Curing a Concrete slab

The purpose of curing is to reduce the rate of heat loss of fresly poured concrete, it continues to at least 3 days and it's recommend to be 7 days, increased thermal stresses will affect on strutural strength of concrete.

For a slab structures, tow methods may used ponding and covering by polyethylene sheets.

Ponding: this method of curing by covering the concrete with water, the main disadvantage of this method is it's consume more water need to be disposes off the site after finishing curing.

Polyethylene sheets : this method of curing is based on no evaporation can take place at top of the freshly poured concrete by covering the concrete with this sheets. One of disadvantage of this method is wind can easily blown off it so the performance of curing may be affected.

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Differences between development length, anchorage length and splice length

1-Development length Ld It is the minimum length of a reinforcing bar that must be embedded or "developed" in concrete to ensure that the bar can achieve its full strength in tension or compression. 2-Anchorage length La The distance that the reinforcement extends from the point where the bars are no longer required to resist moments 3-Splice length LS The distance require to transfer the force from bar to another one to upload full presentation please download this https://drive.google.com/file/d/1layyDvTlJOLzo3jfoW4K5O5UEkgoEzgN/view?usp=sharing

KEYSTONE RETAINING WALL

Introduction:- Keystone is a mechanical stabilized earth wall MSEW which used to retain soil from one side, it's less cost than concrete walls. Material 1-Keystone Blocks 2-Fiberglass Pins 3-Geo-grids 4- Back-filling Material 5-Concrete pad Different type of Geogrid: TT045 can carry load till 45KN/m. TT060 can carry load till. 60KN/m. TT090 can carry load till 90KN/m. TT120 can carry load till 120KN/m. TT160 can carry load till. 160KN/m. Method Statement 1) Place HDPE Geogrids on top of the compacted soil. HDPE Geogrids are installed from the front on top of the fiber glass pins (which penetrates the grid) and from to back, Geogrids are fixed horizontally using a steel bars. 2) Lay down the precast concrete units on top of a PC foundation at a level that is a Minimum of 5% from the wall height and reach 10% (buried height) to prevent any lateral movement . 3) Put the layers of Geotextile. 4) Backfilling using fine gravel b...

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