• The influence of vibration time and sand type on the compressive strength of sandcrete hollow blocks

      Alutu, Okey Edwin; Omoregie, Alohan; University of Benin (Trans Tech Publications, 2009-02-20)
      The purpose of this study is to see if varying the vibration time and sand type during moulding of blocks would affect the strength of the blocks. To this end, seven types of sands: Okhuahie and Ovia river sands; Okhuahie, Ovia, Ikpoba flood and Okhoro erosion sands were collected for the study. A total of 315 blocks each in 150mm and 225mm sizes with cement to sand ratios of 1:6 were made using the seven brands of sand. The blocks were vibrated for 10, 15, 20, 25, and 30 seconds and tested for compressive strength at 7 days, 14 days and 28 days respectively. The result showed that the relationship between compressive strength of the blocks and the vibration time for various sand types was linear up to vibration time of 30 secs. The sand type also influenced the strength of the blocks as Okhuahie river sand gave the highest compressive strength followed by Ovia river sand and the least was Okhoro erosion sand. At least 52% increase in compressive strength of 150mm and 225mm sandcrete blocks were achieved by raising the vibration time from 15 seconds to 25 seconds in the seven types of sand and 100% increase was achieved by raising the vibration time from 15 to 30 seconds.
    • Mechanics and materials in the design of a buckling diaphragm wave energy converter

      Le, Huirong; Collins, Keri M.; Greaves, Deborah M.; Bellamy, Neil; University of Plymouth (2015-04-25)