Use of gyratory compaction for investigation of building materials
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Helsinki University of Technology |
Diplomityö
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Date
2008
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Tietekniikka
Mcode
Yhd-10
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Language
en
Pages
80 (+70)
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Abstract
A variety of test series were conducted to analyze the application of a gyratory compaction testing for the building materials. Prior research has indicated that the state-of-the art gyratory compactors such as Intensive Compaction Tester (ICT) could be employed in improved characterization of granular construction materials. The range of such research has mostly been limited to assessment of Hot-Mix Asphalt (HMA) properties, although drycast (no-slump) concrete and unbound aggregate mixes have also been analyzed through gyratory compaction. In order to assess the full scale investigative potential of the ICT, a framework of supporting tests were devised around the gyratory compaction. Various combinations of output from such tests along with parameters measured by the ICT enabled a wide range of analysis. Four test series (A to D) were completed in this research. The objective of the Series A research was to differentiate between drycast concrete mixing strategies based on the compactibility of the resulting product. Using supporting output from the semi adiabatic calorimetry measurements, the trends indicating advantage of high speed mixing and dry mixing were established. The influence of extra paste volume with respect to available void space on compactibility of drycast concrete was investigated in Series B. Shear development data obtained from the ICT device enabled the determination of limits at which pore pressure development occurs. To further analyze the trends obtained in Series B, a series of packing tests were done on the unbound component of the concrete mixes in Series C. The rate of stress development during gyratory compaction was seen to be governed by the aggregate skeleton of the mix irrespective of the paste content. The application of the ICT and supporting framework of tests was extended in Series D to evaluate construction material based on dilative potential. Unbound asphalt mixture aggregate combinations based on specified gradations used in practice were tested. Based on the established trends, a number of further studies can be recommended. The findings of Series A could be confirmed by similar tests on other concrete mixtures containing cementitious additives and admixtures. The pore pressure development scenario and the dominant role of aggregate skeleton established in Series B & C could prove to be of interest if established in case of HMA. The dilation measurements exercised in Series D could serve as a template for the performance based material selection.Description
Supervisor
Pellinen, TerhiThesis advisor
Nordenswan, ErikKeywords
compactibility, dilation, gyratory compaction, blending technique, paste volume, pore pressure, mixing