Assessing the Variability of Lightweight Concrete Inter- and Intra-Rater Design Parameters Concerning Aggregate Sources

This paper examines the variability of inter- and intra-rater parameters for the design of lightweightaggregate concrete. Current design codes rely on homogenizing concrete cementitious composites tomitigate the inherent variability of mixture proportions and ingredient properties. Structural lightweightconcrete specifications follow the same homogenized approach to recommend modification factors fordesign procedures using empirical data. Innovations in lightweight aggregate production and the applicationof lightweight concrete have prompted significant research developments in determining modificationfactors using accessible laboratory results like aggregate composition and equilibrium density of concrete.However, modern structural lightweight aggregate concrete applications demand incorporating additionalparameters related to the aggregate source and assessing the variability of design parameters across thebroad range of concrete members. The methodology employed in this paper endeavors to analyze variancetests on an extensive collection of empirical data. Results determine the equality of modification factors fora given aggregate source applied in different concrete elements. Further, multivariable regressions revealthe significance of relationships between aggregate and concrete properties to develop new designparameters and modification factors for structural design. Conclusions emphasize the importance of usingstatistical methods to develop reliable design procedures.