Concrete laser leveling machine winter maintenance tips

Tell you how effective the concrete laser leveling machine is! Many consumers are still hesitating whether they should buy a concrete laser leveling machine, because they have no concept of the construction effect of the equipment. Today we will introduce the use effect of the equipment. First of all, the biggest feature of this equipment is that it is fast, and the time-consuming is 1/10 of manual work, which is enough to make many construction teams excited; secondly, it is flat, and the ground level error after paving is small , is almost negligible. 1. Requirements for concrete and formwork ① Concrete:  Concrete must be produced, conveyed or pumped to the flooring site by a commercial concrete production plant. ② Concrete specifications: C25~C30 concrete, the strength of which is not less than 25MPa in 28 days, according to the design requirements. ③ Water-cement ratio: N o more than 0.5, no water can be added during the feeding process. ④ Cement: Use ordinary Portland cement with a grade of not less than 42.5. ⑤ Aggregate: Well-graded aggregate should be used. Crushed granite or pebbles are used as coarse aggregate, and the maximum diameter is not more than 25mm. The fine aggregate is clean river sand with a fineness modulus of 2.4-2.7. ⑥ Concrete mix ratio: The amount of cement is not less than 350Kg/m3. In order to avoid surface quality problems, the sand rate should be controlled at 35% to 40%. ⑦ Concrete slump: 14±2cm, maximum 16cm. ⑧ Setting time: The initial setting time should be controlled within 3-5 hours. In order to avoid the excessive deviation of the surface elevation affecting the joints, the formwork should be steel formwork. The height of the formwork should be controlled within +0 and -2mm, and the steel formwork should be within 1-1.2 meters from the surrounding walls. 2. Construction cooperation requirements ① The concrete feeding speed should be determined according to the ground thickness and pouring area to determine the minimum hourly feeding speed. For a floor with a thickness of 200 mm, if the width of one-time pouring reaches 40 meters, the minimum feeding speed should reach 40 cubic meters per hour, otherwise there will be cold joint problems, which will affect the quality of ground construction. ② Manually coordinate the concrete sent to the platform, and workers need to remove it as soon as possible and roughly level it. In addition, the areas around the formwork, walls, columns, trenches, equipment foundations, floor drains or around pipelines that cannot be leveled require manual cooperation for local leveling. Generally, 3-4 workers are required to cooperate with the construction (provided by Party A). ③ Other precautions In order to ensure the flatness of the ground, attention should be paid to: 1) The slump of concrete sent to the platform must be consistent each time. 2) Ensure that the concrete feeding speed reaches 40 cubic meters per hour or above, and the initial setting time of each batch of concrete must be consistent. 3) Ensure that the formwork elevation is accurate and cannot be disturbed during construction. 4) Environmental cooperation. The concrete floor that has just been constructed cannot be exposed to sunlight, wind, rain, etc. that are unfavorable to concrete health. ④ Other requirements: A. In order to avoid random cracks in the floor, the cutting time of shrinkage joints should be carried out as early as possible (within 24 hours). B. At the same time as the construction of the laser leveling machine, there should be no electric welding machines on site, and no reflective objects (such as glass windows). C. The foundation must reach a certain hardness to ensure that the laser leveling machine does not collapse when working on the ground. D. The height of the ground in the factory building shall be calibrated by Party A, and the points must be evenly distributed, and there must be no error in the levelness. E. Pouring concrete must be operated according to the requirements of Party B's technicians.

    Quality control for ultra-large laser-leveled, wear-resistant concrete floors requires a comprehensive process encompassing "pre-construction prevention, in-construction control, and post-construction acceptance." Combining the technical characteristics (laser precision leveling and the synergistic effect of wear-resistant materials) with the challenges of ultra-large-scale construction (temperature cracking, flatness control, and interface bonding), a control system is established across five core dimensions: personnel, materials, equipment, process, and environment. This can be broken down into the following key steps:   Pre-construction preparation for ultra-large flooring directly impacts subsequent quality stability, focusing on addressing three key issues: "unified technical standards, adequate resource allocation, and proactive risk mitigation." Drawing Refinement and Technical Briefing: Based on the building's function (e.g., load and flatness requirements for factories and logistics warehouses must be clearly defined), floor compartment design should be refined (extra-large areas should be divided into 6m×6m or 8m×8m compartments to avoid thermal stress cracking). Key parameters should be clarified, including laser leveling accuracy (typically ±3mm/2m), wear-resistant material dosage (approximately 5-7kg/m2 for metallic aggregates, 3-5kg/m2 for non-metallic aggregates), and concrete strength grade (minimum C30, flexural strength ≥4.0MPa). Technical briefings should be conducted for all employees, with a focus on training laser operators, concrete vibrators, and wear-resistant material spreaders to ensure that all positions understand the key technical aspects of flatness control, wear-resistant layer bonding, and crack prevention. Risk Contingency Plan Development: To address potential issues that may arise during large-scale construction (e.g., insufficient initial setting time for concrete resulting in inability to apply the wear-resistant layer, laser equipment failure resulting in uneven flatness, and cracking due to high summer temperatures), develop a contingency plan: Confirm the initial setting time of concrete with the commercial concrete mixing plant in advance (adjusted to the temperature; ≥4 hours in summer, ≥6 hours in winter), and add a retarder if necessary. Keep one or two spare sets of core concrete laser leveling components (such as laser transmitters and receivers) to prevent interruptions to construction due to equipment failure. Prepare awnings and spray cooling equipment for summer construction, and thermal blankets and electric blankets for winter construction to maintain a temperature difference between the inside and outside of the concrete at ≤25°C. Materials are the core of floor quality. Three key materials, concrete, wear-resistant materials, and surface treatment agents, require full-process inspection: Material Type Key Control Points Inspection Standards Ready-mixed concrete 1. Mix Ratio: Crushed stone particle size 5-20mm (avoid large particles that affect smoothness), sand content 35%-40%; Slump test for each truck upon arrival. Compressive/flexural test blocks are retained according to specifications (one set per 100m³; less than 100m³ is counted as one set). 2. Slump: 120 ± 20mm (slump too large will cause sanding, too small will make vibration difficult); 3. Initial Setting Time: Adapt to the construction schedule (single-chamber construction requires leveling and wear-resistant layer application to be completed before initial setting). Wear-resistant material 1. Composition: Metallic aggregates (such as iron filings and corundum) must have a carbon content ≤ 0.2%, and non-metallic aggregates (such as quartz sand) must have a hardness ≥ Mohs 7; Sampling is randomly sent for inspection upon arrival to test compressive strength (≥60MPa) and abrasion resistance (wear loss ≤0.3g/cm²). 2. Moisture Content: ≤ 1% (avoid clumping that affects spreading uniformity); 3. Adhesion: No risk of delamination at the concrete interface. Interface treatment agent Used at the interface between the concrete base and the wear-resistant layer (if separate-chamber construction requires treatment of the interface between new and old concrete), high adhesion and crack resistance are required. Bond strength is also tested upon arrival (≥1.5MPa). Expired or clumped products are strictly prohibited.   The core equipment for laser-leveling wear-resistant flooring is the concrete laser leveling. Its accuracy directly determines the flatness of the floor, so key control measures are required: Equipment Calibration: 24 hours before construction, calibrate the concrete laser leveling blade, vibrator, and laser receiver using a standard calibration ruler (2m straightedge) to ensure the laser transmitter's leveling error is ≤0.1mm/m and the screed blade's flatness error is ≤0.5mm. Equipment Selection: For very large areas (single area ≥1000㎡), a "large concrete laser leveling" (working width ≥2.5m) should be used, combined with a small walk-behind concrete laser leveling for corners (within 300mm of the wall). Equipment Maintenance: Before construction daily, check the equipment's fuel, hydraulic oil, and vibrator motor. After work, clean the screed blade and laser head to prevent concrete residue from affecting subsequent use.   Large-scale floor construction requires a "divided-cell flow" approach. The connection between processes within each cell (concrete pouring → laser leveling → wear-resistant layer application → joint cutting and maintenance) is central to quality control, requiring on-site supervision of these five key processes. Separate compartment pouring: Strictly divide the construction area according to pre-designed compartment gaps, using the "skip compartment method" (with ≥48 hours between each compartment) to avoid temperature cracking caused by continuous pouring. The "slant layer method" is used during pouring, with each layer ≤300mm thick. The placement speed is matched to the laser leveling speed (approximately 10-15 m³/h). Vibration Control: After concrete placement, first use an inserted vibrator (vibration interval ≤500mm, vibration time 15-20 seconds, until no bubbles escape) to achieve compaction. Then, use a laser leveler to perform a simultaneous "vibration + leveling" operation (vibration frequency 3000-5000 times/minute) to ensure concrete density (rebound strength must meet the standard) while avoiding excessive vibration that can cause aggregate sinking and surface sanding. Benchmark Setting: The laser transmitter must be set up in a location away from the construction area and free from vibration interference (such as nearby fixed structures). Set the laser baseline according to the design elevation and recheck the baseline every two hours to prevent transmitter drift. Working Path: The concrete laser leveling uses a staggered back-and-forth method (first pass horizontally, second pass vertically). The screed height must be fine-tuned based on the concrete slump (higher slumps, lower slumps). Ensure the finished concrete surface is ≤3mm/2m flat. (Use a 2m ruler for immediate inspection, and correct any unsatisfactory areas immediately.) Corner Treatment: For areas beyond the concrete laser leveling's reach, such as walls and column bases, manual leveling is performed using a small handheld concrete laser leveling with an aluminum alloy screed to ensure consistent flatness across the entire surface. The timing and uniformity of spreading wear-resistant material directly impacts its bond with concrete. Spreading should be done in two stages, with strict timing controls. First Spreading: After the concrete is poured and leveled, wait until the surface moisture has evaporated to the point where no visible indentation is observed when pressed with a finger (approximately 1-2 hours before initial setting). Apply 60% of the total amount of material, evenly spreading using a "plum blossom" pattern (avoiding any accumulation). After spreading, use a grinder (with a circular disc) at low speed to embed the wear-resistant material into the concrete surface. Second Spreading: 30-60 minutes after the first grinding, when the surface of the wear-resistant material has initially set, spread the remaining 40% of the wear-resistant material. Use a grinder (with a different blade) at high speed until the surface is smooth and scratch-free. Control the grinding pressure to avoid thinning the wear-resistant layer; the thickness should be ≥ 3mm. Large-area floors are most susceptible to shrinkage cracks, requiring stress relief through slitting. Key control points: Joint cutting time: Start 24-48 hours after concrete pouring (adjusted to the temperature, within 24 hours in summer and within 48 hours in winter), when the concrete strength reaches 25%-30% of the design strength (rebound value approximately 20 MPa). Avoid premature joint edge cracking and delayed joint cutting, which can cause random cracking. Joint cutting parameters: Compartment joints should be "through joints" (depth ≥ 1/3 of the floor thickness; for example, for a 150mm thick floor, the joint depth should be ≥ 50mm). Longitudinal and transverse joint spacing should be designed based on the compartment design (6-8m), with a joint width of 5-8mm. Polyurethane sealant should be applied promptly after joint cutting to prevent rainwater from seeping into the base layer. Temporary contraction joints: If the area of ​​a single compartment is large (≥ 1000 m2), temporary contraction joints (one every 3-4m, 20-30mm deep) should be installed during pouring. These temporary contraction joints will be extended to through joints during subsequent joint cutting. Inadequate curing can lead to sanding and insufficient strength on the concrete surface. Therefore, a "covering + watering" curing method is necessary. Curing Time: Within 12 hours after finishing the wear-resistant layer, immediately cover with plastic film and geotextile (to prevent rapid evaporation). Curing period: ≥7 days (if using impermeable concrete, curing period: ≥14 days). Curing Frequency: Water 3-4 times daily (increase to 5-6 times in summer) to ensure the geotextile is constantly moist to prevent the concrete surface from drying out and cracking. During winter curing, cover with a thermal blanket and maintain an ambient temperature of ≥5°C (if temperatures fall below 5°C, winter construction measures, such as adding antifreeze, are required).   After completion of ultra-large floor construction, a comprehensive inspection is required in accordance with the "Concrete Structure Construction Quality Acceptance Code" (GB50204) and the "Technical Code for Wear-Resistant Concrete Floors" (JGJ/T 337), focusing on the three core indicators of flatness, wear resistance, and crack control. Appearance Inspection: A comprehensive inspection of the floor surface is required. The floor must be free of sanding, peeling, exposed surfaces, or scratches. The wear-resistant layer must be uniform in color with no significant color variations. Crack Inspection: A crack width gauge is used to inspect for cracks. "Non-through surface cracks" (width ≤ 0.2mm) are permitted. "Through cracks" or cracks with a width greater than 0.2mm are strictly prohibited. If excessive cracks are found, the cracked area must be chiseled out (extending 100mm), and the concrete and wear-resistant layer must be re-poured. After rectification, re-inspection will be conducted. Test Items Testing Method Qualification Criteria Smoothness Using a 2m straightedge and a feeler gauge, test at five points (evenly distributed) per 100 m2, recording the maximum deviation. Deviation at any point ≤ 3mm/2m, and a pass rate ≥ 95% Abrasion Resistance Using the Taber Abrasion Test, sample a representative area (100 mm × 100 mm) and weigh it after 500 cycles of abrasion. Abrasion loss ≤ 0.3g/cm² (metal aggregate wear layer), ≤ 0.5g/cm² (non-metal aggregate wear layer) Compressive Strength Concrete test blocks were collected according to specifications (one per 1000 m2) and tested after 28 days of standard curing. Concrete compressive strength ≥ design value (e.g., C30 ≥ 30MPa), flexural strength ≥ 4.0MPa Adhesive Strength Using the Pull-Out Test, samples (50 mm diameter) were taken at the interface between the wear-resistant layer and concrete, and the pull-out strength was measured. Bond strength ≥ 1.0MPa, with failure mode being "cohesive failure of concrete" (not interfacial debonding) After acceptance, finished product protection measures must be implemented to prevent subsequent construction (such as equipment installation and pipeline laying) from damaging the floor: Do not allow heavy equipment (such as forklifts or cranes) to directly roll over the floor (a steel plate is required). Avoid sharp objects (such as rebar or steel pipes) from striking the floor surface. If holes need to be drilled in the floor (e.g., to install a floor drain), use specialized drilling equipment. Manual chiseling is strictly prohibited to prevent cracking of the surrounding concrete.   Large-scale floor construction is susceptible to extreme environmental impacts, such as high temperatures, low temperatures, and strong winds. Targeted adjustments to control measures are required: During high-temperature construction (temperature ≥30°C): Adjust the concrete pouring time to the morning and evening (avoid the high-temperature period of 10:00 AM to 4:00 PM); Pour the concrete immediately after arrival to avoid prolonged standing (this shortens the initial setting time); Immediately cover the wear-resistant layer after finishing to maintain moisture, and increase the watering frequency (once every hour). Low-temperature construction (temperature ≤ 5°C): Add antifreeze to the concrete (dosage according to the instructions, strictly prohibit exceeding the standard) to ensure the concrete enters the mold at a temperature ≥ 10°C. After construction, cover with a thermal blanket and electric heating blanket to maintain an ambient temperature ≥ 5°C. Extend the curing period (≥ 10 days) and remove the insulation only after the concrete strength reaches 70%. In strong winds (wind speed ≥ 5m/s): Suspend the application of the wear-resistant layer (to prevent the material from being blown away by the wind); Immediately cover the concrete with plastic sheeting after pouring (to prevent rapid evaporation of surface moisture and resulting in sanding).   Through the above full-process and multi-dimensional quality control, the three core quality problems of "poor flatness, peeling of the wear-resistant layer, and shrinkage cracks" of ultra-large-area laser-leveled wear-resistant concrete floors can be effectively solved, and ultimately the floor's "high strength, high wear resistance, and high flatness" requirements can be achieved.   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.      

The concrete construction process should be familiar to everyone.  In general, the concrete construction process is the preparation (production) of concrete–concrete transportation (transport)–concrete pouring (concrete)–concrete maintenance (conservation), In this chapter, we mainly share the three parts of the concrete pouring process, which is divided into the foundation concrete pouring construction process, the wall column concrete construction process. And the beam and slab concrete construction process, so that everyone can understand the concrete parts of these important parts in detail. Pouring construction technology and process, in order to master the concrete construction rhythm in the actual concrete pouring process, so that the real-time control in the process, there are inspections and acceptances have been rectified, to ensure the concrete pouring molding effect and beauty, to achieve excellent quality! Section 1: Foundation pouring construction technology In the following chapters, we will introduce the concrete materials and the matters needing attention during transportation. This section will directly introduce the construction process of the foundation rafting. Before the official start, everyone can think about concrete construction from preparation to pouring. Complete, what preparations do we need, what conditions should be provided before pouring, what work needs to be done when pouring, what needs to be done after the pouring is completed, please remember one magic weapon, that is, the man-made method of the master key Ring", as long as the factors are sorted out in order from these factors, it will be ok, then take a look at the basic rafting construction process. First of all, let's talk about the concrete project quality control program. The basic main line of each project is to use this control program. You can optimize this program according to your own project, better prepare for the event, process control, and follow-up afterwards. Perfect, better to improve the quality of cast-in-place concrete. Section 2: Construction Deployment The foundation concrete is made of commodity ready-mixed concrete. According to the construction process and construction schedule, the concrete pouring should be arranged as much as possible during the day. If the concrete pouring amount is large, the construction can be divided into two shifts if the construction can not be completed during the day and the construction joint cannot be left. Class 12h, relevant professional leaders and construction personnel follow the class operation, responsible for inspection, and at the same time do a good job in coordination. (There is no extension of the night construction to disturb the people) Whether the foundation concrete is cast by the day pump or the ground pump is used together, and the specific conditions are determined according to the actual conditions of the project and the construction period requirements. The contents of the construction preparation will be shared in the next article.