Pore characterization of manufactured aggregates: recycled concrete aggregates and lightweight aggregates

Accurate characterization of aggregates plays an important role in mixture proportioning of concrete mixes. Decisions made during the concrete design phase in terms of characterization techniques adopted for quantification of specific gravity or water absorption affect the development of fresh properties during the construction phase as well as impacting the long term performance of concrete. Manufactured aggregates such as recycled concrete aggregates (RCA) and lightweight aggregate (LWA) are more absorptive than natural aggregate. Due to the thrust on construction of sustainable structures usage of LWA and RCA has increased significantly in the last decade. In this study, standard ASTM techniques adopted for porosity and specific gravity measurement of aggregates were compared with automated testing equipment such as the helium pycnometer and the envelope density analyzer. Porosity of different aggregates obtained using different test methods was compared with image analysis. Pore diameter characterization of different RCA was conducted using image analysis.