Browsing by Author "Ajagbe, W. O."

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    Effects of Copper (II) Nitrate Trihydrate Admixture on some Fresh and Hardened Properties of Concrete
    (2018) Ajagbe, W. O.; Ganiyu A. A; Akinkunmi J. T.
    The use of admixtures to improve specific properties of concrete has gained popularity in the construction industry in recent years. Fungicidal admixtures are used to control bacterial and fungal growth on or in concrete. The effects of Copper (II) Nitrate Trihydrate [Cu(NO3)2.3H2O] admixture on the workability and strength of concrete was investigated in this research. Concrete cubes of 150 x 150 x 150mm were cast with different proportions, 0 - 4% of Cu(NO3)2.3H2O by mass of cement. Slump and compressive strength tests were conducted. The result shows that the slump value increases with increase in percentage of Cu(NO3)2.3H2O; the concrete workability is medium up to 2.5% of Cu(NO3)2.3H2O inclusion, beyond which the concrete is highly workable. Furthermore, the compressive strength reduces with increase in the percentage of Cu(NO3)2.3H2O; above 0.5% of Cu(NO3)2.3H2O inclusion, the value of the compressive strength obtained was below the target design value of 20 N/mm2. In essence, the improvements in the workability adversely affects the strength of the concrete.
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    Suitability of Nigeria Portland-limestone cement grades for building's concrete structural members in various exposure classes
    (Civil Engineering Department, University of Ibadan, Ibadan, Nigeria, 2015-07) Adewole, K. K.; Ajagbe, W. O.; Akintayo F.O.
    This work investigates the suitability of the Nigerian Portland-limestone cement grades 32.5 and 42.5 for the construction of building structural members in various exposure condition/classes. The investigation was conducted by comparing the 25MPa, 27MPa and 30MPa average cube compressive strengths and the 30MPa, 30Mpa and 31MPa average cube compressive strengths of 1:2:4, 1:1.5:3 and 1:1:2 concretes produced with Portland-limestone cement grades 32.5 and 42.5 respectively with the minimum durability concrete strength requirements for building structural members in Eurocode 2 exposure classes that are obtainable in Nigeria. Investigation revealed that Portland-limestone cement grades 32.5 is only suitable for the construction of superstructure members inside low humidity buildings (class XC1) and is not suitable for the construction of buried building foundations and external building superstructure members. Portland-limestone cement grade 42.5 is only suitable for the construction of superstructure members in exposure classes XC1 and XC2 (building superstructure members subject to long-term water contact) and building foundations buried in non-aggressive natural soils and groundwater. Both cement grades 32.5 and 42.5 are not suitable for the construction of building external superstructure members sheltered from/exposed to rain and subject to high humidity (class XC3) and/or cyclic wet and dry condition (class XC4). Both cement grades are also not suitable for the construction of building foundations buried in aggressive natural soils and groundwater (exposure classes XA1, XA2 and XA3) and building superstructure members in industrial and coastal areas with airborne, waterborne and/or seawater-borne chlorides (exposure classes XD1, XD2, XD3 and XS1).