Quality control during concrete construction

Previously we have writen an article about Laser screed machine how to distinct its purchasability , now we will tell about quality control during concrete construction.

Quality control during concrete construction have 20 steps in this article.

1 Setting level line at the side of the wall: as laser screed machine can’t touch the wall, area where is 200-300mm away from the wall should be leveled by manual work. So level line is need to be settled as reference of artificial leveling. Meanwhile, set 2-3 undisturbed level lines (floor scale height ±0.0) at one time during construction, the level lines should be set to allow workers to see the other when work on one of them. Precision of level line is ±0.1mm.

2 Setting template( steel template, the position is in accordance with design requirement) along stand column, so as to form separation seam. Top scale height of template should between +0 and -0.2mm, in case that flatness and levelness at joint is affected.

3 Install construction joint template along the area where is going to be poured( steel template is suggested), holes of 300mm space should be reserved, in order to plug in dowel steel. Top scale height of template should between +0mm and -2mm, in case that joint between different carbins occurs large deviation.

4 Setting polystyrene sheet (thickness about 5mm) along wall, equipment foundation and stand column, to reserve separation joint and avoid craze of concrete floor.

5 Smearing oil on template

6 Placement of laser emitter: it should be placed on column. Detailed position should be decided according to concrete placing quantity. If placement on column can not be accomplished, then it should be placed on special triangle.

laser screed
laser screed

7) Transporting concrete to the site: transportation speed of concrete should be at less 60m3/hour with even speed, pause interval should be decreased, to avoid cold junction. If pause interval is more than 45 minutes, there should be settled a construction joint and constant construction is not suggested.

8 To guarantee quality of concrete floor to be poured, there should be 8-10 workers in each group to cooperate with each other, push aside surface of concrete which is placed on floor and make them smooth, make the piled material a little higher (about 10mm) than designed scale height. Meanwhile arrange 2 workers around wall, outcrop pipeline and template to trowel  (use darby slicker of 2m and plasterer’s trowel) concrete 20 cm away around them. Workers who are in charge of troweling must be skillful plasterer.

9 As thickness of concrete reaches to 350mm, bistratal and bidirectional bar-mat reinforcement are set, to guarantee close-grained of concrete vibratory, this project requires for a vibrating needle to conduct vibration.

10 Width of concrete material poured on platform each time should be no less than 6m, its length is decided by boarder of template. Construction direction from left to right (along short side direction), from front to back (along long side direction). Placing and pouring quantity is suggested to be 1500-2000m2. Use groove profile trowel to trowel the site quarterly after leveling through concrete laser screed machine.

laser screed
laser screed

11 After initial condensation. Use trowel machine (equipped with circular plate) to construct the site when footprint stepped by a person is 3mm deep, twist mortar on the surface equably, then use leveling trowel with a length of 3m to striking ridgy concrete surface (specially area where is around the part troweled by worker) in some area, at last, equably bestrew two thirds of metal aggregate wear-resisting flooring hardener on compacted concrete surface.   

12 As hardener bestrewed by man hand may not equably, leveling trowel is needed to be used to trowel hardener material and then use trowel machine (circular plate) to press it into concrete. Then bestrew the remaining one third hardener. Then use leveling trowel to conduct partial maintenance.

13 Use circular trowel machine to finish the construction site lengthways and athwartships twice. 

14 At last use trowel blade on trowel machine to conduct repairing work on the surface, for edges (such as side of wall) where trowel machine can not touch to, labor is require to do the repairing.  

15 Maintenance. For floor where seal solidification agent is not required, curing agent is suggested to be used for maintenance. For floor where other surface coating (such as epikote) is required in the future, the surface is not recommended to use hardener, in case that effect of surface will be effected. Concrete floor which is just constructed mustn’t bare to environment that is adverse to maintenance of concrete such as sunshine, wind and rain.

laser screed
laser screed

16 Template removal ( including template around stand column), please note that do not damage the corner.

17 Cutting control joint: cutting in accordance with designed space and depth requirements. If no requirements for design, keep 6m distance during cutting is suggested(if there is designed requirements, take is as criterion), cutting should be conducted in the best cutting time( within 24 hours without breaking concrete surface). To avoid inconformity of surface color, sewage should be collected (through cleaner) immediately after cutting.

18 Clean polystyrene filler strip along wall, fill it with polyurethane after 28 days.

19 All cutting joints and construction joints are filled with polyurethane after 28 days. Pour concrete to template of stand column.

20 Ensure that concrete supply speed reaches to 60m3 per hour or more, and initial condensation time of each batch of concrete should be the same.

if you want to know more about construction of concrete by laser screed, please refer to Laser screed flooring one-stop concrete construction technology .

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