Concrete laser screed machine is a high-precision equipment which accomplish fast leveling through real time control of leveling head by laser receiver.
As the development of economic society, requirements for floor quality such as strength, flatness and levelness of modern industrial, large supermarket, warehouse and other large area of cement concrete floor is increasingly higher, concrete laser screed machine is developed as a convenient tool to meet those requirements and create superflat floor.
Construction requirements for concrete and template before use of concrete laser screed machine to construct superflat floor.
1 Concrete construction requirements
- The concrete must be produced transported to superflat floor project site by commodity concrete manufacturer.
- Specification of concrete: C25-C30 concrete, strength no less than 25mpa in 28 days, details in accordance with design requirements.
- Water cement ratio: no more than 0.5, water shall not be added optionally during feeding.
- Cement: general portland cement no less than grade 42.5.
- Aggregate: excellent grade of aggregate. Use broken granite or scree as coarse aggregate. The max diameter no less than 25mm. Use clean river sand as fine aggregate, fineness modulus 2.4-2.7.
- Concrete mix proportion: cement quantity no less than 350kg/m3. In order to avoid quality problem generated on surface, sand coarse aggregate ratio shall be 35%-40%.
- Concrete slump: 14±2cm, max 16cm.
- Condensation period: initial condensation shall be 3-5 hours.
2 Template of superflat floor
In order to avoid oversize error of surface scale height on joint, steel template shall be applied. Scale height of template shall be between +0 and -2mm, steel template shall be placed 1-1.2m far from walls.
Concrete laser screed machine comes in handy after pouring of concrete. Now we will begin to introduce it.
Leveling of concrete laser screed machine
Laser leveling method is adopted by computer, so pulling control line is not needed, neither does conventional labor work to control floor scale height. The scale height is controlled by computer in real time and control frequency is 10 t/s, floor scale height can be controlled accurately.
Once initialization is finished, wherever the concrete laser screed moves to, scale height of the floor entirety poured won’t be affected
Leveling technology of concrete laser screed in superflat floor area
Scraper blade: used for scrape of over height concrete material, the remaining material of 19.1m height is left and constructed by spiral.
Feeding spiral: it rotates to single direction, from left to right, cuts concrete material and distribute it to required scale height.
Vibrator and leveling beam: vibration is generated by electric block, frequency is 3000 times/min, it drives the whole leveling beam and generates vibration and execute compaction.
if you want to know more about concrete laser screed, please refer to Hiking store.
One. Preparatory work before use of trowel machine
1. Construction of wear-resistant coat
Finishing pouring of concrete, use rubber tube or vacuum equipment to remove bleeding, repeat that step more than twice then begin to construct wear-resistant material. constructors shall wear flat bottomed rubber shoes in the middle stage of wear-resistant material construction and water-proof paper shoes in the last stage.
2. First bestrewing, troweling and pressing of wear-resistant material
1) Time or opportunity that bestrew wear-resistant is changed by climate, temperature and mix proportion of concrete. Earlier bestrewing will cause the wear-resistant material sink into concrete and lose effect; while later bestrewing will lose adhesive property and hinder wear-resistant material from combining with concrete and cause stripping because the concrete have been solidified. The way to decide bestrewing time is to stamp on it, when it sink 5mm, you can begin to the first bestrewing.
2) Water desorption on side boundary such as wall, column and formwork is fast, so those places should be constructed preferentially to avoid decrease of effect caused by water desorption;
3) quantity of bestrewing for the first time is two thirds of the whole quantity, mixture should be dropped down equably, use wooden trowel to float after bestrew. After wear-resistant material absorbs enough water, use round trowel machine of 1m to milling.
Two. Construction by trowel machine
1.Usage of trowel machine to Bestrew, trowel and float wear-resistant material for the second time
- use guiding rule or straight floating rule to measure levelness in the second bestrewing and adjust unevenness, direction of the second bestrewing should be vertical with that of the first bestrewing.
2) quantity of bestrewing for the second time is one third of the whole quantity, troweling and floating should be executed immediately after bestrew, replaced the roundle by four-patch trowel slice, use trowel machine to work for more than twice. The machine should work lengthways and horizontally in a uniform and orderly way, avoid aggregation of material. Corner should be treated by woody trowel.
3) when the surface material is hardened enough that it can be sunken by finger pressing, rotation and angle of trowel machine shall by adjusted according to hardness, The machine should work lengthways and horizontally more than three times.
surface modification and maintenance
- texture left on the surface after construction of trowel machine is a bit messy, in order to eliminate the texture, the last step is to press and float the surface orderly in one direction by thin steel.
2). after wear-resistance floor has been constructed for 5-6 hours, splash curing compound for maintenance, quantity of curing compound is 0． 2 litre per square meters or cover plastic film to prevent craze from water desorption, splash water for one week .
3). after wear-resistance floor has been construction for 24 hours, the film can be taken down, please not to damage edge of the floor.
If you want to get more information about trowel machine, please refer to Operation of trowel machine and attentions need to be paid
In floor construction a good trowel machine is required, Hiking trowel machines have been introduced to many projects, they are highly praised by our customers. We supply both ride on trowel machine and walk behind trowel machine, we have whichever you want. See Hiking store
Overview of laser screed
Laser screed is an unique equipment that execute high-precision and fast leveling of concrete construction through real-time control of leveling head. This machine is developed for increasing demand for floor quality of concrete floor used in large areas such as workshop, large supermarket and so on. it takes laser as its datum plane and adopts imported receive and emission system. Use of laser screed bring much convenience to projects construction.
Automatic laser control system of this machine ensures an accurate leveling through the use of electronic or hydraulic controls . Laser receivers mounted at each end of the screed head receive a signal from a transmitter multiple times per second providing totally automatic control to finished floor. Concrete floor paved by fine laser screed is much better than floor that paved by conventional method. Meanwhile, laser screed machine saves labor cost.
Some users are not familiar with operation of laser screed, now we will write something about it.
Detailed introduction for operation of laser screed
- Arrange one operator to check the equipment before construction, set up emitter and install handheld receiver; adjust scraper in stationary state, non deviation should be exist between the two points; operate laser screed to observe if the machine is working normally, check if laser receiver is on horizontal position, supervise if supplementary staff pull down or fill in material in time; after construction, clean the laser screed when it is cooling, see if all function of the machine is normal and check electric quantity.
- Arrange one staff to assist installation and debugging machine, set up emitter, install hand receiver. Check if placement position of emitter is safe; measure height of the concrete paved (height scope 2mm≥，≤10mm); measure height of the concrete leveled (no less than -2mm and no more than 3mm);
- Arrange two supplmentary staffs before operating laser screed, execute initial pavement to concrete; when machine follow machine the operator shall obey supervisor’s command, pull down and fill concrete to scraper (concrete material no lower than edge of scraper, no 35mm higher than the edge)
- Paving worker must obey the guidance of the person who control the operating rod of the machine when execute initial pavement of concrete.
How to maintain laser screed machine
- Liquid crystal display on laser screed is also need to be clean up, you can use organic resin or cleaning cloth that specially used for glass to wipe dirt.
- If the machine need to start again during construction because laser signal is lost interval time must be longer than 10 seconds.
- If there are too many stains, you can put a soft cloth into neutral cleanser that diluted by water, wring out the cloth and use it clean your machine, We suggest you never use chemicals such as naphtha, diluent and gasoline to clean your machine.
If you want to know more about laser screed, please refer to concrete laser screed on Hiking website.