Paraffin wax as an internal curing agent in ordinary concrete

Curing of concrete involves maintaining satisfactory moisture content during early stages to develop the desired properties. Properly cured concrete has improved durability and surface hardness, and is less permeable. Prevention of loss of moisture is important not only for strength development but also to prevent plastic shrinkage, for decreased permeability and to improve resistance to abrasion. Good and complete curing is not always practical for several reasons, particularly in higher grade concretes. Using self-curing agents can solve this problem. The concept of self-curing agents is to reduce water evaporation from concrete, and hence increase its water retention capacity compared to conventional curing. Several materials, including polymeric glycol and paraffin wax, can act as self-curing compounds. This study investigates the role of paraffin wax as a self-curing agent and compares this with the effect of different curing regimes simulating traditional methods of curing. The parameters include grade of concrete, type and dosage of paraffin wax, curing conditions and age of curing. Weight loss and compressive strength are determined as a performance benchmark for the investigated curing compounds. It is found that the lower dosage (0.1%) liquid paraffin wax compounds act as the best curing compounds in higher grade concretes.