Ahmad Azrem Azmi
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Ahmad Azrem Azmi
Official Name
Ahmad Azrem, Azmi
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Azmi, Ahmad Azrem
Azrem, A. A.
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Scopus Author ID
55562182300
Researcher ID
AAA-1068-2021

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The properties of crumb rubber loading on fly ash based geopolymer mortar

2023 , Reshikesan Ravi , Ahmad Azrem Azmi , Mohd. Mustafa Al Bakri Abdullah , Lokman Hakim Ibrahim , Romisuhani Ahmad , Che Mohd Ruzaidi Ghazali

By replacing traditional Portland cement (OPC) with crumb rubber in fly ash-based geopolymer mortar, waste tyre disposal and natural mineral aggregate use can be reduced, resulting in lower CO2 emissions. Crumb rubber geopolymer mortar is formed when sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) are mixed with fly ash (class F) to make aluminosilicate gel. All of the fly ash geopolymer preparations followed the same ratio of solid to liquid (2:1) and the same ratio of NaOH solution (12M) to Na2SiO3 solution (2.5). Different amounts of crumb rubber (0%, 5%, 10%, 15%, and 20% by weight of solid) were added to the mixture. The results show that the compressive strength of the geopolymer mortar decreased with increasing crumb rubber loading. The results of the analysis show that the compressive strengths of CR-0%, CR-5%, CR-10%, CR-15%, and CR-20% are 25,59,14,31,11.19,10.38, and 8.16 MPa. The strength is diminished because of inadequate interfacial adhesion between the crumb rubber and geopolymer paste. As the sample weight fell, the percentage of crumb rubber in the geopolymer mortar in-creased, but the density decreased.

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Properties of crumb rubber loading on fly ash based geopolymer mortar for sandwich wall panel

2022 , Ahmad Azrem Azmi

The incorporation of crumb rubber into fly ash-based geopolymer mortar reduces the CO₂ emissions due to the exclusion of ordinary Portland cement (OPC), the number of waste tires entering the landfills and the amount of natural mineral aggregate being used in mortar. The fly ash (class F) reacts with an alkaline solution such as sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) to produce aluminosilicate gel that binds the crumb rubber to produce a crumb rubber geopolymer mortar (CRGM). NaOH solution (12M) and Na₂SiO₃ solution ratio were fixed constantly at 2.5, and the solid to liquid ratio was fixed at 2 for all fly ash geopolymer mixture. The additions of crumb rubber in the mixture by weight of solid were varied at 0%, 5%, 10%, 15% and 20%, respectively. The outer layer used for the crumb rubber geopolymer sandwich wall panel (CRGSWP) was primaflex with 9 mm thickness. The effect of different percentage crumb rubber loading on the compressive strength of fly ash-based geopolymer mortar was determined. Results show that the compressive strength of the CRGM decreased with the increase of crumb rubber loading. The compressive strength of CRGM-0, CRGM-5, CRGM-10, CRGM-15 and CRGM-20 at 28 days were 40.48 MPa, 36.13 MPa, 29.69 MPa, 23.13 MPa and 20.13 MPa, respectively. This reduction is due to poor interfacial adhesion between crumb rubber and cement components; thus, the strength is reduced. For the effect of elevated temperature exposure on the performance of CRGM, the mortars, at 28 days of curing time, were exposed to an elevated temperature at 200°C, 400°C, 600°C and 800°C. Results of the CRGM show a reduction in compressive strength and density while the percentage of weight loss increased with increasing crumb rubber loading at all elevated temperature exposure. The performance of CRGM and CRGSWP were tested and compared for their mechanical properties, sound absorption and thermal conductivity. CRGSWP and CRGM show a reduction in compressive and flexural strength as the crumb rubber loading increases. The sound absorption percentage of CRGSWP was higher compared to CRGM, which means that the sound absorption of CRGSWP is better than CRGM. CRGSWP-20 shows the highest percentage of sound absorption by 57.32% for the low frequency and 70.01% for the high frequency. Thermal conductivity test of the CRGSWP-20 (0.074 W/mK) shows better k-value than CRGM-20 (0.298 W/mK). This thesis expands the contribution of the findings of different percentage crumb rubber loading on the properties of CRGM at room temperature and elevated temperature exposure and the mechanical and thermal properties of CRGSWP as sandwich wall panel application.

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Crumb rubber geopolymer mortar at elevated temperature exposure

2022 , Ahmad Azrem Azmi , Mohd. Mustafa Al Bakri Abdullah , Che Mohd Ruzaidi Ghazali , Romisuhani Ahmad , Ramadhansyah Putra Jaya , Shayfull Zamree Abd. Rahim , Mohammad A. Almadani , Wysłocki, Jerzy J. , Agata Śliwa , Andre Victor Sandu

Low calcium fly ash is used as the main material in the mixture and the crumb rubber was used in replacing fine aggregates in geopolymer mortar. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) which were high alkaline solution were incorporated as the alkaline solution. The fly ash reacted with the alkaline solution forming alumino-silicate gel that binds the aggregate to produce a geopolymer mortar. The loading of crumb rubber in the fly ash based geopolymer mortar was set at 0%

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Crumb rubber geopolymer mortar at elevated temperature exposure

2022-01-01 , Ahmad Azrem Azmi , Mohd. Mustafa Al Bakri Abdullah , Che Mohd Ruzaidi Ghazali , Ahmad R. , Jaya R.P. , Shayfull Zamree Abd. Rahim , Almadani M.A. , Wysłocki J.J. , Śliwa A. , Sandu A.V.

Low calcium fly ash is used as the main material in the mixture and the crumb rubber was used in replacing fine aggregates in geopolymer mortar. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) which were high alkaline solution were incorporated as the alkaline solution. The fly ash reacted with the alkaline solution forming alumino-silicate gel that binds the aggregate to produce a geopolymer mortar. The loading of crumb rubber in the fly ash based geopolymer mortar was set at 0% (CRGM-0), 5% (CRGM-5), 10% (CRGM-10), 15% (CRGM-15), and 20% (CRGM-20), respectively. NaOH solution (12M) and Na2SiO3 solution ratio is set constant at 2.5 for all geopolymer mixture and the fly ash to alkali activator ratio was kept at 2.0. The CRGM at 28 days of curing time was exposed to elevated temperature at 200â—¦C, 400â—¦C, 600â—¦C and 800â—¦C. The weight loss of the CRGM increases with increasing temperature at all elevated temperatures. However, the density and compressive strength of CRGM decrease with an increase of crumb rubber loading for all elevated temperature exposure. The compressive strength of CRGM reduced due to the fact that rubber decomposes between 200â—¦C and 600â—¦C thereby creating voids. CRGM-15 and CRGM-20 showed cracks developed with rough surface at 800â—¦C. Image obtained from scanning electron microscope (SEM) showed that, the CRGM changed significantly due to the decomposition of crumb rubber and evaporation of the free water at 400â—¦C, 600â—¦C and 800â—¦C.

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A review on the effect of extrusion parameter on 3D printing filament diameter

2023 , Krishna Kumar Nitiyah , Luqman Musa , Mohamad Syahmie Mohamad Rasidi , Khairel Rafezi Ahmad , Shayfull Zamree Abd. Rahim , Rozyanty Rahman , Ahmad Azrem Azmi

Over the years, the extrusion technique has captured the attention of polymer industries by meeting the demand for polymer processing and fabrication of final products. Extrusion is a continuous process, and it has a lot of potential in the increasing polymer sector, especially in the three-dimensional (3D) printing sector. 3D printing is popular because the feedstock filament form is accessible and produce able. The properties of the filament used influence the printed part qualities regardless of the FDM parameters. This study provides information on how extrusion parameters affect the diameter of extruded filaments. This study reviews previous studies on the effect of varied extrusion settings on filament diameter. The review will serve as a resource for researchers in the 3D printing sector to fabricate their filaments for 3D printing. Overall, this paper will provide solutions to overcome issues in obtaining optimal filament diameters for future research projects.

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A review on graft compatibilizer for thermoplastic elastomer blend

2021-11-12 , Nitiyah K.K. , Luqman Musa , Mohamad Syahmie Mohamad Rasidi , Shayfull Zamree Abd. Rahim , Rozyanty Rahman , Ahmad Azrem Azmi , Rennie A.

A biodegradable thermoplastic elastomer (TPE) blend is developed by blending poly (lactic acid) (PLA) and natural rubber (NR) or epoxidized natural rubber (ENR) and it is a sustainable substitution in recent years for synthetic polymers. PLA is high in mechanical strength and compostable, but it is highly stiff and brittle. The incorporation of NR or ENR to PLA increases the impact strength and toughness of PLA. However, the disparity in polarity between PLA and elastomer phase like NR and ENR results in TPE blend being incompatible. Hence, compatibilization is essential to improve its polarity and develop interactions. Compatibilizer that composed of two different polymer is known is graft compatibilizer with the aid of grafting agent. The graft compatibilizers are divided into two categories. The first type is made up of one polymer and grafting agent and, the other one is composed of two polymer groups and grafting agent. These two types of graft compatibilizer can be prepared via two different method such as direct melt blending and solution. Apart from this, the TPE blend is produced via the melt blending technique with mixing machines such as internal mixer and extruder. This article has reviewed the preparation of the graft compatibilizer and blending technique of TPE. Based on the findings, the graft compatibilizers has a significant role in improving miscibility and compatibility across blend composed of different phase.

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A review on the potential of polylactic acid based thermoplastic elastomer as filament material for fused deposition modelling

2022-09-01 , Luqman Musa , Krishna Kumar N. , Shayfull Zamree Abd. Rahim , Mohamad Syahmie Mohamad Rasidi , Watson Rennie A.E. , Rozyanty Rahman , Yousefi Kanani A. , Ahmad Azrem Azmi

Currently, a range of sectors are implementing three-dimensional (3D) printing, which is a part of additive manufacturing (AM) technology via the fused deposition modelling (FDM) approach. As of now, various filament materials are available in the market and have their limitations. Thermoplastic elastomer (TPE) blend as a filament material in 3D printing should be implemented to overcome the weakness of available filaments. TPE blend stands out due to its flexibility, thermoplastic-like processability, and renewability. Based on the findings, TPE blend filament can be made with polylactic acid (PLA) thermoplastic and elastomers such as natural rubber (NR) and epoxidized natural rubber (ENR). The TPE printed components will be flexible; tough with excellent thermal and mechanical properties. In this paper, the characteristics of TPE are being reviewed to show the potential of TPE material as filament.

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Publication

Effect of crumb rubber on compressive strength of fly ash based geopolymer concrete

2016 , Ahmad Azrem Azmi , Mohd. Mustafa Al Bakri Abdullah , Che Mohd Ruzaidi Ghazali , Andrei Victor Sandu , Kamarudin Hussin

This study explores the effect of different percentage of crumb rubber on compressive strength of fly ash based geopolymer concrete. This research attempted to produce rubberized geopolymer concrete as an environmentally friendly, lightweight and durable product. Crumb rubber with ranged size from 73 μm to 375 μm was used in order to replace fine aggregates in geopolymer concrete. The replacements of crumb rubber were 0%, 5%, 10%, 15% and 20% in the fly ash based geopolymer concrete. The ratio of fly ash to alkaline activator was 2.5 and the ratio of Na2SiO3 to NaOH was fixed at 2.0. After the curing process, the strengths of the samples were tested on days 7 and 28. The results show that there is a reduction in all compressive strength for crumb rubber mixture, but still higher than normal rubberized concrete. Rubberized geopolymer concrete is a suitable solution in some non structural applications.

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The properties of styrene butadiene rubber/recycled chloroprene rubber (SBR/CRr) blends

2014 , Ahmad Azrem Azmi

The effects of cure characteristics, physical and mechanical properties and morphological properties on styrene butadiene rubber/recycled chloroprene rubber (SBR/CRr) blends were investigated. SBR/CRr blends with blend ratios 95/5, 85/15, 75/25, 65/35 and 50/50 were prepared using two roll mill at room temperature and followed by compression moulding. The results on comparison of styrene butadiene rubber/virgin chloroprene rubber (SBR/CRv) blends with SBR/CRr blends showed that at similar blend ratios, particularly up to 15 phr, SBR/CRr blends exhibited improvement in tensile strength while the M100, hardness and crosslink density of SBR/CRr blends exhibited increment value in all blend ratios. The smallest size of CRr particles S1 (346-486 μm) in SBR/CRr blends showed a better cure characteristics and mechanical properties compared with all other blend ratios in S2 (664-891 μm) and S3 (0.3-0.7 mm). Futhermore, the processing become more efficient and the contact surface area increased which provided more efficient interfacial bonds. The compatibilization of SBR/CRr blends with 5 phr of trans-polyoctylene rubber (TOR) improved the adhesion between CRr and the SBR matrix, thus, improving the compatibility of SBR/CRr blends. Cure characteristics of compatibilised SBR/CRr blend have shorter scorch time, t2 and cure time, t90 than uncompatibilised SBR/CRr blends. Compatibilised SBR/CRr blends showed lower minimum torque (ML) compared to uncompatibilised SBR/CRr blends at all blend ratios. However, maximum torque (MH) of compatibilised SBR/CRr blends exhibit the opposite trend compared with the uncompatibilised SBR/CRr blends. The tensile strength, M100, hardness and crosslink density of compatibilised SBR/CRr blends also improved compared with uncompatibilised SBR/CRr blends. The cure time, t90 of SBR/CRr/CB blends and SBR/CRr/CaCO3 blends decreased with increasing CRr content in both blends. However, scorch time, t2, increased with increasing CRr content in both blends. SBR/CRr/CB blends showed higher minimum torque (ML) compared to SBR/CRr/CaCO3 blends at all blend ratios. However, maximum torque (MH) of SBR/CRr/CB blends exhibit the opposite trend compared with the SBR/CRr/CaCO3 blends. SBR/CRr/CB blends exhibited a better result in all mechanical and physical properties compared with SBR/CRr/CaCO3 blends at all blend ratios.

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A review on the potential of polylactic acid based thermoplastic elastomer as filament material for fused deposition modelling

2022 , Luqman Musa , Nitiyah Krishna Kumar , Shayfull Zamree Abd. Rahim , Mohamad Syahmie Mohamad Rasidi , Allan Edward Watson Rennie , Rozyanty Rahman , Armin Yousefi Kanani , Ahmad Azrem Azmi

Currently, a range of sectors are implementing three-dimensional (3D) printing, which is a part of additive manufacturing (AM) technology via the fused deposition modelling (FDM) approach. As of now, various filament materials are available in the market and have their limitations. Thermoplastic elastomer (TPE) blend as a filament material in 3D printing should be implemented to overcome the weakness of available filaments. TPE blend stands out due to its flexibility, thermoplastic-like processability, and renewability. Based on the findings, TPE blend filament can be made with polylactic acid (PLA) thermoplastic and elastomers such as natural rubber (NR) and epoxidized natural rubber (ENR). The TPE printed components will be flexible; tough with excellent thermal and mechanical properties. In this paper, the characteristics of TPE are being reviewed to show the potential of TPE material as filament.

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