Selfweight of foamed lightweight concrete is
lighter than normal concrete nor brick. Application of
foamed lightweight concrete on the wall of hight rise
building will decrease structural load. With lower
structural load the structural dimension will
significantly decrease and also construction cost.
Utilization of fly ash waste as an added material of
sand on lightweight concrete will reduce the negative
impact of the environment and increase the strength
of concrete. This study will examine the physical and
mechanical characteristics of lightweight foam
concrete for wall materials referring to the
Indonesian National Standard (SNI). Comparison
used 1 cement : 1 aggregate. Aggregates consist of
sand and fly ash added material 0%, 15%, 30%, 45%,
60% and 75% by weight of sand. Cement water factor
0.35, and foam 30%, 40% and 50% of lightweight
concrete volume. Cylinder sample dimension are 75
mm in diameters and 150 mm height. The number of
test samples of compressive strength, water
absorption, and specific gravity of 170 units. The
results of research is density of the foamed
lightweight concrete of 868.4 - 1582.4 kg / m3
fulfilled the criteria as lightweight concrete. The
novelty of this research is the optimal compressive
strength of various percentages of foam achieved at
45% fly ash. Foam with 30% has a compressive
strength of 12.52 MPa fulfill the quality of I, foam
with 40% has a compressive strength of 6.75 MPa
fulfill the quality of III and foam with 50% has a
compressive strength of 1.66 MPa does not fulfill the
quality of SNI. The lowest water absorption is 5.12%,
8.35% and 15.97% fulfill the quality of I SNI at the
45% fly ash. Self weight of 1 m 2 wall of foamed
lightweight concrete with a thickness of 120 mm
25.88% lighter than a half-brick brick wall with the
same area.