Issue 10

B. Chiaia et alii, Frattura ed Integrità Strutturale, 10 (2009) 29-37; DOI: 10.3221/IGF-ESIS.10.04 33 Similarly, in the second stage, when σ 3 = const . and P increases, the values of deviatoric load, the relative displacement between the specimen’s ends, and the longitudinal displacement along the lateral surface (taken by the LVDTs of Fig.5a) are measured. Two types of self-consolidating concrete (SC_mix1 and SC_mix2) and a single ordinary concrete (NC) were tested. Figure 5 : The two stages of triaxial tests on cement-based cylinders. Their compositions and strengths are reported in Tab. 1 . Specifically, the self-consolidating concretes have the same unit weight, but different amounts of aggregates. With respect to SC_mix1, in a cube meter of SC_mix2 the content of carbonate filler was increased by 90 N and, contemporarily, the weight of coarse aggregate was reduced by the same quantity. Regarding the Fiber-reinforced Self-consolidated concrete (i.e., Simabeton), two specimens were tested, under uniaxial compression (σ 3 = 0). As indicated in Tab. 1, Sismabeton is reinforced with 700 N/m 3 of Dramix RC 65/35 BN steel fibers having hooked ends (length L = 35 mm, diameter Φ = 0.55 mm, volume fraction V f = 0.9%). which were added to the self-consolidating concrete with the higher quantity of filler (i.e., SC_mix2). NC SC_mix 1 SC_mix 2 Sismabeton Component N/m 3 N/m 3 N/m 3 N/m 3 Water 1770 1770 1770 1770 Superplasticizer (Addiment Compactcrete 39/T100) - 44 44 44 Superplasticizer (Addiment Compactcrete 39/T11) 14 - - - Cement (Buzzi Unicem II/A-LL 42.5 R) 2840 2450 2450 2450 Carbonate filler (Nicem Carb VG1-2) 0 3240 3730 3730 Fine aggregate (0-4 mm) 8830 8930 8930 8930 Coarse aggregate (6.3-12 mm) 6380 6380 5890 5890 Steel fibers Dramix RC 65/35 BN - - - 700 Cubic strength -MPa- 30.0 31.1 30.4 33.8 Table 1 : Compositions and strengths of NC, SC_mix1, SC_mix2, and Sismabeton. The specimens of each concrete mixture were cast simultaneously in polystyrene form, then cured for one week under identical laboratory conditions, and finally tested after one month. Three couples of cylinders, with H =140 mm and D =70 mm, were made of NC (NC0 and NC1), SC_mix1 (SC0 and SC1), and SC_mix2 (SC0b and SC1b). The two specimens of