Compressive Strength Variations in Lightweight Aggregate Concrete Samples Affected by Segregation Caused by Excessive Vibration

摘要

Lightweight aggregates used in lightweight aggregate concrete (LWAC) exert an important influence on the compressive strength and elastic modulus of concrete. A good homogeneity of the material is essential in this type of concrete once a non-uniform distribution of aggregates in the mixture may strongly affect the concrete global properties, which are commonly considered as homogenous values for design purposes. LWAC, due to density differences among its components, are susceptive to segregation. The separation of the aggregates from the rest of the mixture increases the risk of cracking and areas where segregation or insufficient compaction occur are mostly the areas where the concrete failure begins. The aim of this study is analysing possible variations caused by segregation on compressive strength (f_c) along the height of cylindrical samples, comparing results of four sections extracted from samples segregated intentionally.