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Structures exposed to high temperatures must have enhanced thermal stability and mechanical properties. It is essential to utilise sustainable materials in the endeavour to achieve this objective. This study investigates the combined effects of natural rubber latex (NRL) and hybrid fibres in high-volume fly ash (HVFA) concrete. It introduces a novel approach of utilising NRL as a partial cement replacement at varying percentages of 2.5%, 5%, 7.5%, and 10%. Replacing cement with 2.5% NRL resulted in optimal performance. Higher percentages of NRL enhanced the concrete’s workability, with 10% NRL producing a maximum slump of 54 mm. Adding 2.5% and 5% NRL significantly reduced water absorption by 12–18% compared to the control sample. Compressive strength decreased with higher NRL contents. The smallest reduction of 8% occurred with 2.5% replacement, and the highest loss of 55% was at 10% replacement. In contrast, tensile and flexural strengths improved by 14% and 31%, respectively, after 28 days of curing. The concrete with 2.5% NRL retained more strength at elevated temperatures, with a loss of strength of 20% at 600 °C compared to 25% for the control. The microstructural analysis revealed that the optimal NRL percentage resulted in a denser matrix, supporting the mechanical results. Generally, incorporating 2.5% NRL with hybrid fibres in HVFA concrete enhances durability and thermal resistance while maintaining satisfactory strength, offering a sustainable approach for high-performance applications.

Natural rubber is of significant economic importance owing to its excellent resilience, elasticity, abrasion and impact resistance. Despite that, natural rubber has been identified with some drawbacks such as low modulus and strength and therefore opens up the opportunity for adding a reinforcing agent. Apart from the conventional fillers such as silica, carbon black and lignocellulosic fibers, nanocellulose is also one of the ideal candidates. Nanocellulose is a promising filler with many excellent properties such as renewability, biocompatibility, non-toxicity, reactive surface, low density, high specific surface area, high tensile and elastic modulus. However, it has some limitations in hydrophobicity, solubility and compatibility and therefore it is very difficult to achieve good dispersion and interfacial properties with the natural rubber matrix. Surface modification is often carried out to enhance the interfacial compatibilities between nanocellulose and natural rubber and to alleviate difficulties in dispersing them in polar solvents or polymers. This paper aims to highlight the different surface modification methods employed by several researchers in modifying nanocellulose and its reinforcement effects in the natural rubber matrix. The mechanism of the different surface medication methods has been discussed. The review also lists out the conventional filler that had been used as reinforcing agent for natural rubber. The challenges and future prospective has also been concluded in the last part of this review.

The block shear bonding performance was studied for glued laminated timber (glulam) manufactured from laran, a Malaysian plantation hardwood, under four treatment conditions designed to simulate service environments. Forty block shear specimens were tested to determine shear strength and wood failure percentage (WFP). The conditions comprised (a) dry (control, equilibrium laboratory climate), (b) water-soak (immersion in 20 ± 3 °C water for 24 h), (c) boiling Immersion (100 °C for 6 h followed by cooling), and (d) boil–dry–boil cycle (repeated hot–wet and drying exposure). Each specimen (50 × 50 × 50 mm³) was loaded in shear using a universal testing machine. Results revealed a progressive reduction in both shear strength and WFP with increasing treatment severity. Dry samples exhibited the highest bonding performance, while specimens subjected to the Boil–Dry–Boil Cycle showed the greatest deterioration. These findings demonstrate the sensitivity of laran glulam to moisture and thermal cycling, provide baseline data for adhesive bond durability across service classes, and offer valuable insights for improving treatment strategies, product design, and the long-term structural reliability of glulam in tropical construction contexts.

Timber connections were prepared using glulam from tropical plantation species, focusing on key properties for dowel-type joints with half threaded bolts without nuts: Bolt bearing strength and bolt withdrawal capacity. Tests were performed according to ASTM standards. Three half-threaded bolt diameters (12 mm, 16 mm, and 20 mm) were tested in two loading directions, parallel and perpendicular to the grain, with 12 replicates for each configuration. Response Surface Methodology (RSM) using Design Expert Software was applied to optimize bolt diameter for both loading directions. Results showed that bolt bearing strength was higher in perpendicular loading, with the 12 mm bolt achieving 16.6 N/mm², compared to 6.01 N/mm² in parallel loading. Withdrawal capacities varied, with the 16 mm bolt showing the highest capacity in perpendicular loading at 54.2 kN. The study demonstrates that the 16 mm bolt exhibited the optimal diameter-to-embedment length ratio compared to 12 mm and 20 mm bolts, resulting in the highest withdrawal capacity. Consequently, the 16 mm bolt represented the best balance for achieving maximum withdrawal capacity. The optimization suggests using a 16 mm bolt for parallel loading to the grain and a 14 mm bolt for perpendicular loading.

The design practice has shifted from permissible stress design to limit state design using Eurocode 5 (EC5), which introduces design strength optimization. However, the adoption of EC5 in Malaysia cannot be done directly due to the absence of design strength data for Malaysian timber species. This paper presents a study that evaluates the bending strength properties, moisture content, and density of kekatong (Cynometra malaccensis) timber specimens using the Weibull theory to produce 1/k values for the local timber species. The depth impact adjustment factors for kekatong timber had a value of 0.23, which is not far from the well-established 1/k value of 0.2 for softwood and temperate hardwood with characteristic densities below 700 kg/m3 in EC5. The study shows that the bending strength of local timber is affected by its volume, and the variation of bending strength at several probabilities is in close agreement with theoretical predictions. Overall, the study provides important insights for the design of timber structures using Malaysian timber species, which can be used to improve the safety and sustainability of timber structures.

The design practice of timber structures in Malaysia is still based on permissible stress codes as stated in Malaysian Standard (MS) 544: Part 2 and MS 544: Part 3, which was adopted from the British Standard (BS) 5268. The British Standard was later completely replaced by Eurocode 5 (EC5) in 2009. Therefore, to preserve the continuity of design concepts specified in the British code of practice, local designers should adopt an EC5 limit state design to generate safe and economical designs. However, new strength data based on characteristic values which comply with EC5 for Malaysian tropical hardwoods are still lacking. The aim of this study was to investigate the compressive strength properties of nine structural-sized Malaysian tropical hardwood species namely Balau, Kempas, Kelat, Resak, Kapur, Keruing, Mengkulang, Light Red Meranti and Geronggang tested according to European Standard (EN) 408. A compression test was performed to measure the compressive strength and modulus of elasticity of the timbers and were used to derive characteristic values. The equation for determining characteristic compressive strength given in EN 384 was also assessed to verify that whether it is suitable for high density Malaysian hardwoods, as this equation was derived from softwood and European hardwoods. The results revealed that the derived characteristic values are higher than the values given in EN 338 for the relevant strength classes, particularly for heavy and medium hardwood with densities greater than 700 kg/m3. A verification of the equation used in EN 384 to determine compressive strength characteristic value yields a different equation, fc,0,k=2.2 fm,k0.7. This shows that the EN 384 equation is not suitable to be used with hardwood timber with a density more than 700 kg/m3, since it will underestimate the strength value.

The depth adjustment factor for bending strength stated in Eurocode 5 (EC5) is only applicable to timbers having a characteristic density below 700 kg/m3. However, most Malaysian timbers are hardwood, some with a characteristic density reaching above 700 kg/m3. Therefore, the objective of this study was to examine whether the depth adjustment factor stipulated in EC5 is valid for Malaysian hardwood timbers. Six timber species were selected for this study, namely Kapur (Dryobalanops C.F.Gaertn.), Kempas (Koompassia Maingay ex Benth.), Keruing (Dipterocarpus C.F.Gaertn.), Light red meranti (Shorea Roxb. ex C.F.Gaertn.), Geronggang (Cratoxylum Blume) and Balau (Shorea Roxb. ex C.F.Gaertn.). The determination of bending strength and characteristic density was conducted according to BS EN 408: 2010 and BS EN 384: 2016, respectively. A graph for mean bending strength vs. (150/h) was plotted for each timber species. The power function was selected to analyze the relationship between the two variables. The power of the regression equations varied depending on the characteristic density of the timber species. For species with a characteristic density below 700 kg/m3, such as Kapur, Keruing, and Light red meranti, the power was between 0.16 to 0.17. In contrast, for species having a characteristic density above 700 kg/m3, namely Kempas and Balau, the power was higher at 0.23 and 0.24, respectively. Geronggang was an exception to this pattern. These values are close to the depth adjustment factor given in EC5, which is 0.2. Based on the results, it can be suggested that the adjustment factor of 0.2 is also applicable to Malaysian hardwood timbers with a characteristic density above 700 kg/m3

This study investigated the bending, compression as well as the bonding performance of CLT panels made from fast-growing timber species, i.e., Laran (Neolamarckia cadamba) and Batai (Paraserianthes falcataria). The variables studied were timber species (Laran and Batai), layers of lamination (3-layer and 5-layer), loading direction in bending (in-plane and out-of-plane), loading direction in compression (x-, y-, and z-axis) and different treatment conditions for bonding performance test. The desired outputs of this study were bending and compression properties (strength and stiffness) as well as bonding performance (block shear strength, wood failure percentage and delamination value). The bending and compression test were conducted according to EN16351:2015 and EN408:2012, respectively. On the other hand, the bonding performance test was determined by block shear and delamination test based on EN16351:2015 and EN14374:2004, respectively. Prior to block shear test, the samples were subjected to three different treatment conditions. The results showed that CLT made from 3-layer Laran timber, loaded at out-of-plane direction exhibited the highest bending properties. Contrarily, CLT made from 5- layered Batai timber, loaded at in-plane direction showed the lowest bending properties. Laran samples for compression loaded at x-axis exhibited the best compressive properties. Generally, Laran CLT showed greater bonding performance determined by shear test compared to Batai CLT for both 3- and 5-layer panels. On the contrary, delamination results showed that Batai CLT demonstrated better bonding performance compared to Laran CLT. In terms of bonding performance measured by wood failure percentage (WFP), most samples under various treatment conditions showed WFP ≥ 80% except for samples under wet condition with WFP ≤ 60%.

Purpose>The quality of asthma care may be affected if asthma management is overlooked, thus needing frequent clinical audits to identify areas for improvement. The purpose of this paper is to evaluate the quality of the process (e.g. documentation of asthma-specific information), the structure (e.g. availability of resources) and the outcome (e.g. proportion of patients prescribed with asthma medications) at a university-based primary care clinic. The associated clinical factors for non-documentation of asthma control at the last visit were also examined.Design/methodology/approach>This retrospective study involved auditing medical records and the pharmacy data system of 433 adult patients with asthma to evaluate 18 quality indicators. The standard target for the indicators of process and structure was 80 percent and the standard target for the indicators of outcome was 100 percent.Findings>All the indicators failed to reach the standard targets. Documentation of asthma-specific information and availability of resources were deficient. The non-documentation of asthma control was significantly associated with presence of acute complaint(s) unrelated to asthma, presence of other issues and number of the documented parameters for asthma control. Although the prescription rates of inhaled reliever and preventer were substandard, they were reasonably high compared to the targets.Research limitations/implications>In this study, evaluation of the quality of care was limited by absence of asthma register, use of paper-based medical records and restricted practice capacity. Besides, the asthma-specific assessments and management were only audited at one particular time. Furthermore, the findings of this study could not be generalised to other settings that used other methods of record keeping such as patient-held cards and electronic medical records. Future studies should sample asthma patients from a register, evaluate more reliable quality indicators (e.g. over-prescription of short-acting β-2 agonist and underuse of inhaled corticosteroid) and assess asthma management over a duration of time.Practical implications>This study provides quality information on all aspects of asthma care (process, structure and outcome) which can be a basis for clinical improvement. It is hoped that the study could assist the stakeholders to plan strategies for improvement of the asthma care. A more strategic and reliable system of documentation is needed, such as the use of a simple template or structured form, which should not jeopardise the provision of personalised and comprehensive care. With complete documentation, thorough investigational audits can be continuously performed to determine the quality of asthma care.Social implications>This study could provide useful findings to guide healthcare providers in developing a more strategic model of asthma care that can ensure asthma patients to receive a personalised, comprehensive, holistic and continuous care. Through this approach, their physical and psychosocial well-being can be optimised.Originality/value>Even though our healthcare has advanced, the quality of asthma care is still suboptimal which requires further improvement. However, it could be considered assuring due to high outcome levels of asthma care despite having limited resources and practice capacity.

Polymer admixtures have proven to increase the compressive strength as well as durability properties of concrete, however when natural rubber latex (NRL) is used as the polymer admixture for sustainable construction materials, the strength reduced, yet the high temperature performance is of interest. This study includes 2.5% NRL (2.5NRLHPC) in hybrid steel (1%) and polypropylene (0.1%PP) fibre high performance concrete (HPC) with high volume fly ash (52.5%) and nano silica (2.5%) as admixture while the control sample consist of 0% NRL (CHPC). The specimens were evaluated for residual compressive strength, mass loss, colour changes, crack formation and microstructural characteristics after exposure to 300°C and 600°C. Results shows that the compressive strength of 2.5NRLHPC (52 MPa) decrease to 50 MPa and for CHPC (56 MPa) increase to 60 MPa at 300°C as expected based on previous studies. However at 600°C, the strength of 2.5NRLHPC reduces less than the CHPC (at 20% compares to 25%) to 41 MPa and 42 MPa, respectively. This shows that adding 2.5% NRL to HPC produces high temperature resistance concrete comparable to the control in term of strength. The mass loss, colour changes, crack formation, FESEM images explain the results of the comparable performance with slight weaknesses of the NRL concrete.