| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程技術學系 === 83 === This study bases on the proportional method of th least-void
ratio concept to mix the high-performance concrete. The effects
of coarse aggregate properties from four defferent kinds on the
strengths of concrete at various ages are investigated. Under
same proportion, the relations between different aggregates,
aggregate gradings, aggregate sizes and uniaxial compressive
strength of concrete specimens are presented. The influence of
the basic characteristics for different aggregates on the
stress-strain curve, elastic modulus, flexural strength and
splitting tensile strength of concrete specimens are discussed.
The bonding state between mortar and different aggregates, and
the surface condition of aggregates are also examined by SEM.
Experimental results indicate that the compressive strengths of
types A, B, C, and D aggregates are 93.55, 71.68, 69.96 and
42.37 Mpa respectively; the splitting tensile strengths are
3.72, 3.36, 2.72 and 2.21 Mpa respectively; the elastic moduli
are in the range of 15.96 to 23.55 GPa respectively. Under the
condition of same aggregate but having uniform aggregate sizes,
aggregates with the higher strength do not mecessarily have a
higher compressive strength of the corresponding concrete
specimens. Same aggregates but with different grading have
little effects on the elastic modulus of concrete. Aggregates
with better engineering properties always have denser interior
constitution, better workability and higher pulse speed of
sound.
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