Technical Knowledge
Requirements & treatment for laser leveling of concrete base layers before grinding of special floors (such as epoxy floors and curing agent floors)
The quality of the concrete base directly determines the final effect and service life of special floors (such as epoxy and curing agent floors). Laser leveling, as a high-standard process in modern floor construction, lays a solid foundation for subsequent grinding and surface layer construction.
The following is a detailed description of the requirements and treatment for laser leveling of concrete base before grinding of special floors:
Ⅰ. Core Objective: To provide an ideal "canvas" for grinding and surface layer construction
The concrete base layer after laser leveling and treatment should achieve the following core goals to meet the requirements of special floors
Extremely high flatness: Eliminate large areas of waves and local height differences, ensure uniform thickness of the floor surface layer, and avoid problems such as uneven coating wear and dust accumulation caused by uneven base surfaces.
Excellent levelness: Ensures that the ground meets the designed elevation, especially for large factories, warehouses and other places with strict requirements for ground slope.
Solid surface strength: The base concrete must have sufficient compressive strength and surface hardness to prevent sanding, hollowing, and be able to withstand grinding by a grinding machine.
Dense and uniform surface: Reduce pores, prevent excessive penetration of floor materials (such as epoxy primer), and provide uniform adhesion for the surface layer at the same time.
Controllable cracks: Through reasonable cutting techniques, irregular cracks are guided to the preset shrinkage joints to ensure that no random cracks occur on the surface layer.
Ⅱ. Specific Requirements for the Laser Leveling Stage
Laser leveling is the crucial first step to achieving the above goals.
1. Base (subgrade) treatment
Compaction degree: The soil base must be fully compacted, with a density of no less than 90%, to prevent concrete cracking caused by future settlement.
Cushion layer: Usually, graded crushed stone is used as the cushion layer, with a thickness of no less than 150mm. It needs to be evenly spread and compacted. The cushion layer serves as the foundation for stress dispersion and drainage.
Waterproof and moisture-proof: For floors with a high groundwater level or the first floor, a moisture-proof layer (such as PE film) must be set up to prevent the rise of underground water vapor from causing the epoxy floor to bubble and peel off.
2. Requirements for concrete materials
Strength: The grade should not be lower than C25. For areas with heavy load requirements, it is recommended to use C30 or higher. The compressive strength should ultimately reach above 25MPa.
Mix ratio: The water-cement ratio is crucial and should be strictly controlled below 0.5. A low water-cement ratio is the prerequisite for ensuring the high strength and wear resistance of concrete.
Aggregate: Medium and coarse sand and continuously graded crushed stone should be used, with the maximum particle size not exceeding 25mm, to ensure the compactness of the concrete.
Additives: Water-reducing agents (ensuring workability while reducing the water-cement ratio), fibers (anti-cracking), etc. can be added as needed.
3. Requirements for laser leveling construction technology
Set control points: Based on the designed elevation, establish an accurate horizontal control network through a laser emitter.
Concrete paving: The height of the loose paving should be 2-3cm higher than the designed elevation to prepare for the compaction and leveling by the leveling head.
Concrete laser leveling machine operation
The concrete laser leveling relies on laser signals to automatically control the height of the scraper, precisely spreading and initially compacting the concrete.
Advantages: Compared with traditional techniques, it can achieve extremely high flatness (the height difference within a 2-meter straightedge is ≤3mm) and levelness, with extremely high efficiency and reduced reliance on workers.
Synchronous processing: After laser leveling, a large trowel with a diameter of more than 1 meter should be used immediately to lift the slurry and finish the surface, flattening the surface floating slurry and aggregates to prepare for subsequent processing.
Ⅲ. Key Processing Procedures after Leveling (Before Grinding)
Laser leveling merely creates a "rough blank". To meet the standard of a base layer that can be ground, a series of fine treatments are still required.
1. Finishing and smoothing
Timing control: The mechanical trowel operation should be carried out after the initial setting of the concrete and before the final setting (when the depth of the footprints left by a person standing on it is approximately 2-3mm).
The process is usually carried out in 2 to 3 rounds. For the first coat, use a disc to lift the slurry and smooth it out. Subsequently, switch to different trowelers for cross-operation to smooth and polish the surface. High-quality polishing is the core for achieving a hard, dense and uniform surface.
2. Maintenance
Objective: To ensure the full hydration of cement, enhance its strength and prevent cracking.
Method
Recommendation: Spray the special concrete curing agent to form a sealing film.
Traditionally effective: Cover with plastic film or lay non-woven fabric and sprinkle water to keep it moist.
Time: At least 7 days. During this period, no load is allowed.
3. Cutting (shrinking)
Objective: To guide the release of concrete shrinkage stress at the preset position, form neat straight cracks, and avoid irregular cracking.
Timing: Usually within 6 to 24 hours after pouring (when the strength reaches 5 to 10MPa), it should be able to cut through the concrete without carrying the aggregates.
Requirement
Spacing: Generally 20 to 30 times the thickness of the concrete slab, usually 4 to 6 meters.
Depth: 1/4 to 1/3 of the plate thickness.
Position: Align with the center line of the column and the edge line of the equipment foundation to maintain aesthetics.
4. Base inspection (must be carried out before grinding)
Before planning the grinding construction, a comprehensive assessment of the concrete base must be conducted:
Strength: The compressive strength should be ≥25MPa when tested using a rebound tester or core sampling. Insufficient strength and direct grinding will cause the aggregates to peel off.
Flatness: Use a 2-meter straightedge for inspection. The drop at any point should be ≤3mm. Laser-leveled floors can usually be easily achieved.
Moisture content: Tested using a CM type moisture content tester. For epoxy flooring, the moisture content of the base layer should be ≤4%. For the curing agent floor, the requirements can be appropriately relaxed, but there must be no standing water.
Surface quality: Check for no hollowing (by tapping with a small hammer), no sanding, no cracks (except shrinkage joints), no oil stains or other contaminants.
Ⅳ. Pretreatment of the base layer before grinding
Even after the above processes, some pretreatment may still be required before formal grinding:
Cleaning: Thoroughly remove any residual maintenance agent, dust and debris from the ground.
Repair: To repair minor defects, cracks or hollows in a local area. Use high-strength epoxy resin or special cement-based repair mortar.
Preliminary grinding: If there is a slight amount of floating slurry or hardener residue on the surface, it may be necessary to use a metal grinding disc for a preliminary and light grinding to open up the surface pores and prepare for the subsequent penetration of the curing agent or the adhesion of the epoxy primer.
Summary
For special floors, the saying "seven parts base layer and three parts surface layer" is no exaggeration. Laser leveling technology makes it possible to achieve high-quality concrete base layers, but it must be combined with strict material control, precise timing of construction, perfect curing and scientific joint treatment.
A qualified laser-leveled concrete base layer suitable for grinding should possess:
Level: Check with a 2-meter straightedge. The drop should be no more than 3mm.
Strong: Compressive strength ≥25MPa, with a hard surface and no sanding.
Dry: Moisture content meets the standard (epoxy ≤4%).
Clean: The surface is clean, free from contamination and hollowing.
Uniform: The surface is dense and uniform with small color differences.
Only in this way can the subsequent grinding process be carried out efficiently, and the epoxy or curing agent floor can fully demonstrate its best wear resistance, pressure resistance, aesthetic appeal and long service life.
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.
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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.
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Construction Precautions for Concrete Laser Leveling Machines in Extreme Temperature Environments
In extreme temperature environments (high or low), the performance of concrete laser Leveling machines and the setting state of concrete are significantly affected. Based on professional guidance from Vanse Machinery, the following are key precautions for construction in extreme temperature environments: In high-temperature environments, rapid water loss from the concrete and overheating of the hydraulic system are the biggest challenges. Oil Selection: High viscosity index hydraulic oil (such as No. 68 hydraulic oil) must be used to prevent the oil from thinning and causing insufficient pressure due to high temperatures. Radiator Cleaning: Inspect and clean the cooling fins of the engine and hydraulic system before daily operation to prevent dust and cement slurry from clogging them and affecting heat dissipation. Intermittent Operation: Under extremely high temperatures, avoid continuous operation of the machine under overload; if necessary, take measures to stop the machine and cool it down. High temperatures cause concrete slump to drop extremely quickly. During construction, the travel speed of the laser Leveling should be strictly controlled to ensure leveling is completed before the concrete initially sets. Substrate Moistening: The substrate (base) must be thoroughly moistened before construction to prevent it from absorbing moisture from the concrete, which could lead to shrinkage cracks in the underlying layer. High temperatures can cause ground-level heat waves (heat waves) to refract the laser beam, resulting in a "drift" phenomenon. Solution: Erect the laser transmitter in the highest and coolest possible location, and minimize the distance between the transmitter and receiver (ideally within 30-40 meters) to ensure accuracy. Low temperatures can affect machine start-up performance and the hardening speed of concrete. Low-viscosity oil: Replace with low-temperature special engine oil (such as 5W-40) and low-pour-point hydraulic oil (such as No. 32 aviation hydraulic oil) to prevent oil solidification that could damage the pump head. Start-up preheating: Do not operate at high speed immediately after starting. Allow the machine to idle for 10-15 minutes until the hydraulic oil temperature rises above 20°C before beginning leveling operations. Batteries experience a significant capacity reduction at low temperatures. After construction is completed, the batteries and laser emitter should be removed and stored in a warm indoor environment to prevent power loss or freezing and cracking of the LCD screen. When using a laser Leveling, ensure the concrete temperature upon placement is not lower than 5°C. Post-screing treatment: After the machine completes the screing, immediately cover the concrete with plastic film and insulating straw mats to prevent freezing and subsequent surface sanding or cracking. Laser Accuracy Verification: Drastic temperature changes can cause thermal expansion and contraction of precision components inside the laser emitter. It is recommended to recalibrate the reference level every 2-3 hours of continuous operation. Seal Inspection: Extreme high temperatures accelerate seal aging, while extreme low temperatures make seals brittle. Special attention should be paid to checking all hydraulic cylinder joints for leaks. Personnel Safety: In extreme environments, heatstroke prevention and frostbite protection for construction personnel are equally important. If you are carrying out special flooring construction (such as cold storage floors or outdoor plazas) in extremely cold regions (such as below -10°C) or tropical regions, it is recommended to contact WanShi Machinery's technical support to obtain an oil change list and parameter setting guidance for specific machine models. 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.Which one has higher working efficiency and which one lower between concrete laser leveling machine and paver?
Concrete laser levelings and push paver machines each have their own advantages in terms of work efficiency, and it is difficult to directly compare which one is higher and which is lower. This is because the usage scenarios and working principles of the two devices are different, resulting in their performance in work efficiency being different. The concrete laser leveling machine is mainly used for floor leveling work. It uses laser technology for positioning and can quickly and accurately complete the floor leveling work. Due to its high precision and efficiency, the concrete laser leveler performs well in leveling work on large floors, squares, warehouses and other places. In addition, the concrete laser leveling machine can also be equipped with different working devices to adapt to different construction needs, further improving its work efficiency. Paver machines are mainly used for paving infrastructure such as roads and bridges. Pavers can quickly lay and level a variety of materials, such as asphalt, cement, and more. Its working principle is to transport materials to the working position through a conveyor belt and use a leveling to level them. Because pavers are suitable for large-area, continuous paving work, they have high work efficiency in the construction of infrastructure such as roads and bridges. In summary, concrete laser levelings and push paver machines each have their own advantages in work efficiency, depending on the usage scenario and construction needs. When choosing which equipment to use, comprehensive considerations need to be made based on the actual situation to achieve the best construction results and economic benefits.Differentiated considerations for the selection of concrete laser leveling machine in indoor and outdoor projects
There are significant differences in the selection considerations of concrete laser leveling machine for indoor and outdoor projects, mainly due to the differences in engineering environments, concrete properties, technical requirements, and the quality goals of the final products. The following will elaborate on this differentiated consideration in detail from multiple dimensions: Interior engineering: Greater emphasis is placed on precision, efficiency, flexibility and environmental protection. The ground, as the final finish or the foundation for supporting precision equipment, has extremely high requirements for flatness and levelness. Outdoor engineering: More emphasis is placed on equipment power, passability, anti-interference ability and adaptability to the base layer. In the face of harsh environments, large aggregate concrete and complex base conditions, the stability and "brute force" of the equipment are the key. Dimension of consideration Dimension of consideration Interior engineering Outdoor engineering 1. Ground accuracy requirements Extremely high Relatively low The flatness (FF/FL) requirement is high, and it is often necessary to meet the super-flat floor standard (such as FF≥50, FL≥35). Most of them are road surfaces, storage yards, squares, etc., and the requirement for flatness is lower than that for indoor areas. It is used in warehouses, logistics centers, precision manufacturing workshops, etc., directly affecting the operational efficiency of equipment and the stability of shelves. The allowable error range is larger, but it is necessary to ensure that the drainage slope meets the design requirements. 2. Device type preference First choice: Wheeled concrete laser leveling machine First choice: Wheeled (large tire) laser leveling machine • Advantages: Low grounding specific pressure, which will not cause damage to the base layer or the already laid steel mesh. It walks smoothly with low vibration and has the highest leveling accuracy. It turns flexibly and is suitable for areas with complex shapes. • Advantages: Good mobility and fast transfer speed; It has a high ground clearance, strong passability and can adapt to uneven base surfaces. Tires have better tolerance for rough substrates. 3. Grassroots conditions and passability Good conditions The conditions are complex and changeable. The base layer is usually compacted and leveled, with a smooth and solid surface. The base layer may be compacted soil base or crushed stone layer, which may be uneven and soft. There may be obstacles such as columns and walls in the space, which requires the equipment to be mobile and flexible. There may be slopes and potholes, so the equipment is required to have good passability and strong driving force. 4. Concrete properties The slump is small Large slump and large aggregate Most of them are fine aggregate concrete with small aggregate particle size and low slump (dry-hard concrete), which is convenient for laser leveling machines to complete compaction and leveling in one go. Coarse aggregate concrete is often used, and the aggregate particle size is large. The slump may be relatively high, and the requirements for the disturbance and subsidence control capabilities of the leveling are different. 5. Laser system High precision and multi-adaptability Strong anti-interference ability A laser system must be used and the accuracy of the receiver is required to be high. Both laser systems and GPS systems can be used. In multi-storey buildings, the deflection of floor slabs needs to be taken into account. Sometimes, multi-point laser or GPS systems are required to simulate the preset camp. GPS has obvious advantages in large outdoor areas, with no problem of visual obstruction and no need to frequently move base stations. The laser system needs to take into account the influence of strong outdoor light and strong wind on the stability of the laser signal. 6. Power system Mainly electric or electric + hydraulic Mainly high-power diesel engines • Electric: Zero emissions, low noise, highly suitable for construction in confined Spaces, meeting indoor environmental protection requirements. • Diesel engine: It offers powerful traction and vibration power, capable of handling large-aggregate concrete and complex substrates. The power demand is relatively low. The requirements for emissions and noise are relatively lenient. 7. Environmental Protection and Working Environment Demanding The requirements are lenient It must be low-noise and have zero emissions to avoid polluting the indoor air. It has relatively low requirements for noise and emissions. The size of the equipment should take into account the size restrictions of construction elevators and door openings. The working environment is harsh (sun exposure, rain, and dust), which requires the equipment to have a high protection level and a sturdy and durable structure. 8. Construction efficiency and area High efficiency, medium and small area Continuous operation over an extremely large area The daily construction area is large, but the individual operation surface is usually smaller than the outdoor area. It is commonly seen in airports, highways and large squares, with a huge single pouring area. Efficiency is reflected in the rapid leveling with high precision, reducing subsequent manual repairs. Efficiency is reflected in the continuous and uninterrupted large-scale paving and leveling capabilities. Step 1: Clarify the project attributes (indoor/outdoor) If it is an interior project Precision requirement: Does it meet the standard of super-flat floor? Yes -> Give priority to high-precision tracked types. Space limitations: Are there any obstacles such as columns or walls? Is the size of the door opening restricted? Yes -> Choose small-sized or equipment with column anti-blocking function, such as Vanse YZ30-4E Environmental protection requirements: Is it a sealed or clean environment? Yes -> Electric power must be chosen. Concrete type: Is it fine aggregate low slump concrete? Yes -> Suitable for all types of levelings. If it is an outdoor project Area and terrain: Is the area large (> 10,000 square meters) and the terrain open? Yes -> Give priority to wheeled +GPS systems. Base conditions: Is the base soft and uneven? It is -> Choose wheeled equipment with large tires, high ground clearance and strong driving force. Concrete type: Is it aggregate concrete? Yes -> Choose equipment with powerful vibration power. Slope control: Are there any complex requirements for the drainage slope? Yes -> The GPS system has more advantages in three-dimensional slope control (Vanse YZ30-4E/WS940C supports 3D system construction). In conclusion, choosing a concrete laser leveling machine for indoor and outdoor projects is essentially a trade-off between "precision" and "robustness". The core of interior selection is to find a "meticulous artist" who can carve out an extremely smooth floor within a small space in a clean environment. Wheeled, electric/diesel, and high-precision laser are its labels. The core of outdoor selection is to find a "strong warrior" that can overcome wind, rain and rough terrain, and efficiently complete the paving task in the vast expanse of the world. Wheeled and diesel power are its weapons. Correct selection not only ensures construction quality but also greatly enhances construction efficiency, reduces labor costs and safety risks. Therefore, before purchasing or leasing equipment, it is essential to conduct a comprehensive assessment based on the specific characteristics of the project. 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.
