Khairel Rafezi Ahmad
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Preferred name
Khairel Rafezi Ahmad
Official Name
Ahmad, Khairel Rafezi
Alternative Name
Ahmad, Khairel R.
Ahmad, K. R.
Rafezi Ahmad, Khairel
Ahmad, Khairel Rafiez
Ahmad, Khairul R.
Khairel, R. A.
Rafezi, Khairel
Ahmad, Khairel Refazie
Ahmad, Khaireel Rafezi
Main Affiliation
Scopus Author ID
43260917000
Researcher ID
AAK-8057-2020

Research Output

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  • Publication
    Recycled Incineration Bottom Ash and Metakaolin as Sustainable Materials for Cement Replacement in Cementitious Composites
    ( 2023-01-01)
    Roshazita Che Amat
    ;
    Syakirah Afiza Mohammed
    ;
    Norlia Mohamad Ibrahim
    ;
    Nur Liza Rahim
    ;
    Khairel Rafezi Ahmad
    ;
    Raischi M.
    Study was related to the influence of the concrete properties by using different percentages of metakaolin and fixed percent of incineration bottom ash to partially replace the cement. Cement is a well-known building material and used for the construction in the world. Moreover, the used of metakaolin (MK) and incineration bottom ash (IBA) in this research would give significance to our environment as it can reduce the usage of cement in concrete. By using bottom ash, it could reduce the land filling space. The X-Ray Fluorescence (XRF) test was used to determine the chemical composition of IBA and MK. Four series of concrete have been examined, including control, IBA and MK were used as partial replacement for cement at 10%IBA + 10%MK, 10%IBA + 15%MK and 10%IBA + 20%MK of concrete mixes by volume. The curing period for the samples is 7 days and 28 days. To determine the properties of concrete, the tests such as slump test, density test, water absorption test, pulse velocity test, rebound hammer test and compression test were performed. The results proved that the strength development of 10%IBA + 10%MK concrete sample shows the highest compressive strength after 28 days of curing.
      2
  • Publication
    Effects of metakoalin on municipal solid waste incineration (Mswi) bottom ash-cement composite
    ( 2020-01-01)
    Roshazita Che Amat
    ;
    Khairul Nizar Ismail
    ;
    Khairel Rafezi Ahmad
    ;
    Norlia Mohamad Ibrahim
    Municipal solid waste incinerators (MSWI) produce by products which can be classified as bottom and fly ashes. The bottom ash (BA) accounts for 85-90% of solid product resulting from municipal solid waste combustion. The objective of this study was to assess the feasibility of municipal solid waste incineration bottom ash as a supplementary cementations material for the preparation of blended cement. The used of bottom ash as a research material is because of substances contained in bottom ash which is almost same with cement. X-Ray Fluorescence (XRF) spectroscopy analysis was used to determine chemical compositions of the BA and metakoalin (MK) used in this study. Five series of concrete mix design had been examined which contained different percentage of bottom ash and metakaolin as partial replacement for cement in concrete mixes by volume. A few test such as workability, water absorption, and compression test were carried out to investigate properties of grade 20 concrete incorporating bottom ash and metakaolin. The concrete cubes were tested at age of 7 and 28 days to study the development its compressive strength. Concrete mix design with 10% BA and 10% MK shows the highest strength of 32.9 MPa and surpassed strength 20 MPa. Bottom ash was found to have some reactivity, but without greatly affecting the hydration process of Ordinary Portland cement (OPC) at 10% replacement with 10% metakaolin is required to be used in the production of concrete in order to improve strength.
      17  3