Page 43 - Riem-Vol6_nº3

395 IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
M.S. RODRIGUES | G.C.S. FERREIRA | L. SHIROMA | A.L. BERALDO
3.2 Pozzolanic evaluation
In order to evaluate the reactivity of RHA, the electrical conductivity
of a solution of CH/ash was measured, which was also carried out
for SF. The curves are shown in Figure 5.
It was observed that the CH/SF solution is highly reactive, with
large decreases in conductivity in the first hours. This behavior
was already expected, as SF is well known as pozzolan. The
the fine material fills the voids and presents the effect of a “filler”.
With the combination of these two positive effects, a material
might partially replace the cement with advantage, as it does not
imply a large increase in water/binder ratio (Cordeiro [22]). In this
work, it was observed a small increase of water/binder ratio in
blocks produced with replacement (by SF or by RHA), due to the
fineness of the materials.
Figure 2 – XRD pattern of SF
0 10 20 30 40 50 60 70
0
500
1000
Counts
Position (2 theta degrees)
Figure 3 – XRD pattern of RHA
0 10 20 30 40 50 60 70
0
1000
2000
3000
4000
5000
Counts
Position (2 theta degrees)
C
C
C
Q C
C CC C C C C C C
Q - quartz
C - cristobalite
Table 3 – Particle size distribution
Samples D (μm)10 D (μm)50 D (μm)90 Average (μm)
RHA
SF
4.725
3.945
26.964
18.983
79.686
42.466
35.489
21.315
Figure 4 – Particle size distribution of samples
Figure 5 – Electrical conductivity curve of samples