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

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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.

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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.

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Use of Palm Kernel Shell from Agriculture Waste as Partial Replacement for Coarse Aggregate in Hot Mix Asphalt

2024-04-19 , Liyana Ahmad Sofri , Muhammad Faiz Zainal , Muhammad Munsif Ahmad , Khairunnisa Muhamad , Ahmad Faizal Mansor

Palm kernel shell (PKS) is known as a waste material that produced by oil palm factory. In this research, PKS will be used as an alternative to improve the strength and performance of hot mix asphalt (HMA). The bitumen grade of 60/70 PEN and ACW14 had been used in the research. To investigate the strength of PKS in term of designing wearing course, bitumen content of 4% to 6% and different mix design with different percentages content of PKS were provided. The total specimens prepared in this research are 45 specimens. The specific gravity of PKS was lower and showed the high capacity in water absorption compare to the natural aggregate. The increment of percentage for PKS in HMA make the strength in Marshall Specimen became decreases as stated in the result and discussion. Result of optimum bitumen content for PKS 10, PKS 30 and PKS 50 were 4.72%, 4.86% and 4.90% individually. All optimum bitumen content in this research was satisfied with JKR Standard 2008 in term of the design parameter. The specimen of PKS 10, PKS 30 was classified as heavy traffic and PKS 50 was classified as medium traffic. PKS 10 was shown as a good partial replacement for natural aggregate due to the admissibility of parameter, environmental friendly factor and cheapest in costing.

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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.

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Influence of rice husk ash (RHA) on performance of green concrete roof tile in application of green building

2020-06-10 , Khairunnisa Muhamad , Norrazman Zaiha Zainol , Norhaizura Yahya , Siti Nur Aishah Mohd Noor , Nurul Huda Hashim , Danial Zikry Shahrazi

This paper studies on the development of green concrete roof tiles by using rice husk ash (RHA) as a partial replacement of cement as a green material. Rice husk is a product of agricultural waste that can be found easily and in large quantities due to increased annual paddy production in Malaysia. Demand for cement in construction has increased over the years as a result of over dependence on the modern building materials, which are so expensive that low income earners cannot afford building houses of their own. Besides, the satisfaction of building users is closely related to thermal comfort which is a complex dynamics of temperature and humidity. In this study, cement was replaced by the RHA at 0% until 20% by weight. Roof tiles performance were assessed based on Malaysian Standard (MS) requirement comprised of transverse strength, water absorption and water permeability. Results show that up to 10% of RHA give a good performance of concrete roof tiles which comply with Malaysia Standard.

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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.

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The Influence of Cement Content to Properties of High Strength Anti Washout Concrete (HSAWC)

2024-04-19 , Khairunnisa Muhamad , Muhammad Haikal Farizad , Zarina Yahya , Liyana Ahmad Sofri

The high strength of concrete required a lot of cement content to increase its strength but not for the anti washout concrete (AWC) or underwater concrete (UWC). AWC will face another problem which is higher cement content could make the segregation to occur. This segregation process will give bad impact to the strength of the AWC. This research studied on four different cement content to examine: 450 kg/m3, 500 kg/m3, 550 kg/m3 and 600 kg/m3 towards its fresh and hardened properties of concrete. Superplasticizer is used as water reducing agent in the mix proportions to achieve high strength and self-consolidated concrete. Apart from that, there are two types of concrete samples produced, the air sampling concrete and underwater sampling concrete which have the same mix proportion. The overall results show a good correlation between the cement content in the mix and the strength of the air sampling concrete achieved. However, anti washout concrete having issues which is segregation. This segregation had affected the strength of the concrete. In conclusion, Anti washout concrete shows that optimal cement content without any viscocity modifying agent (VMA) is at 550 kg/m3

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