The overall solid packing see mix design method of Brouwers and Radix was modified by developing an optimisation tool, facilitating the proportioning normal weight SCCs (NWSCCs) and L WSCCs. The method comprised two concepts: filling the voids within the loosely packed aggregate fraction with appropriate paste and comparing the overall particle size distribution (PSD) of solids in the mix with the model PSD. To implement this method, the influence of supplementary cementitious materials (SCMs), fillers and chemical admixtures on the paste properties was investigated; moreover, physical properties and packing of normal and lightweight aggregates (L W As) were studied. The influence of two L WAs, three superplasticisers and three SCMs/fillers on the fresh properties and compressive strength of LWSCCs was evaluated, followed by a detailed study on L WAs and SCMs/fillers effect on engineering and durability properties of L WSCCs. The proposed mix design modification yielded highly flowable, strong and durable L WSCCs for structural precast applications. Successful LWSCCs required carefully optimised paste composition and paste/aggregate content. L W As water absorption characteristics and cement-superplasticiser compatibility strongly influenced workability and workability retention of LWSCCs. The effect of aggregate composition and aggregate/paste content on fresh, hardened and durability properties of structural NWSCCs was studied. The proposed mix design allowed manufacturing NWSCCs with moderate workability, high strength and paste content lower than typically reported. Most of NWSCCs properties correlated with the average spacing between the aggregate particles, allowing for engineering of NWSCC properties by its adjustment.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602356 |
| Date | January 2013 |
| Creators | Kwasny, Jacek |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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