Application of high-strength/superworkable concrete to thin-wall prestressed concrete products

摘要

Undertaken to develop a practical vertical casting method that can be applied to manufacture efficiently thin-wall prestressed concrete products with high strength (f_ck = 70 Mpa), the work presented in this paper included the development of superworkable concrete made by adding 15-20/100 fine limestone powder (Blaine specific surface area 7310 cm~2/g) to high-early-strength Portland cement along with a polycarboxylic-acid-type air-entraining superplasticizer and viscosity agent (natural polysaccharide polymer of type β-glucan) solution. This was followed by the laboratory testing and trial production of this superworkable concrete at an actual plant to study its suitability as a material for densely reinforced, thin-wall prestressed concrete products. The study confirmed that neither the addition of a viscosity agent (β-glucan) nor the quantity of fine limestone powder added has any effect on the freezing and thawing resistance or the sulphate resistance of superworkable concrete.