Long-term mechanical properties and durability characteristics of high-strength/high-performance concrete incorporating supplementary cementing materials under outdoor exposure conditions

This paper presents the results of tests performed on the compressive stren gth of high-strength/high-performance concrete at ages up to 10 years, the modulus of elasticity after 2, 4, and 10 years, and the carbonation depth a nd the resistance of concrete to chloride-ion penetration after Ia years. T he tests were performed an drilled cores taken from the structural test ele ments simulating concrete columns. In addition, the compressive strength of cylinders cured in a moist room and in the field, as well as the compressi ve strength of drilled cores taken from the structural elements (walls) at ages up to 4 years was determined. After 10 years, the compressive strength of the cores drilled from the colu mn elements of the control portland cement concrete and concrete incorporat ing various supplementary cementing materials ranged from 86.4 to 110.3 MPa . The highest strength was obtained for the high-volume fly ash concrete fo llowed by the control portland cement concrete, slag concrete, silica fume concrete and concrete incorporating a combination of slag and silica fume, in that order. Even though the high-volume fly ash concrete at ages up to 2 8 days had lower strength than the other concretes, it attained the highest strength gain of more than 120% between 28 days and 10 years. On the contr ary, the concrete incorporating 12% silica fume had the highest compressive strength at ages rep to 28 days, but it had a strength gain of only 18% be yond that age. In general, the moduli of elasticity of the moist- and field-cured cylinder s and the cores taken from the column elements were similar. For the cores drilled from the column elements, the fly ash concrete had the highest E-mo dulus at all three ages of 2, 4, and 10 years. The experimentally determine d E-moduli ranged from 83 to 116% of the values calculated according to ACI Code 318. In tests performed in accordance with ASTM C 1202, the charge pa ssed through all the concretes at 10 pears was less than 1000 coulombs indi cating very high resistance of the concretes to the chloride-ion penetratio n. After 10 years of outdoor exposure, the depth of carbonation in all the concretes was negligible.