Physical and Microstructural Properties of Construction and Demolition Waste Based Masonry Units

The aim of this study was to employ crushed Demolished Brick Masonry, a variety of Construction and Demolition Waste as a replacement for conventional construction materials (natural soil and aggregates) primarily in the production of three types of masonry units, namely Solid Concrete Blocks, Stabilized Adobe Blocks and Stabilized Mud Concrete Blocks. In addition Controlled Low Strength Material was also studied. Long term strength of these specimens was studied at different ages to determine their performance. Scanning Electron Microscopy in addition to Energy Dispersive Spectroscopy and X-Ray Diffraction were used to study the microstructure and identify the phases present in it. SEM revealed the presence of Calcium-Silicate-Hydrate Crystals and voids in the microstructure. In Solid Concrete Blocks the distribution of C-S-H was sparse compared to commercial concrete blocks due to the lower cement content employed. Significant differences could not be observed in the morphology of C-S-H among different proportions of SAB studied. The microstructure of Controlled Low Strength Material was quite similar to that of Stabilized Adobe. Stabilized Mud Concrete Blocks had a particularly dense network of C-S-H compared to the other types of units. XRD indicated the presence of Anorthite, which was highest in Stabilized Mud Concrete Blocks and lowest in Stabilized Adobe Blocks.