MECHANICAL PROPERTIES AND DURABILITY OF HIGH
PERFORMANCE CONCRETE INCORPORATING ULTRA FINE SLAG
AND UNDENSIFIED SILICA FUME
36th Our World in Concrete and Structures (OWICs) - 2011
Da Xu*, B. Sabet Divsholi, Darren T.Y. Lim and Susanto Teng
High performance concrete, undensified silica fume, ultra fine slag, Rapid Chloride Migration Test.
In recent years, more and more infrastructure projects require concrete to have high strength and high durability. Ultra High Performance Concrete (UHPC) has sometimes been considered as a solution. However, some drawbacks of UHPC like high cost of the constituent materials, difficulties in quality control, and strict requirements for curing regime can limit its application in mass concreting. This
research shows that a concrete consisting of Ordinary Portland Cement (OPC) plus ultra fine mineral admixtures and locally available aggregates with maximum size of 20mm can achieve compressive strength as high as 135MPa at 28 days under normal water curing condition. Two mixes of OPC concrete were cast, one with 10% Undensified Silica Fume (USF) replacement, and the other one with 10% USF and 30% Ultra Fine Ground Granulated Blast-furnace Slag (UFGGBS) replacement. The water/cementitious ratio was set to 0.25 and the total cementitious materials content was 580 kg/m3. The behaviour of the fresh concretes were studied and the relevant specimens were water cured for 3, 7, 28, 56 and 90 days. In addition to the development of compressive strength, the flexural strength, modulus of elasticity, and electrical resistivity of the concrete were studied. Rapid Chloride Migration Test (RCMT) from Nordtest NT build 492 was used to check the chloride ion resistance of the concrete by calculating the chloride migration coefficient. These mixes perform extremely well in terms of workability as well as mechanical properties and RCMT results.