PSI - Issue 5

P.C. Raposo et al. / Procedia Structural Integrity 5 (2017) 1092–1096 Raposo et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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1095

In Fig. 5 is presented the mineral and binder composition of the second layer of the plaster plate removed of the partition wall. Table 2 shows the principal characteristics observed in the petrographic microscope. Figure 6 is showed the third layer mineral composition for the plaster plate. This layer is composed by three sublayers that are characterized in Table 3.

Fig. 5. Petrographic analysis of the 2 nd sublayer for the plaster plate: (left) Results obtained from natural light; (right) Results obtained from polarized light (F – crack; M – micas; Q – quartz; L – Binders).

Table 2. Petrographic characteristics of the 2 nd layer of the plaster plate removed of the partition wall.

Layer/trace

Minerals

Dimensions (mm)

Observations

Quartz

1

2 nd 1 part lime : 1part gypsum : 4 parts white sand [13]

The layer has a large quantity of binder, porosity and cracking. The most common mineral is quartz (has rounded limits that indicates the fluvial origin), also has micas (angular).

Feldspars

1 1

Micas

Fig. 6. Petrographic images of the 3 rd sublayer for the plaster plate: (left) Results obtained from natural light; (right) Results obtained from polarized light (1 – first finishing; 2 – second finishing; 3 – third finishing).

Table 3. Petrographic results for the 3 rd layer of the plaster plate removed of the partition wall.

Layer/Trace

Materials Iron oxide

Thickness (mm)

Observations

1 st sublayer 2 nd sublayer 3 rd sublayer

0.5

-

3 rd 1 part lime : 1 part sand [13]

Lime

Gypsum

0.15 0.15

Regularization layer

Lime

-

Iron oxide