54
H. Asrah et al.
silicate hydrate (CSH) gel compound for strength development process (Karim et al.
2011). Instead of having pozzolanic properties, POFA also acts as microfiller to fill
voids within the concrete microstructure when ground to a finer size (Asrah et al.
2015). In raw condition, unground POFA usually has larger sizes and known as
porous material. However, ultrafine POFA has better quality and produced concrete
with higher engineering properties compared to the unground POFA when used as
cement replacement. These properties have improved the role of POFA in making
strong and durable construction materials.
2 Materials and Methods
The materials used in this study include the Ordinary Portland Cement (OPC), river
sand, clay soil, water and POFA. The clay soil was extracted from UMS site area and
used to produce the control brick samples. Meanwhile, POFA was collected from
Lumadan Palm Oil Mill in Beaufort, Sabah. The river sand has a specific gravity
of 2.72, which 90% passing through the 600 µm sieve. Two (2) types of POFA
were used in this research; the unground POFA and ultrafine POFA. Table 1 shows
the mix proportions of the compressed brick samples using unground and ultrafine
POFA at various amounts. The water to POFA and cement ratio is fixed at 0.25.
In the compressed brick sample production, the prescribed quantity of POFA and
cement were mixed thoroughly, and water was added gradually until the mixture is
consistent in colour. The mixture was then poured into 50 × 50 × 50 mm moulds
and compressed using the compression machine at 43 kN pressure. The sample was
demoulded and left for 24 h with cover to prevent from evaporation. The curing was
only commenced on the second day after casting by sprinkling of water for 12 and
24 days.
Table 1 Mix proportion for
compressed brick
Mix
Cement (g)
Sand (g)
POFA (g)
(Soil) a
Control
250
125
(750) a
UF-10
250
125
250
UF-20
250
125
500
UF-30
250
125
750
UF-40
250
125
1000
UG-10
250
125
250
UG-20
250
125
500
UG-30
250
125
750
UG-40
250
125
1000
a Note: UF–ultrafine POFA
UG–unground POFA
H. Asrah et al.
silicate hydrate (CSH) gel compound for strength development process (Karim et al.
2011). Instead of having pozzolanic properties, POFA also acts as microfiller to fill
voids within the concrete microstructure when ground to a finer size (Asrah et al.
2015). In raw condition, unground POFA usually has larger sizes and known as
porous material. However, ultrafine POFA has better quality and produced concrete
with higher engineering properties compared to the unground POFA when used as
cement replacement. These properties have improved the role of POFA in making
strong and durable construction materials.
2 Materials and Methods
The materials used in this study include the Ordinary Portland Cement (OPC), river
sand, clay soil, water and POFA. The clay soil was extracted from UMS site area and
used to produce the control brick samples. Meanwhile, POFA was collected from
Lumadan Palm Oil Mill in Beaufort, Sabah. The river sand has a specific gravity
of 2.72, which 90% passing through the 600 µm sieve. Two (2) types of POFA
were used in this research; the unground POFA and ultrafine POFA. Table 1 shows
the mix proportions of the compressed brick samples using unground and ultrafine
POFA at various amounts. The water to POFA and cement ratio is fixed at 0.25.
In the compressed brick sample production, the prescribed quantity of POFA and
cement were mixed thoroughly, and water was added gradually until the mixture is
consistent in colour. The mixture was then poured into 50 × 50 × 50 mm moulds
and compressed using the compression machine at 43 kN pressure. The sample was
demoulded and left for 24 h with cover to prevent from evaporation. The curing was
only commenced on the second day after casting by sprinkling of water for 12 and
24 days.
Table 1 Mix proportion for
compressed brick
Mix
Cement (g)
Sand (g)
POFA (g)
(Soil) a
Control
250
125
(750) a
UF-10
250
125
250
UF-20
250
125
500
UF-30
250
125
750
UF-40
250
125
1000
UG-10
250
125
250
UG-20
250
125
500
UG-30
250
125
750
UG-40
250
125
1000
a Note: UF–ultrafine POFA
UG–unground POFA