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Home arrow Engineering arrow Creep Behaviour in Cracked Sections of Fibre Reinforced Concrete: Proceedings of the International RILEM Workshop FRC-CREEP 2016

Experimental Program

Materials and Characterization

The mix used in the experimental program was a self-compacting SFRC, with a 70 MPa nominal compressive strength at 28 days. The mix contained Portland cement, sand, crushed aggregates with a continuous grading and a maximal diameter of 10 mm, high-range water-reducing admixture, water, and 78 kg/m3 (1 %-volume) of Dramix ZP-305 steel fibres. These fibres are filaments of wire with a diameter of 0.55 mm, deformed into a hooked shape, and cut to a length of 30 mm giving an aspect ratio (l/d) equal to 55. The mixture proportions are summarized in Table 1.

Characterization specimens and flexural creep beams were unmolded after 24 h, then cured for 7 days at 100 % relative humidity, and finally were kept in air in a controlled environment room at 50 ± 5 % relative humidity and 23 ± 2 °C until

Table 1 Mixture proportions

Component

Quantity (kg/m3)

Cement (CEM1 type)

650

Sand (calcareous)

843

Aggregate (calcareous)

622

Fibres (steel)

78.0

Superplasticizer

38.4

Water

195

they were tested. 7-day of humid curing is required in Canada for concrete structures exposed to freeze-thaw and chlorides [7]. Flexural creep beams were cured 6 months to minimize the variation of material properties due to concrete aging between the first and last flexural creep tests.

The mean mechanical properties at 28 days of the studied SFRC were: fc = 75.7, ft = 4.31, Ec = 35 800 MPa, module of rupture (MOR) = 41.8 MPa. fc and Ec were measured on 3 specimens, ft and MOR on 6 specimens.

 
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