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
    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
  • Publication
    The effect of fly ash to alkaline activator ratio to the mechanical properties of stabilized lateritic soil using fly ash based geopolymer
    ( 2023-01-01)
    Muhammad Munsif Ahmad
    ;
    Khairunnisa Muhamad
    ;
    Razak R.A.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Nurul Huda Hashim
    ;
    Othman N.A.F.
    Stabilization of fill soil improve its physical and mechanical properties and led to better load carrying capacity and enable steeper temporary slope to be formed during construction period. In this study an industrial by-product, fly-ash (FA), was used as precursor to produce geopolymer as chemical stabilizer to improve the physical and mechanical properties of fill soil. Sodium silicate solution (Na2SiO3) and sodium hydroxide (NaOH) at a concentration of 15 molars were combined as the liquid alkaline activator (AA). The effect of different fly ash to alkaline activator ratio (0, 1.0, 1.5, 2.5 and 3.0) on the physical and mechanical properties of treated fill soil were measured using Atterberg limit test and unconfined compressive strength (UCS) test. All sample were tested at 1 day and 3 days of curing period under room temperature. The result indicates that the highest compressive strength is obtained with fly ash to alkaline activator ratio of 2.5 for both 1 day and 3 days of curing. In addition, the plasticity index of the treated sample for all fly ash/alkaline activator were lower than that of the untreated fill soil.
      3  13