Civil Engineering Reference
In-Depth Information
Table 7.1
Chemical composition of natural pozzolans formerly tested in HVNP
systems (% by weight)
LOI
*
Pozzolan
no.
SiO
2
Al
2
O
3
Fe
2
O
3
CaO
MgO Na
2
O
K
2
O
SO
3
Ref.
1
62.3
15.0
5.1
4.9
1.2
2.2
1.8
0.2
6.3
Uzal and Turanli
(2003)
2
61.7
16.2
3.5
5.0
1.5
3.5
2.4
0.1
5.9
3
61.5
18.2
3.8
4.6
0.9
3.9
4.1
0.1
2.7
Turanli et al.
(2004)
4
54.2
15.2
6.4
8.8
2.4
1.5
2.1
0.5
11.6
5
62.2
15.2
3.3
4.9
1.5
3.5
2.4
0.5
6.1
n.a.
**
6
69.3
11.4
1.3
1.7
0.8
1.0
4.0
6.2
Uzal and Turanli
(2012)
n.a.
**
7
66.1
11.0
1.1
3.7
1.0
0.2
1.8
9.4
8
71.0
13.4
1.2
1.7
0.3
3.2
4.7
-
3.3
Uzal et al.
(2007)
9
54.2
14.8
5.6
7.3
2.7
1.0
1.2
0.1
12.7
*
LOI: Loss on ignition.
**
n.a.: Not available.
Table 7.2
Qualitative mineral composition of the natural pozzolans formerly tested
in HVNP systems
Pozzolan
no.
Glass Quartz Cristobalite
Albite Calcite Clinoptilolite Ref.
1
+
-
-
+
+
+
Uzal and Turanli
(2003)
2
+
-
-
+
-
-
3
+
+
-
+
-
-
Turanli et al.
(2004)
4
+
+
-
+
-
+
5
+
-
-
+
-
-
6
-
-
-
-
-
+
Uzal and Turanli
(2012)
7
-
-
-
-
-
+
8
+
+
+
+
-
-
Uzal et al.
(2007)
9
+
+
-
+
+
+
The common minerals present in natural pozzolans are glass, quartz,
feldspar, mica and analcime. In some deposits, glassy phases in volcanic tuffs
transform into crystalline zeolitic minerals. The nature of zeolitization and the
type of the resulting zeolitic mineral depend on hydrothermal conditions in
the geology of the deposit. On the other hand, geological transformation of
glassy phases in natural materials of volcanic origin may result in formation
of clay minerals (argillation process). zeolitization improves the pozzolanic
activity of volcanic materials whereas argillation decreases it (Massazza,
2001). The mineral composition of some of the natural pozzolans formerly
used in studies on HVNP cementitious systems as determined by X-ray
diffraction (XRD) analysis is shown in Table 7.2.
