For structural lightweight
concrete, it is manufactured with rotary kiln that produced structural
lightweight aggregate in order to provide the low density and solve the durability
problems for exposed structure in buildings. Structural lightweight concrete
has strengths comparable to normal weight concrete although it is typically 25
to 35% lighter. It offers design flexibility and cost savings via application
of less dead load, longer spans and smaller size structural members. Moreover,
the benefits of using lightweight aggregate concrete include reduced in dead
loads making savings in foundations and reinforcement, improved thermal
properties, improved fire resistance, savings in transporting and handling
pre-cast units on site and reduction in formwork and propping.
The required properties of
the lightweight concrete depend on the function and structure of the building.
There will have a bearing on the best type of lightweight aggregate to use. For
instance, if needed of little structural requirement with high thermal
insulation properties, then light and weak aggregate can be used, but it will result
in relatively low strength concrete.
With the high concern over
the excessive demand of natural aggregates, artificial lightweight aggregate
produces from waste materials as the alternative solution to conserve the
environment. The excellent durability performance of lightweight concrete made
with expanded shale, clay, cold-bonded fly ash aggregate, slate lightweight
aggregate, sintered aggregate and solid sludge give the result on ceramic
nature of the aggregate and its exceptional bond to and elastic compatibility
with the cementations matrix. Besides, there are significant researches on the
use of fly ash production as artificial aggregate. The findings show that the
artificial lightweight aggregate exhibit the almost similar physical and
mechanical properties as normal concrete (Samuel et al., 2011).