STUDY OF THE ELASTIC BEHAVIOR OF SYNTHETIC LIGHTWEIGHT AGGREGATES (SLAs)
lightweight aggregates (SLAs), composed of coal fly ash and recycled plastics, represent
a resilient construction material that could be a key aspect to future sustainable
development. This research focuses on a prediction of the elastic modulus of SLA,
assumed as a homogenous and isotropic composite of particulates of high carbon fly ash
(HCFA) and a matrix of plastics ... read more(HDPE, LDPE, PS and mixture of plastics), with the
emphasis on SLAs made of HCFA and PS. The elastic moduli of SLA with variable fly ash
volume fractions are predicted based on finite element analyses (FEA) performed using
the computer programs ABAQUS and PLAXIS. The effect of interface friction (roughness)
between phases and other computation parameters; e.g., loading strain, stiffness of
component, element type and boundary conditions, are included in these analyses.
Analytical models and laboratory tests provide a baseline for comparison. Overall,
results indicate ABAQUS generates elastic moduli closer to those predicted by
well-established analytical models than moduli predicted from PLAXIS, especially for
SLAs with lower fly ash content. In addition, an increase in roughness, loading strain
indicated increase of SLAs stiffness, especially as fly ash content increases. The
elastic moduli obtained from unconfined compression generally showed less elastic moduli
than those obtained from analytical and ABAQUS 3D predictions. This may be caused by
possible existence of pre-failure surface in specimen and the directly interaction
between HCFA particles. Recommendations for the future work include laboratory
measurements of SLAs moduli and FEM modeling that considers various sizes and random
distribution of HCFA particles in SLAs.
Thesis (Ph.D.)--Tufts University, 2016.
Submitted to the Dept. of Civil Engineering.
Advisor: chris swan.
Committee: qiaobing xu, anil saigal, and robert viesca.
Keyword: Engineering.read less