For structural lightweightconcrete, it is manufactured with rotary kiln that produced structurallightweight aggregate in order to provide the low density and solve the durabilityproblems for exposed structure in buildings.
Structural lightweight concretehas strengths comparable to normal weight concrete although it is typically 25to 35% lighter. It offers design flexibility and cost savings via applicationof less dead load, longer spans and smaller size structural members. Moreover,the benefits of using lightweight aggregate concrete include reduced in deadloads making savings in foundations and reinforcement, improved thermalproperties, improved fire resistance, savings in transporting and handlingpre-cast units on site and reduction in formwork and propping.The required properties ofthe 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. Forinstance, if needed of little structural requirement with high thermalinsulation properties, then light and weak aggregate can be used, but it will resultin relatively low strength concrete.With the high concern overthe excessive demand of natural aggregates, artificial lightweight aggregateproduces from waste materials as the alternative solution to conserve theenvironment. The excellent durability performance of lightweight concrete madewith expanded shale, clay, cold-bonded fly ash aggregate, slate lightweightaggregate, sintered aggregate and solid sludge give the result on ceramicnature of the aggregate and its exceptional bond to and elastic compatibilitywith the cementations matrix.
Besides, there are significant researches on theuse of fly ash production as artificial aggregate. The findings show that theartificial lightweight aggregate exhibit the almost similar physical andmechanical properties as normal concrete (Samuel et al., 2011).