technology Co., Ltd.
Shandong Vanse Machinery Technology Co., Ltd. is a high-tech manufacturer specializing in concrete construction machinery, including laser screeds and related equipment. The company integrates R&D, production, and global sales, with products exported to over 60 countries and widely used in infrastructure projects worldwide.
Previous Post
Next Post
Related Articles
You Might Also Like
What is the working principle of concrete laser leveling machine?
The concrete laser leveling machine is an advanced equipment that uses laser technology for ground leveling. Its working principle mainly includes the following aspects: 1. Laser transmitting and receiving: The leveling machine is equipped with a laser transmitter, which emits a precise laser beam. At the same time, a laser receiver is installed on the leveling head of the leveling machine to receive and process these laser signals. 2. Real-time adjustment and control: The laser receiver will process the received laser signals in real time and perform precise adjustment and control based on these signals. The leveling head will automatically adjust its height and position according to the guidance of the laser signal to ensure the accuracy of the leveling process. 3. Movement and leveling work of the leveling head: The leveling head moves under the drive of the leveling machine. It is equipped with scrapers, spirals, vibrating plates and other components. During the leveling process, these components work together to complete the initial leveling, vibrating and leveling of the concrete. 4. Computer control system: The leveling machine is equipped with a computer control system for monitoring and controlling the entire leveling process. This system can adjust leveling parameters such as leveling speed, vibration frequency, etc. as needed to ensure the optimization of the leveling effect. 5. Control of floor elevation: A significant feature of the laser leveling is that it can break away from the traditional mode of controlling the floor elevation by construction templates. Through the laser control system, the leveling machine can accurately control the elevation of the floor, greatly reducing manual errors and improving construction speed and accuracy. To sum up, the working principle of the concrete laser leveling machine is mainly to achieve precise leveling of the ground through laser technology. It uses laser transmitters and receivers for precise measurement and control. Through the movement and leveling work of the leveling head, combined with the monitoring and adjustment of the computer control system, it achieves efficient and precise leveling of the concrete floor. This technology has greatly improved construction efficiency and quality, and has become one of the important equipment in modern floor construction.Maintenance knowledge of concrete laser leveling machine
Concrete laser leveling machine is a high-precision construction equipment used to achieve high flatness and high precision requirements on concrete surfaces. In order to ensure the long-term use and reliability of the concrete laser leveling, regular inspection and maintenance are necessary. The following is an introduction to the maintenance knowledge of concrete laser leveling machines, including the necessity of regular inspection and maintenance. 1. The necessity of regular inspections 1) Failure prevention: Regular inspections can detect potential problems or failures in time and avoid equipment downtime or major failures during the production process. Through regular inspections, problems can be repaired before they occur, ensuring the stable operation of the equipment. 2) Ensure safety: The concrete laser leveling is a heavy-duty equipment with potential safety risks. Regular inspections can ensure that the equipment's safety devices and protective devices are working properly and prevent accidents. 3) Optimize performance: Regular inspections can ensure that each component of the concrete laser leveling is in good working condition and improve the overall performance of the equipment. This includes inspections and adjustments to transmission systems, hydraulic systems, electrical systems, and more. 4) Extend life: Regular inspections can detect and repair potential wear or damage in time to avoid larger problems during the operation of the equipment. This helps extend the life of the concrete laser leveling and reduces replacement costs. 2. The necessity of regular maintenance 1) Cleaning and Cleaning: Regularly cleaning the surface and internal parts of the concrete laser leveling can remove dust, dirt and other impurities. This helps improve the cooling performance of the device and reduces the risk of failure. 2) Check the hydraulic system: The hydraulic system is an important part of the concrete laser leveling machine. Regularly check various components of the hydraulic system, including oil tanks, oil pumps, hydraulic cylinders, etc., to ensure that there are no leaks, no abnormal sounds, and no abnormal vibrations. 3) Check the electrical system: The electrical system is an important control system for the concrete laser leveling machine. Regularly check all components of the electrical system, including cables, plugs, terminals, etc., to ensure that they are not damaged, loose, or abnormally hot. 4) Check the transmission system: The transmission system is an important power transmission system for the concrete laser leveling. Regularly check various components of the transmission system, including gears, chains, bearings, etc., to ensure that there is no abnormal noise, abnormal vibration, or excessive wear. 5) Lubrication: Regularly adding appropriate lubricants to each lubrication point of the concrete laser leveling can reduce the friction and wear of the equipment and improve the operating efficiency and service life of the equipment. 6) Check the hydraulic oil: Hydraulic oil is an important part of the hydraulic system of the concrete laser leveling machine. Regularly check the quality and quantity of hydraulic oil to ensure it meets requirements. If the hydraulic oil deteriorates or is insufficient, it should be replaced or added in time. 7) Check the coolant: The concrete laser leveling machine will generate a lot of heat during operation. Regularly check the quality and quantity of coolant to ensure it meets requirements. If the coolant is insufficient or deteriorates, it should be replaced or added in time. In short, in order to ensure the long-term use and reliability of the concrete laser leveling, regular inspection and maintenance are necessary. Through regular inspections, potential problems or faults can be discovered in time and corresponding measures can be taken to repair them; through maintenance, the equipment can be kept in good condition and its performance and service life can be improved. It is recommended to formulate an appropriate maintenance plan and perform maintenance work on time under the guidance of the equipment instruction manual or professionals.How to Verify Laser Leveling Effect through F-number (FF/FL) System?
In the high-stakes world of industrial flooring-especially for VNA (Very Narrow Aisle) warehouses and automated logistics hubs-"flat enough" isn't a measurement. To prove your work meets international standards, you need the F-number system (FF/FL). If you're using a Concrete Laser Leveling Machine and need to verify your results for a client, here is the professional's guide to understanding, measuring, and hitting those high scores. Before you pull out the testing equipment, you need to know what the numbers represent. Global buyers and engineers follow the ACI 117 standard, which breaks down into two parts: FF (Floor Flatness): This measures the "waviness" of the surface. Think of it as the small bumps and dips. High FF numbers mean a smoother ride for forklifts. FL (Floor Levelness): This measures the overall tilt or slope of the slab. It's about how close the floor is to the actual horizontal plane. Timing is everything. To get an accurate reading that reflects the machine's performance, measurements should be taken within 24 to 72 hours after placement. If you wait too long, concrete curling (due to drying) can throw off your FL numbers, even if your laser leveling did a perfect job. You can't verify a high F-number if the machine didn't produce it in the first place. This is where the engineering of your Concrete Laser Leveling Machine comes into play. Vanse Insight: To achieve FF numbers in the 50s or 60s (Superflat), the machine's hydraulic response must be instantaneous. Vanse's YZ series, uses high-speed laser receivers that talk to the leveling head 10 times per second. This constant, automatic correction is what eliminates the "waves" that tank your FF scores. Most international contractors use an F-Meter or a Dipstick® Profiler. Walk the Lines: You don't measure the whole floor randomly. You walk the device in straight lines across the slab. Data Collection: The device records the elevation changes every 12 inches (30cm). The Result: The software calculates a statistical average. If your goal was FF 50 and you hit FF 52, you've verified that your laser leveling machine and your crew executed the plan perfectly. When a buyer asks, "Can your machine hit FM1 standards?" they are asking about reliability. Here's how Vanse Machinery ( www.vansemac.com ) supports those high-spec requirements: Integrated Vibration: A major enemy of FF numbers is uneven concrete density. Vanse machines feature high-frequency vibration integrated directly into the leveling head, ensuring the slab is consolidated uniformly before the final pass. Telescopic Precision: For the highest FL accuracy, the Vanse YZ30-4E telescopic boom allows the machine to stay in one spot while the head extends. This removes the variable of machine weight shifting on the wet concrete, which is a common cause of "dips" in the F-number report. Dual-System Control: By combining top-tier laser transmitters (Leica/Trimble) with Vanse's proprietary hydraulic control, the margin for error is reduced to nearly zero. Note: The parameters provided in this document are for reference only and are not mandatory. Due to differences in technical characteristics between different brands and models of laser levelers, please consult the manufacturer for a suitable solution before actual operation. This reference document assumes no responsibility for any issues arising from failure to follow the manufacturer's instructions.
