Key Role of Power Trowel in the Finishing Stage of Superflat Floor Construction

WS740 concrete laser leveling machine: the apparatus guide by laser for concrete leveling. Laser leveling leveling machine could greatly improve the concrete smoothness and compaction. as well as prolong the service life of concrete floor. Walk-behind two wheels concrete laser leveling machine, mainly used in large area concrete construction, such as workshop, supermarket, warehouse, airport, playground and so on. This laser leveling can satisfy the construction requirement of large area and high flatness and levelness. As for laser leveling: A new concrete construction,while construct a large area of concrete floor,use laser leveling machine to vibrate new concrete,leveling and control the standard elevation from ground. Technical Description:First,set a fixed laser transmitter,the transmitter emits a laser beam rotation forming a laser control plane,using handheld receivers lever floor elevation guide to the leveling head of Tank concrete laser leveling machine,the automatic control system of leveling machine receiver laser signal (10 times/sec frequency) based on the laser leveling head sensed,then adjust the elevation automatic in real-time,because the laser emitter after the set is fixed,so it can make sure does not produce a cumulative error while a large area of ground construction.  

[MANUAL PK EQUIPMENT] WHAT'S SO GOOD ABOUT VANSE LASER LEVELING MACHINE? We have all seen the exquisiteness of manual production, but after all, it is aimed at a small number of people and cannot be mass-produced, and manual work will prolong the construction time. Some time ago, VANSE Machinery specially conducted a man-machine battle, asking 8 senior technicians to compete with the laser leveling machine, and the result is self-evident. Concrete laser leveling machine has many advantages compared with traditional construction. Take the YZ30-4E concrete laser leveling machine as an example. After years of research and development, Shandong VANSE Machinery is the first to launch a laser leveling machine in China, which directly solves these troubles of customers . Let me tell you about the five advantages of our concrete laser leveling machine compared with traditional construction: About 8 workers use Wanshi laser leveling machine to form a construction team, which can complete 300 square meters of paving work per hour, and a single shift can complete 3000-5000 square meters. In large-area floor construction, manual construction with traditional techniques requires a team of about 15 people, and the workload of a single shift is within 700 square meters. The original labor needs to pay the formwork in advance, which wastes labor, delays the construction period, and cannot effectively return funds. Using VANSE concrete laser leveling machine, 3000-5000 square meters can be completed in one day. The original artificial formwork is supported in advance, the construction effect is low, and the construction period is prolonged. The working principle of VANSE Concrete Laser Leveling Machine is that the laser transmitter generates rotating laser, the laser receiver on the leveling machine receives the signal, and the laser measurement and control system analyzes it, and the deviation will be fed back to the sensitive computer control system on the leveling machine. The left and right electric push rods will adjust the height of the scraper to ensure leveling accuracy and high leveling. The technological principle of VANSE Concrete Laser Leveling Machine is to rely on gasoline generators to generate electricity, and use electric power to drive the laser measurement and control system, computer control system and servo drive system to use the leveling head to complete the leveling work. Laser leveling machine leveling does not need to pull the control line, and also There is no need for side templates to control the ground elevation, but it is controlled in real time by the laser measurement and control system on the leveling machine. As long as the laser transmitter is not disturbed, no matter where the leveling machine moves, the overall elevation of the paved ground can be ensured Not affected.   Our VANSE laser leveling machine uses a high-frequency vibrator of 4,000 times per minute. The uniform high-frequency vibration of the vibrating plate of the leveling head makes the concrete floor dense and can avoid ground cracks caused by stress concentration caused by deformation. It can reduce cracks and effectively solve the problems of hollowing, shelling, cracking and inequality on the ground.

    The occurrence of surface defects in concrete is often not caused by a single factor, but rather the result of the combined effects of materials, the environment, construction techniques and equipment operation. As the final key process in floor forming, the operation mode of the power trowel machine directly affects the final quality of the surface. The following is a detailed analysis of the causes of common surface defects, with a focus on elaborating their correlation with the operation of the power trowel machine. The function of the power trowel machine is to compact, lift the slurry and smooth the surface of the concrete through the high-speed rotating power trowel. Improper operation can directly lead to or exacerbate the following problems: Disrupt the uniformity of concrete (such as bleeding and segregation). Change the water-cement ratio on the surface layer (such as by sprinkling water and grinding). Introduce inappropriate stress (premature heavy-load operation leads to cracking). It is impossible to effectively make up for the deficiencies of the previous processes. Defect description: Insufficient surface strength, loose cement and fine sand shedding. The fundamental cause The water-cement ratio on the surface is too high (bleeding or excessive watering). The cement grade is insufficient or the quality is poor. Improper maintenance causes the surface to lose water too quickly. The correlation with the operation of the power trowel machine (main reason) : Premature operation: Start smoothing the concrete when there is still a large amount of bleeding, removing the cement slurry and leaving only the sand. Excessive water sprinkling on flour grinding: This is the most fatal operation. When the surface is dry, workers sprinkle water to save effort, which greatly increases the water-cement ratio of the surface layer and seriously reduces the surface strength. The timing of power trowel is too late: The concrete has already begun to set, and the power trowel cannot effectively lift and compact the slurry. It merely "scraped" once and failed to bring the cement slurry to the surface. Improper blade Angle or severe wear: Unable to effectively compact the surface layer. Defect description: Irregular, shallow and fine reticular cracks appear on the surface. The fundamental cause The evaporation rate of surface moisture is greater than the bleeding rate (in high-temperature, windy, and low-humidity environments). Concrete itself has poor bleeding. Correlation with the operation of the power trowel machine: Failure to seal the surface in time: The first (bottom grinding) process of the power trowel is of vital importance. That is, under the aforementioned environmental conditions, when the concrete can reach the person mentioned above (about 25-30mm deep footprint), the power trowel should be used in conjunction with the disc to lift the slurry and seal it in time to prevent the water from evaporating too quickly. If the waiting time is too long and the crack has already formed, it will be of no avail to smooth it out. Improper operation aggravates water loss: The high-speed rotating power trowel generates heat by rubbing against the concrete and accelerates water evaporation under the influence of air flow. In harsh environments, attention should be paid to operational efficiency. After completing a certain area, timely maintenance should be carried out. Defect description: The ground is overall uneven, with a "ladle" or "wavy" feeling. The fundamental cause The initial flatness control of the laser screed is not good. The slump of the concrete is uneven. The correlation with the operation of the power trowel machine (main reason) : The operation method is not professional Without adopting the "horizontal and vertical cross" method: Always grinding in the same direction, it is easy to form a "furrow" effect, resulting in strip-shaped protrusions. If the machine body stays in one position for too long, the weight of the power trowel and vibration will cause that area to slightly sink, forming a "dent". Improper timing of raising or lowering the arm: When changing direction, failing to lift or lower the power trowel plate/power trowel smoothly can result in knife marks or local protrusions. Uneven walking speed: The inconsistent speed leads to different degrees of compaction, resulting in color differences and slight height differences. Defect description: The ground color varies in depth. The fundamental cause The raw materials (especially cement) vary from batch to batch. The pouring interval is too long, resulting in cold joints. Correlation with the operation of the power trowel machine: The timing of the finishing is not accurately grasped: There are slight differences in the initial setting time of concrete in different areas. If the operator stops the light in some areas when it is still bleeding (the color is bright), while in others when it is close to final setting (the color is dark), a color difference will occur. Repeatedly grinding the same area: Repeatedly grinding a relatively wet local area will result in excessive slurry in that area and a color that is different from other areas. Uneven watering: If water is sprinkled locally to grind the surface, it will directly cause the water-cement ratio in that area to be different, resulting in a lighter and whiter color. Defect description: The surface-hardened layer has detached from the lower layer. The fundamental cause The surface is over-polished, forming a dense but fragile cement paste layer, which is inconsistent with the contraction of the lower layer. The lower layer of concrete has severe bleeding, forming a water film and weakening the interlayer bonding force. The correlation with the operation of the power trowel machine (key reason) : Excessive finishing: Forcing the use of a power trowel machine after the concrete has r To avoid the above-mentioned defects, the operation of the power trowel machine should follow the principle of "timely and moderate". Operation stage Key points for correct operation Purpose and avoidable defects Initial grinding (pulp extraction Timing: When the foot sinks by about 3 to 5mm. Objective: To remove the slurry on the surface of the aggregate and seal the surface. Tool: Install the disc. Avoid: Cracking and sanding. Technique: Move at a constant speed and cover the entire area. Smooth (finely grind Timing: After initial grinding, the surface is free of moisture and has a matte color. Objective: To eliminate scratches, fine deviations and further compact. Tool: Replace with a fine power trowel (power trowel). Avoid: poor waviness and color difference. Technique: Use the horizontal and vertical intersection method, maintain a uniform speed, and lift the arm to press down steadily. Fine grinding (finishing) Timing: After smoothing, there is almost no trace left when stepped on (close to final setting). Objective: To obtain a dense and smooth surface. Tool: The same or thinner spatula, adjusted to a small Angle. Avoid: hollowing, color difference, and cracks caused by excessive dimming. Technique: Gentle and steady, succeed in one go, avoid repetition. The Golden Rule 1. No sprinkling water! If the surface does lose water prematurely, a very small amount of water should be sprayed with a sprayer, and this should be done before the initial grinding. Eliminate most surface defects fundamentally. 2. Timing is the key! Closely observe the setting state of the concrete rather than the rigid time. 3. "Intersection" and "uniformity" are at the core of flatness. An excellent power trowel operator is not only a machine operator but also an "observer" and "manager" of the concrete setting process. He needs to understand the fundamental principles of materials science, and through precise operation timing and proficient techniques, transform the solid foundation created by the laser screed into a high-quality floor with high strength, high flatness and no defects.   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.