Mechanical Properties and Freezing and Thawing Resistance of High-Strength Concrete Incorporating Silica Fume

Abstract

Abstract This report presents results of an investigation dealing with the mechanical properties and freezing and thawing resistance of high-strength, silica fume concrete using ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666-84, Procedure A). Eighteen nonair-entrained and six air-entrained concrete mixtures, 0.06 m3 in size, were made. The water-to-(cement + silica fume) ratio (W/C + S) of the mixtures ranged from 0.25 to 0.36, and the percentages of cement replacement by silica fume were 0, 10, and 20% on a weight basis. Any loss in slump due to the use of silica fume was compensated for by the use of a superplasticizer. A number of test cylinders were made for testing in compression at various ages, and test prisms were cast for determining their resistance to repeated cycles of freezing and thawing in accordance with ASTM C 666, Procedure A. Sawn sections of some of the prisms were used for determining the air void parameters of the hardened concrete. Nonair-entrained, high-strength concrete with a compressive strength of up to 87 MPa at 28 days, regardless of the W/C + S and irrespective of the silica fume content used, had durability factors less than 12 when tested in accordance with ASTM C 666, Procedure A. Also, air-entrained concrete prisms incorporating 10 and 20% silica fume as replacement for cement failed to complete 300 cycles of freezing and thawing.