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Concrete creep is essentially the sagging of concrete over time. Creep and shrinkage of concrete are two physical properties of concrete.The creep of concrete, which originates from the calcium silicate hydrates (C-S-H) in the hardened Portland cement paste (which is the binder of mineral aggregates), is fundamentally different from the creep of metals and polymers.
Uncovered concrete dries from the top down. Concrete moisture meters measure only the top inch at most [5] and this area is drier than the concrete further down. Once a floor covering has been installed the moisture in the slab equilibrates. In order to ensure the equilibrated moisture will be a safe level [6] for a floor covering, a relative ...
It also causes water bleeding at the surface of concrete slabs or rafts (with a dusty surface left after water evaporation). For all the afore mentioned reasons, it is strictly forbidden to add extra water to a ready-mix concrete truck when the delivery time is exceeded, and the concrete becomes difficult to pour because it starts to set. Such ...
With elevated temperature, concrete will lose its hydration product because of water evaporation. Therefore its resistance of moisture flow of concrete decreases and the number of unhydrated cement grains grows with the loss of chemically bonded water, resulting in lower compressive strength. [12]
Epoxy moisture control systems can be applied over concrete with relative humidity levels up to 100%, and there are systems available on the market today that can be applied over concrete that is physically damp. In some cases, with the use of an epoxy moisture control system, floor coverings can be installed just 7 days after the slab is poured.
The steel shuttering pinches the top surface of a concrete slab due to the weight of the next slab being constructed. Concrete slabs, block walls and pipelines are susceptible to cracking during ground settlement, seismic tremors or other sources of vibration, and also from expansion and contraction during adverse temperature changes.
In civil engineering, concrete leveling is a procedure that attempts to correct an uneven concrete surface by altering the foundation that the surface sits upon. It is a cheaper alternative to having replacement concrete poured and is commonly performed at small businesses and private homes as well as at factories, warehouses, airports and on roads, highways and other infrastructure.
Sulfates dissolved by ground moisture migrate into the concrete of the slab where they react with different mineral phases of the hardened cement paste. The attack arises from soils containing SO 2− 4 ions, such as MgSO 4 or Na 2 SO 4 soluble and hygroscopic salts.