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The influence of Sodium Hydroxide concentration on physical properties and strength development of high calcium fly ash based geopolymer as pavement base materials

2020 , Liyana Ahmad Sofri , Mohd. Mustafa Al Bakri Abdullah , Mohd Rosli Mohd Hasan , Yue Yuan H.

This paper deals with the development of high calcium fly ash based geopolymers. Geopolymer paste was prepared from fly ash alkaline activator solutions using various mix design including molarity of sodium hydroxide used (6-14M) with solid-to-liquid ratio (1.0-3.0) and the sample were curing at ambient temperature. In this paper, flow value, setting time and unconfined compressive strength of high calcium fly ash based geopolymer paste was carried out using flow table equipment, Vicat’s apparatus and compression testing machine to measure the properties caused by high calcium fly ash. It was found that solid to liquid ratio of 2.0 and NaOH molarity of 12M was the best mix design to be applied due to its maximum unconfined compressive strength achieved (up to 19MPa at 28 days) as well as its flow ability of the fresh paste which shown better result compared to other mix designs. High calcium was also found to result in higher strength.

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Unconfined compressive strength of various types of pavement base material: a review

2020 , Liyana Ahmad Sofri , Mohd Rosli Mohd Hasan , Mohd. Mustafa Al Bakri Abdullah , Yue Yuan H. , Acep Hidayat , Muhammad Faheem Mohd. Tahir

In the highway construction industry especially for pavement base material, cement treated material is a conventional method that had been applied. Other than that, there is various types of base can be used such as cement kiln dust, reclaimed asphalt pavement, fly ash, and mine tailings. The usage of this various material can improve the unconfined compressive strength (UCS) of the base it terms of the strength. It was found that the UCS is the important properties to indicate the durability of the base. This paper summarized the material and the result of various types of base materials.

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Mechanical performance of Fly Ash based Geopolymer (FAG) as road base stabilizer

2022 , Liyana Ahmad Sofri , Mohd. Mustafa Al Bakri Abdullah , Andrei Victor Sandu , Thanongsak Imjai , Petrica Vizureanu , Mohd Rosli Mohd Hasan , Mohammad Almadani , Ikmal Hakem Ab Aziz , Farahiyah Abdul Rahman

This study examines the strength development of fly ash-based geopolymer (FAG) as a stabilizer for road base material for pavement construction. In the last decade, there has been a rapid development of conventionally treated bases, such as cement-treated bases. However, a major problem with this kind of application is the shrinkage cracking in cement-treated bases that may result in the reflection cracks on the asphalt pavement surface. This study explores the effects of FAG on base layer properties using mechanistic laboratory evaluation and its practicability in pavement base layers. The investigated properties are flexural strength (FS), unconfined compressive strength (UCS), shrinkage, and resilient modulus (RM), as well as indirect tensile strength (ITS). The findings showed that the mechanical properties of the mixture enhanced when FAG was added to 80–85% of crushed aggregate, with the UCS being shown to be a crucial quality parameter. The effectiveness of FAG base material can have an impact on the flexible pavements’ overall performance since the base course stiffness directly depends on the base material properties. As a stabilizing agent for flexible pavement applications, the FAG-stabilized base appeared promising, predicated on test outcomes.