Preparation of Hardened Cement Paste Specimens for Monolith Leaching Test

A sample of WBFA was dry-mixed with Portland cement (CEM I 42.5R) with an ash-to-cement ratio of 30:70 by mass, and the resulting blended cement (binder) was used for environmental compatibility studies. Table 10.2 gives the chemical

Table 10.2 Chemical and mineralogical compositions of Portland cement

Component

Percentage (w/w)

Bogue potential constituenta

Percentage (w/w)

CaO

63.0

C3S

54.6

Free CaO

0.70

C2S

16.3

SiO2

20.0

C3A

9.23

Al2O3

5.04

C4AF

7.42

Fe2O3

2.44

MgO

1.35

Na2O

0.30

K2O

1.12

P2O5

0.13

SO3

3.36

Cl

0.01

LOI at 950°C

1.74

aCement chemistry notation is used: C is CaO; S is SiO2; A is Al2O3; F is Fe2O3.

and mineralogical compositions of the Portland cement, the composition of the latter being calculated by the Bogue method.

Cement pastes were prepared manually by using the blended cement and deio­nized water as mixing water, at a water-to-binder weight ratio (w/b) of 0.50.

Cubic specimens, with sides of 40 mm, were cast from the cement paste and, after 24 h of curing within the molds, the specimens were demolded and cured for 28 days in a controlled temperature and humidity environment (20° C and relative humidity above 95%). Afterwards, the cubic specimens were subjected to the monolith leaching test.