This paper describes in-house tests and analyses developing during work on the tailoring of concrete technology. Computerized particle packing models are used to analyze the available aggregate sources in order to achieve the highest degree of aggregate packing while observing, where relevant, the needed adjustments to accommodate air-entrainment. Rheological studies are used to optimize the choice and dosage of chemical admixtures using both instrumentation which measures on pastes and on mortar as well as equipment which measures the rheological behaviour of fresh concrete. Using a specially designed controlled compaction instrument the compaction of fresh concrete, in particular low-slump concrete, can be simulated. For instance, if a given concrete composition using a particular piece of construction equipment can be compacted to a certain density, the compactive effort can be modelled. On this basis it is possible rationally to test a range of candidate mix designs in the laboratory at low cost rather than in full scale at higher cost. Where required, as for instance for slip-formed median barriers, the form stability of the freshly molded concrete is measured using equipment developed based on experience from the porcelain industry. Only the abstract is published here.
Abstract