25-02-2015, 12:15 PM
advantages and disadvantages of self curing concrete
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advantages and disadvantages of self curing concrete
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advantages and disadvantages of self curing concrete
09-03-2017, 03:51 PM
Concrete curing is the process of keeping the concrete under a specific environmental condition to promote hydration by controlling the temperature and moisture movement from and to the concrete. Concrete curing is done to increase the strength and stability of the concrete. The concrete curing method is decided according to the working procedure and the climatic conditions.
Need for self-healing
When the mineral mixtures react completely in a mixed cement system, their demand for curing water (external or internal) may be much higher than that of conventional ordinary Portland cement. When this water is not readily available, due to capillary porosity leakage, for example, significant autogenous deformation and cracking (early in age) can occur.
Due to the chemical contraction that occurs during the hydration of the cement, empty pores are created inside the cement paste, which leads to a reduction of its internal relative humidity and also to the contraction that can cause early cracking. This situation is intensified in HPC (compared to conventional concrete) due to its generally higher cement content, reduced water / cement ratio (w / c) and pozzolanic mineral mixtures (fly ash, silica). Empty pores created during self-drying induce contraction stresses and also influence the kinetics of the cement hydration process, limiting the final degree of hydration. The resistance achieved by IC could be more than possible under saturated curing conditions.
Often, especially in HPC, it is not readily possible to provide curing water from the top surface at the rate required to satisfy the ongoing chemical shrinkage, because of the extremely low permeabilities that are often achieved.
Potential IC Materials.
The following materials may provide internal water tanks:
• Lightweight aggregate (natural and synthetic, expanded slate),
• LWS sand (Water absorption = 17%)
• LWA 19 mm thick (water absorption = 20%)
• Superabsorbent polymers (SAP) (size 60-300 mm)
• SRA (shrinkage reducing additive) (propylene glycol type, ie polyethylene glycol)
• Wood dust
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