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Properties and Morphology of Fly Ash Based Alkali Activated Material (AAM) Paste Under Steam Curing Condition

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Razak R. A. , Izman S. N. S. S. , Abdullah M. M. A. B. , Yahya Z. , Abdullah A. , Mohamed R.

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tom Vol. 68, iss. 2

785--789

EN

This paper details the properties, microstructures, and morphologies of the fly ash-based alkali-activated material (AAM), also known as geopolymers, under various steam curing temperatures. The steam curing temperature result in subsequent high strengths relative to average curing temperatures. However, detailed studies involving the use of steam curing for AAM remain scarce. The AAM paste was prepared by mixing fly ash with an alkali activator consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). The sample was steam cured at 50°C, 60°C, 70°C, and 80°C, and the fresh paste was tested for its setting time. The sample also prepared for compressive strength, density, and water absorption testings. It was observed that the fastest time for the fly ash geopolymer to start hardening was at 80°C at only 10 minutes due to the elevated temperature quickening the hydration of the paste. The compressive strength of the AAM increased with increasing curing time from 3 days to 28 days. The AAM’s highest compressive strength was 61 MPa when the sample was steam cured at 50°C for 28 days. The density of AAM was determined to be ~2122 2187 kg/m3, while its water absorption was ~6.72-8.82%. The phase analyses showed the presence of quartz, srebrodolskite, fayalite, and hematite, which indirectly confirms Fe and Ca’s role in the hydration of AAM. The morphology of AAM steam-cured at 50°C showed small amounts of unreacted fly ash and a denser matrix, which resulted in high compressive strength.

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Properties of stone mastic asphalt incorporating nano titanium as binder’s modifier

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Zali N. S. S. M. , Masri K. A. , Jaya R. P. , Abdullah M. M. A. B. , Hasan M. , Hasan M. R. M. , Jeż B. , Nabiałek M. , Sroka M. , Pietrusiewicz P.

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tom Vol. 68, nr 1

653--666

EN

Stone mastic asphalt is a gap-graded mix and is usually related to its high bitumen content and its skeleton-like constitution. Although famous for its durability, high resistance to fatigue and rutting, issues such as bleeding and premature aging do occur in the mix since it has a high bitumen content and voids due to its gap-graded structure. In order to encounter these problems from affecting the mix, some instances such as adding additives, rejuvenators and stabilizers into the mixture has been implemented. Nowadays, nano materials are being used in the asphalt mixtures and nano titanium is being introduced as a modifier to the asphalt binder in order to improve the mechanical properties of the stone mastic asphalt mix. The related tests done in order to access the improvement are resilient modulus, dynamic creep, moisture susceptibility and binder drain down. The content of nano titanium used in this research are 1%, 2%, 3%, 4% and 5%. This study is done to assess the mechanical performance of stone mastic asphalt with nano titanium modified binder.

3

The impact of microwave treatment on the chemical properties of sewerage sludge

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Ing D. S. , Jaya R. P. , Ho C. M. , Chin S. C. , Nabiałek M. , Abdullah M. M. A. B. , Garus S. , Śliwa A.

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tom Vol. 68, nr 1

365--377

EN

Due to urbanization, the population in the major cities in Malaysia is approximately 72.8% of its total population. The increase of population density has directly increased the amount of sewerage sludge waste that poses threat to the environment. In line with the green initiatives, alternative method to develop good quality concrete material from sewerage sludge waste can be further explored. Traditionally, sewerage sludge waste is processed using incinerator that require high energy and it is time consuming. In this study, microwave heating which require less energy consumption and less time consuming is used for sewerage sludge preparation. Prior to heating process, sewerage sludge waste is over dried at 105°C for 24 hours. Three types of microwave heating namely medium heating, medium high heating and high heating has been used. The chemical and physical properties microwaved sewerage sludge ash (MSSA) was tested using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Based on the result, the recommended temperature for the MSSA production for the concrete is High Mode Temperature. This is due to the result of MSSA for X-Ray Fluorescent test as its shows the highest in the content for pozzolanic element which are SiO2 and Fe2O3 that produce after the microwave burning process. The mineralogical composition and the crystalline phase of the High temperature MSSA due to X-Ray Diffraction test also shows high content of SiO2 as the major component as it is good for pozzolanic reaction in concrete. From the Scanning Electron Microscope test, it is observed that particle of High heated MSSA are slightly smaller than other temperature. Also, the densification occurs at High temperature MSSA. Hence, the optimal burning temperature mode for MSSA is High Mode temperature.

4

Compressive strength and durability of foamed concrete incorporating Processed Spent Bleaching Earth

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Othman R. , Muthusamy K. , Sulaiman M. A. , Duraisamy Y. , Jaya R. P. , Wei C. B. , Abdullah M. M. A. B. , Mangi S. A. , Nabiałek M. , Śliwa A.

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tom Vol. 68, nr 2

627--643

EN

Foamed concrete incorporating processed spent bleaching earth (PSBE) produces environmentally friendly foamed concrete. Compressive strength, porosity, and rapid chloride penetration tests were performed to investigate the potential application for building material due to its low density and porous concrete. Laboratory results show that 30% PSBE as cement replacement in foamed concrete produced higher compressive strength. Meanwhile, the porosity of the specimen produced by 30% PSBE was 45% lower than control foamed concrete. The porosity of foamed concrete incorporating PSBE decreases due to the fineness of PSBE that reduces the volume of void space between cement and fine aggregate. It was effectively blocking the pore and enhances the durability. Consistently, the positive effect of incorporating of PSBE has decreased the rapid chloride ion permeability compared to that control foamed concrete. According to ASTM C1202-19 the foamed concrete containing 30% PSBE was considered low moderate permeability based on its charge coulombs value of less than 4000. Besides, the high chloride ion permeability in foamed concrete is because the current quickly passes through the specimen due to its larger air volume. In conclusion, incorporating PSBE in foamed concrete generates an excellent pozzolanic effect, producing more calcium silicate hydrate and denser foamed concrete, making it greater, fewer voids, and higher resistance to chloride penetration.