Properties of metakaolin geopolymer hardened paste prepared by high-pressure compaction

The paper presents the results of the study on the effects of the combination of the low liquid/solid (l/s) ratio and pressure compaction of the fresh pastes on the properties of the hardened metakaolin geopolymer paste. It is well known that the combination gives the possibility to prepare cement composites resulting in the excellent engineering properties. The results obtained shown the high dense nano- or near-nano-pore structure with high degree of its homogeneity and high strength of metakaolin geopolymer hardened paste prepared under the use of very low l/s ratio and pressure compaction.Two factors were found responsible for the high positive effects:(i)Mechanical effect of the densifying of the starting mixture and the decrease of the initial porosity due to action of the applied pressure compaction.(ii)The well known very positive effect of the l/s ratio decrease on the rate and level of the development of the properties of cement composites.

Research highlights
► The paper presents the results of the study on the effects of the combination of the low liquid/solid (l/s) ratio and pressure compaction of the fresh pastes.
► The results obtained shown the high dense nano- or near-nano-pore structure with high degree of homogeneity and high strength of metakaolin geopolymer hardened paste.
► Two factors were found responsible for the high positive effects: (i) Mechanical effect of the densifying of the starting mixture and the decrease of the initial porosity due to pressure compaction. (ii) The well known very positive effect of the low l/s ratio on the level of the properties of cement composites.