Shrinkage calcium chloride

Direct addition of water-reducing admixture This increases the workability of the concrete. The effect of all types of water-reducing admixture under these conditions is invariably to increase the shrinkage and creep of the concrete. Some typical values are shown in Table 1.31. The considerable increases in both shrinkage and creep in the presence of admixtures containing calcium chloride and triethanolamine are clearly illustrated. 

Table 5.6 Drying shrinkage of concretes containing calcium chloride, triethanolamine and calcium formate...

The drying shrinkage of concrete containing calcium chloride is increased in comparison to plain concrete, even though the amount of moisture lost is less [22]. This is illustrated in Fig. 5.37 and it is thought that the reduced moisture loss will be due to the more advanced state of hydration in the specimens containing calcium chloride. The increased shrinkage must, therefore, be a characteristic of the type of cement hydration products formed. Under saturated conditions, such as total water immersion, the amount of expansion of the concrete is reduced when calcium chloride is present. 

Calcium chloride increases both drying shrinkage and creep. 

While calcium chloride tends to decrease permeability of concrete, its corrosive influence and ability to increase shrinkage make it a potential hazard to long-term durability in reinforced concrete. 

High dosage rates or, occasionally, normal dosage rates with high cement content mixes may cause rapid stiffening and considerable heat evolution with consequent risk of thermal and shrinkage cracking. Calcium chloride in particular should be used with care in hot weather. 

ADVANTAGES AND DISADVANTAGES OF THE BLEND Reduced water absorption, lower shrinkage, improved heat aging and impact resistance, primerless paintability, higher resistance to polar solvents, such as methanol, gasohol, and resistance to cracking on exposure to metal halides, such as calcium chloride, are achieved compared with PA-66 and PA-6. 

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