Mechanical properties of superplasticized fiber reinforced concrete developed for bridge decks and highway pavements

This paper presents the results of an experimental investigation of the properties of superplasticized fiher reinforced concrete. Essentially, two groups of specimens were tested; the first to study the relationship between compressive strength and modulus of rupture and the second to study time dependent behavior. Altogether, more than 70 mixture proportions were investigated. The first group of specimens was tested to obtain 28 day compressive strength and 28 day modulus of rupture. The second group of specimens was tested in compression, flexure and for impact resistance at 1, 3, 7, 28 and 90 days. Based on the experimental results, an empirical equation (similar to the one specified in the American Concrete Institute Code 318-83) is proposed, that relates 28 day compressive strength to the 28 day modulus of rupture. The results indicate that: (i) the flexural strength varies linearly with the logarithm of time, (ii) flexural strength gain with time is slower than compressive strength gain, (iii) higher cement content in combination with lower water-cement ratio results in higher early strengths, (iv) the toughness index slightly decreases with an increase in maturity, and (v) both first crack and ultimate impact resistance increase up to 28 days of maturity.