ZEMCH 2015 - International Conference Proceedings | Page 780

Figure 4: Lengths frequency
The designed minimum characteristics required for the reinforced mixtures were a workability
class at least S4 (fluid concrete) according to (UNI EN 206-1 2006) and a compressive strength after
28 days, Rcm(28)=30 MPa. The variable parameters of the experimental work were the type of mixture (Plain or Fibre Reinforced) and the type of steel fibres (Industrial or Recycled), The ordinary
concrete was used as a reference to compare the obtained results, in terms of fresh and hardened
properties.

Materials
Ordinary Portland cement, according to the requirements of the adopted standard (UNI EN 197-1
2006), was used for the mixtures. A high-range water-reducing admixture was added to improve
the fresh concrete workability. Water, limestone aggregates and locally available sand were also
used. Three different grain sizes were used for all the mixtures and the sieve analysis (UNI EN 933
1999) is illustrated in Fig. 5.
100

Cumulative passing [%]

90
80
70

Sand
Aggregate I
Aggregate II

60
50
40
30
20
10
0
0,01

0,1

1

10

100

log (d)

Figure 5: Introduction of the fibres into the mixer

778

ZEMCH 2015 | International Conference | Bari - Lecce, Italy