Khairunnisa Muhamad
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Preferred name
Khairunnisa Muhamad
Official Name
Muhamad, Khairunnisa
Alternative Name
Khairunnisa, M.
Muhamad, K.
Main Affiliation
Scopus Author ID
55779052600
Researcher ID
N-4546-2017

Research Output
Now showing 1 - 3 of 3
  • Publication
    A Review on the Concrete Durability Exposed to Different Wet-Dry Cycles Conditions
    ( 2024-04-19)
    Zarina Yahya
    ;
    Rafiza Abd Razak
    ;
    Khairunnisa Muhamad
    Concrete structure is prone to corrosion and weathering when built near marine environment. The greater damage on the concrete can be observed when it involves wet-dry action such as tidal waves combine with the existence of aggressive ions such as sulphate and chloride in seawater. The objective of this study is to review on the mechanism of sulphate, chloride attack toward concrete, parameters that influence the wet-dry action and identify the overview of research trends. The mechanism of sulphate and chloride attack during wet-dry action had reciprocal inhibiting effect on concrete and the penetration level for each ion also vary. The physical and mechanical damage of concrete exposed to wet-dry action also influence by wet-dry ratio, number of cycles and temperature during drying process. The main compound detected during exposure period are Friedel salt, ettringite, mirabilite and thenardite which can cause concrete delamination and spalling.
  • Publication
    Paraffin as a Phase Change Material in Concrete for Enhancing Thermal Energy Storage
    ( 2020-03-18)
    Rafiza Abd Razak
    ;
    Khang Zhe A.C.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Zarina Yahya
    ;
    Junaidi S.
    ;
    Khairunnisa Muhamad
    ;
    Nurul Aida Mohd Mortar
    Phase change material (PCM) for thermal energy storage (TES) is the material that can absorb energy during heating process as phase change takes place and release energy to environment during cooling process. Nowadays, energy consumption trends in construction building show a significant increase. It is important for reducing energy consumption in building by decreasing the energy demand and providing thermal human comfort inside the building. The objectives of this research are to determine the optimum percentage of PCM in concrete affected by time to achieve high thermal storage performance and evaluate the mechanical properties in different percentage of PCM concrete. Various percentage of 0%, 5%, 10% 15% and 20% of PCM concrete added with Ground Granular Blast Slag (GGBS) as filler were prepared and tested after 7 and 28 days of curing process. The result shows the thermal storage energy effective when integration with PCM in concrete. Besides, the compressive strength, water absorption and density measurement decrease with increasing amount of PCM. In conclusion, 5% of PCM with 30% GGBS added in concrete resulted in better thermal energy storage and compressive strength compared to other percentages of PCM concrete samples.
      3  9
  • Publication
    EFFECT OF GROUND GRANULATED BLAST SLAG (GGBS) TO THE BONDING STRENGTH OF GEOPOLYMER MORTAR AS REPAIRING MATERIAL
    ( 2020-08-28)
    Rafiza Abd Razak
    ;
    Zarina Yahya
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Subaer S.
    ;
    Khairunnisa Muhamad
    ;
    Ahmad Zailani, Warid Wazien
    ;
    Teng, T. Siang
    The bonding strength of geopolymer mortar is very important for binding the old concrete with the latest concrete when act as repair material. The present study is aim to determine the best ratio between GGBS and fly ash in order to find the optimum bond strength under ambient temperature. There are five different ratios of GGBS to fly ash that had been tested in this research which are GGBS: FA= 10:90, 20:80, 30:70, 40:60, and 50:50. The different mixture of GGBS and fly ash is added with the alkaline solution (12M of sodium hydroxide and sodium silicate) and sand which have been mixed then rapped cured under ambient temperature. Once the mixing is done completely, pour the mixture into the metal mold and attach with the OPC concrete substrate. The bonding strength of this research were tested by using slant shear test in 7 days, 28 days and 60 days of curing. From the result tested, GGBS: FA= 30:70 could concluded as the best ratio for presenting the optimum bonding strength in this research since the bond strength for GGBS: FA=30:70 had obtain optimum strength under long curing time (9 MPa in 28 days cured and 10.6 MPa in 60 days cured). The maximum compressive strength of 46.4 MPa was observed at geopolymer mortar with GGBS: FA = 30:70. There are many factors affecting the bond strength of geopolymer which are slow setting time of fly ash and GGBS, curing temperature, size of GGBS and also the mixture proportion. The present study had concluded that GGBS: FA= 30:70 in geopolymer mortar are the best for presenting the bond strength.
      4  7