Browsing by Author "G/Micheal, Anteneh"

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    Suitability of Crushed Jema Sandstone for Concrete Production as Alternative to River
    (Addis Ababa University, 2017-04) G/Micheal, Anteneh; Dinku, Abebe(Professor)
    The current booming construction industries demand large reserves of construction materials and skilled workmanship. Having the luxury of abundant construction materials is one of the manifestations of a great construction industry. So far several attempts have been made to partially or fully replace river sand by other relevant fine aggregates. One of these materials were crushed Jema sandstone and this research studies its suitability as a fine aggregate. Initially, river and crushed Jema sandstone samples to be used in the concrete mixes were collected and their physical properties were studied. Twenty four different concrete mixes having eight mix proportions for both river and crushed Jema sandstone were prepared for 25, 30 and 40 MPa concrete strengths using a water cement ratio and cement contents of 0.58, 330kg/m3; 0.53, 370kg/m3; 0.45, 450kg/m3 respectively. The properties of these mixes have then been assessed both at the fresh and hardened state. In addition, chemical composition of crushed Jema sandstone was investigated. The result of silicate analysis test shows that it has a silica content greater than 94% which is desirable in sand. The results of the hardened properties of the mixes have shown that, the addition of crushed Jema sandstone resulted in increased compressive strengths. This suggests that using crushed Jema sandstone can achieve better strength of concrete. The test results showed that for all grades of concrete mix proportion, concrete with 100% crushed Jema sandstone was capable of achieving a higher compressive strength than the river sand control mix. However, as the concrete grade increased from C-25 to C-40, the relative strength gain decreased. Keywords: Crushed Jema sandstone, compressive strength, chemical composition, concrete