Optimal adherence to antiretroviral therapy (ART) remains the bedrock of effective therapy and management of human immunodeficiency virus (HIV). This systematic review examines the effect of interventions in improving ART adherence in sub-Saharan Africa (SSA), which bears the largest global burden of HIV infection. In accordance with PRISMA guidelines, and based on our inclusion and exclusion criteria, PUBMED, MEDLINE, and Google Scholar databases were searched for published studies on ART adherence interventions from 2010 to 2019. Thirty-one eligible studies published between 2010 to 2019 were identified, the categories of interventions were structural, behavioral, biological, cognitive, and combination. Study characteristics varied across design, intervention type, intervention setting, country, and outcome measurements. Many of the studies were behavioral interventions conducted in hospitals with more studies being randomized controlled trial (RCT) interventions. Despite the study variations, twenty-four studies recorded improvements. Notwithstanding, more quality studies such as RCTs should be conducted, especially among key affected populations (KAPs) to control transmission of resistant strains of the virus. Reliable objective measures of adherence should replace the conventional subjective self-report. Furthermore, long-term interventions with longer duration should be considered when evaluating the effectiveness of interventions.
MeSH terms: Behavior Therapy; Diagnostic Tests, Routine; Humans; Africa South of the Sahara/epidemiology; Medication Adherence*
Abdominal bloating (AB) is a prevalent and bothersome symptom, but there are no specific measures for severity and quality of life (QoL) other than the Bloating Severity Questionnaire (BSQ) and Bloating Quality of Life (BLQoL). We aimed to translate the BSQ and BLQoL into the Malay language and to validate them using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) approaches. The 12-item BSQ has two components, seven-item severity in general (SevGen) and five-item severity in the past 24 h (Sev24), and BLQOL has five items. Translation to the Malay language (BSQ-M and BLQoL-M) was performed using standard forward and backward processes. EFA followed by CFA were performed in participants with AB due to functional bowel disorders, with the purpose of examining the validity and reliability of the questionnaires translated into Malay. After EFA with 152 participants, all the items of BSQ-M remained in the model. Total variance extracted was 53.26% for BSQ-M and 58.79% for BLQoL-M. The internal consistency based on Cronbach's alpha values was 0.52 for SevGen, 0.86 for Sev24, and 0.81 for BLQoL-M. After performing CFA with another 323 participants, the final measurement model for BSQ-M and BLQoL-M fit the data well in terms of several fit indices (BSQ-M: root mean square error of approximation (RMSEA) = 0.050, Comparative Fit Index (CFI) = 0.966, Tucker-Lewis Fit Index (TLI) = 0.956, and standardized root mean squared residual (SRMR) = 0.051; BLQoL-M: RMSEA = 0.071, CFI = 0.985, TLI = 0.962, SRMR = 0.021). The composite reliability for BSQ-M and BLQoL-M were satisfactory (SevGen = 0.83, Sev24 = 0.89, BLQoL = 0.80). The intraclass correlation (ICC) results showed excellent stability for BSQ-M and BLQoL-M, ranging from 0.74 to 0.93. The Malay language versions of BSQ-M and BLQoL-M are valid and reliable instruments for measuring the severity and QoL of AB for the Asian population with functional bowel disorders.
MeSH terms: Humans; Language*; Malaysia; Psychometrics; Quality of Life*; Surveys and Questionnaires; Reproducibility of Results
Bacteria under the operational group Bacillus amyloliquefaciens (OGBa) are all Gram-positive, endospore-forming, and rod-shaped. Taxonomically, the OGBa belongs to the Bacillus subtilis species complex, family Bacillaceae, class Bacilli, and phylum Firmicutes. To date, the OGBa comprises four bacterial species: Bacillus amyloliquefaciens, Bacillus siamensis, Bacillus velezensis and Bacillus nakamurai. They are widely distributed in various niches including soil, plants, food, and water. A resurgence in genome mining has caused an increased focus on the biotechnological applications of bacterial species belonging to the OGBa. The members of OGBa are known as plant growth-promoting bacteria (PGPB) due to their abilities to fix nitrogen, solubilize phosphate, and produce siderophore and phytohormones, as well as antimicrobial compounds. Moreover, they are also reported to produce various enzymes including α-amylase, protease, lipase, cellulase, xylanase, pectinase, aminotransferase, barnase, peroxidase, and laccase. Antimicrobial compounds that able to inhibit the growth of pathogens including non-ribosomal peptides and polyketides are also produced by these bacteria. Within the OGBa, various B. velezensis strains are promising for use as probiotics for animals and fishes. Genome mining has revealed the potential applications of members of OGBa for removing organophosphorus (OPs) pesticides. Thus, this review focused on the applicability of members of OGBa as plant growth promoters, biocontrol agents, probiotics, bioremediation agents, as well as producers of commercial enzymes and antibiotics. Here, the bioformulations and commercial products available based on these bacteria are also highlighted. This review will better facilitate understandings of members of OGBa and their biotechnological applications.
For highly sensitive pH sensing, an electrolyte insulator semiconductor (EIS) device, based on ZnO nanorod-sensing membrane layers doped with magnesium, was proposed. ZnO nanorod samples prepared via a hydrothermal process with different Mg molar ratios (0-5%) were characterized to explore the impact of magnesium content on the structural and optical characteristics and sensing performance by X-ray diffraction analysis (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The results indicated that the ZnO nanorods doped with 3% Mg had a high hydrogen ion sensitivity (83.77 mV/pH), linearity (96.06%), hysteresis (3 mV), and drift (0.218 mV/h) due to the improved crystalline quality and the surface hydroxyl group role of ZnO. In addition, the detection characteristics varied with the doping concentration and were suitable for developing biomedical detection applications with different detection elements.
The fabrication of energy storage EDLC in this work is achieved with the implementation of a conducting chitosan-methylcellulose-NH4NO3-glycerol polymer electrolyte system. The simple solution cast method has been used to prepare the electrolyte. The impedance of the samples was fitted with equivalent circuits to design the circuit diagram. The parameters associated with ion transport are well studied at various plasticizer concentrations. The FTIR investigation has been done on the films to detect the interaction that occurs among plasticizer and polymer electrolyte. To get more insights into ion transport parameters, the FTIR was deconvoluted. The transport properties achieved from both impedance and FTIR are discussed in detail. It was discovered that the transport parameter findings are in good agreement with both impedance and FTIR studies. A sample with high transport properties was characterized for ion dominancy and stability through the TNM and LSV investigations. The dominancy of ions in the electrolyte verified as the tion of the electrolyte is established to be 0.933 whereas it is potentially stable up to 1.87 V. The rechargeability of the EDLC is steady up to 500 cycles. The internal resistance, energy density, and power density of the EDLC at the 1st cycle are 53 ohms, 6.97 Wh/kg, and 1941 W/kg, respectively.
MeSH terms: Electrolytes; Glycerol; Ions; Methylcellulose; Plasticizers; Polymers; Research; Electric Impedance; Ion Transport; Spectroscopy, Fourier Transform Infrared; Chitosan; Physical Phenomena
Ultraviolet (UV) photodetectors (PDs) based on high-quality well-aligned ZnO nanorods (NRs) were fabricated using both modified and conventional chemical bath deposition (CBD) methods. The modified chemical bath deposition (M-CBD) method was made by adding air bubbles to the growth solution during the CBD process. The viability and effectiveness of M-CBD were examined by developing UV PDs based on ZnO NRs. The ZnO nano-seed layer was coated on a glass substrate utilizing radiofrequency (RF) sputtering. The impact of the different growth-times on morphology, growth rate, crystal structure, and optical and chemical properties were investigated systematically using different characterization techniques, such as field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) analysis, UV-VIS double beam spectrometer, and energy dispersive X-ray analysis (EDX), respectively. The Al/ZnO UV PDs based on ZnO nanorods were fabricated with optimum growth conditions through the two methods of preparation. This study showed that the synthesized ZnO NRs using the M-CBD method for different growth times possess better properties than the conventional method under similar deposition conditions. Despite having the highest aspect ratio and growth rate of ZnO NRs, which were found at 4 h growth duration for both methods, the aspect ratio of ZnO NRs using the M-CBD technique was comparatively higher than the conventional CBD method. Besides, the UV PDs fabricated by the M-CBD method at 5 V bias voltage showed high sensitivity, short response time, quick recovery time, high gain, low dark current, and high photocurrent compared with the UV PD device fabricated by the conventional CBD method.
Geopolymer concrete has the potential to replace ordinary Portland cement which can reduce carbon dioxide emission to the environment. The addition of different amounts of steel fibers, as well as different types of end-shape fibers, could alter the performance of geopolymer concrete. The source of aluminosilicate (fly ash) used in the production of geopolymer concrete may lead to a different result. This study focuses on the comparison between Malaysian fly ash geopolymer concrete with the addition of hooked steel fibers and geopolymer concrete with the addition of straight-end steel fibers to the physical and mechanical properties. Malaysian fly ash was first characterized by X-ray fluorescence (XRF) to identify the chemical composition. The sample of steel fiber reinforced geopolymer concrete was produced by mixing fly ash, alkali activators, aggregates, and specific amounts of hook or straight steel fibers. The steel fibers addition for both types of fibers are 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume percentage. The samples were cured at room temperature. The physical properties (slump, density, and water absorption) of reinforced geopolymer concrete were studied. Meanwhile, a mechanical performance which is compressive, as well as the flexural strength was studied. The results show that the pattern in physical properties of geopolymer concrete for both types of fibers addition is almost similar where the slump is decreased with density and water absorption is increased with the increasing amount of fibers addition. However, the addition of hook steel fiber to the geopolymer concrete produced a lower slump than the addition of straight steel fibers. Meanwhile, the addition of hook steel fiber to the geopolymer concrete shows a higher density and water absorption compared to the sample with the addition of straight steel fibers. However, the difference is not significant. Besides, samples with the addition of hook steel fibers give better performance for compressive and flexural strength compared to the samples with the addition of straight steel fibers where the highest is at 1.0% of fibers addition.
The leaves of Carica papaya (CP) are rich in natural antioxidants. Carica papaya has traditionally been used to treat various ailments, including skin diseases. This study aims to decipher the antioxidant effects and phytochemical content of different CP leaf extracts (CPEs) obtained using supercritical carbon dioxide (scCO2) and conventional extraction methods. The antioxidant activities of CPEs were evaluated by cell-free (1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric-reduced antioxidative power (FRAP)) and cell-based (H2O2) assay. Both C. papaya leaf scCO2 extract with 5% ethanol (CPSCE) and C. papaya leaf scCO2 extract (CPSC) exhibited stronger DPPH radical scavenging activity than conventional extracts. In the FRAP assay, two hydrophilic extracts (C. papaya leaf ethanol extract (CPEE) and C. papaya freeze-dried leaf juice (CPFD)) showed relatively stronger reducing power compared to lipophilic extracts. Cell-based assays showed that CPFD significantly protected skin fibroblasts from H2O2-induced oxidative stress in both pre-and post-treatment. CPEE protected skin fibroblasts from oxidative stress in a dose-dependent manner while CPSCE significantly triggered the fibroblast recovery after treatment with H2O2. GC-MS analysis indicated that CPSCE had the highest α-tocopherol and squalene contents. By contrast, both CP hydrophilic extracts (CPEE and CPFD) had a higher total phenolic content (TPC) and rutin content than the lipophilic extracts. Overall, CPEs extracted using green and conventional extraction methods showed antioxidative potential in both cell-based and cell-free assays due to their lipophilic and hydrophilic antioxidants, respectively.
Laser-assisted high speed milling is a subtractive machining method that employs a laser to thermally soften a difficult-to-cut material's surface in order to enhance machinability at a high material removal rate with improved surface finish and tool life. However, this machining with high speed leads to high friction between workpiece and tool, and can result in high temperatures, impairing the surface quality. Use of conventional cutting fluid may not effectively control the heat generation. Besides, vegetable-based cutting fluids are invariably a major source of food insecurity of edible oils which is traditionally used as a staple food in many countries. Thus, the primary objective of this study is to experimentally investigate the effects of water-soluble sago starch-based cutting fluid on surface roughness and tool's flank wear using response surface methodology (RSM) while machining of 316 stainless steel. In order to observe the comparison, the experiments with same machining parameters are conducted with conventional cutting fluid. The prepared water-soluble sago starch based cutting fluid showed excellent cooling and lubricating performance. Therefore, in comparison to the machining using conventional cutting fluid, a decrease of 48.23% in surface roughness and 38.41% in flank wear were noted using presented approach. Furthermore, using the extreme learning machine (ELM), the obtained data is modeled to predict surface roughness and flank wear and showed good agreement between observations and predictions.
MeSH terms: Body Temperature Regulation; Family Characteristics; Hot Temperature; Lasers; Lubrication; Plant Oils; Stainless Steel; Starch; Temperature; Vegetables; Water; Friction; Lubricants
High requirements imposed by the competitive industrial environment determine the development directions of applied manufacturing methods. 3D printing technology, also known as additive manufacturing (AM), currently being one of the most dynamically developing production methods, is increasingly used in many different areas of industry. Nowadays, apart from the possibility of making prototypes of future products, AM is also used to produce fully functional machine parts, which is known as Rapid Manufacturing and also Rapid Tooling. Rapid Manufacturing refers to the ability of the software automation to rapidly accelerate the manufacturing process, while Rapid Tooling means that a tool is involved in order to accelerate the process. Abrasive processes are widely used in many industries, especially for machining hard and brittle materials such as advanced ceramics. This paper presents a review on advances and trends in contemporary abrasive machining related to the application of innovative 3D printed abrasive tools. Examples of abrasive tools made with the use of currently leading AM methods and their impact on the obtained machining results were indicated. The analyzed research works indicate the great potential and usefulness of the new constructions of the abrasive tools made by incremental technologies. Furthermore, the potential and limitations of currently used 3D printed abrasive tools, as well as the directions of their further development are indicated.
A wavy shape was used to enhance the thermal heat transfer in a shell-tube latent heat thermal energy storage (LHTES) unit. The thermal storage unit was filled with CuO-coconut oil nano-enhanced phase change material (NePCM). The enthalpy-porosity approach was employed to model the phase change heat transfer in the presence of natural convection effects in the molten NePCM. The finite element method was applied to integrate the governing equations for fluid motion and phase change heat transfer. The impact of wave amplitude and wave number of the heated tube, as well as the volume concertation of nanoparticles on the full-charging time of the LHTES unit, was addressed. The Taguchi optimization method was used to find an optimum design of the LHTES unit. The results showed that an increase in the volume fraction of nanoparticles reduces the charging time. Moreover, the waviness of the tube resists the natural convection flow circulation in the phase change domain and could increase the charging time.
The escalating trend of murder victim concealment worldwide appears worrying, and literature does not reveal any specific study focusing on victim concealment amongst convicted male Malaysian murderers. Therefore, this study was aimed at investigating the psychological traits that may underlie the act of murder concealment in Malaysia via mixed method approaches. Male murderers (n = 71) from 11 prisons were selected via purposive sampling technique. In the quantitative analysis, a cross-sectional study design using the validated questionnaire was used. The questionnaire contained murder concealment variables and four Malay validated psychometric instruments measuring: personality traits, self-control, aggression, and cognitive distortion. The independent sample t-tests revealed the significantly higher level of anger in murderers who did not commit concealment acts (8.55 ± 2.85, p < 0.05) when compared with those who did so (6.40 ± 2.64). Meanwhile, the Kruskal-Wallis H test revealed that anger and the personality trait of aggressiveness-hostility significantly varied across the different groups of murder concealment acts (p < 0.05). The qualitative data obtained via the in-depth interviews revealed two important themes for the murderers to commit murder concealment acts: (1) fear of discovery and punishment and (2) blaming others. These findings discussed from the perspectives of the murderers within the context of criminology and psychology may provide the first ever insight into the murder concealment acts in Malaysia that can benefit the relevant authorities for crime prevention and investigation efforts.
Colorectal cancer (CRC) is the third most commonly-diagnosed cancer in the world and ranked second for cancer-related mortality in humans. Microsatellite instability (MSI) is an indicator for Lynch syndrome (LS), an inherited cancer predisposition, and a prognostic marker which predicts the response to immunotherapy. A recent trend in immunotherapy has transformed cancer treatment to provide medical alternatives that have not existed before. It is believed that MSI-high (MSI-H) CRC patients would benefit from immunotherapy due to their increased immune infiltration and higher neo-antigenic loads. MSI testing such as immunohistochemistry (IHC) and PCR MSI assay has historically been a tissue-based procedure that involves the testing of adequate tissue with a high concentration of cancer cells, in addition to the requirement for paired normal tissues. The invasive nature and specific prerequisite of such tests might hinder its application when surgery is not an option or when the tissues are insufficient. The application of next-generation sequencing, which is highly sensitive, in combination with liquid biopsy, therefore, presents an interesting possibility worth exploring. This review aimed to discuss the current body of evidence supporting the potential of liquid biopsy as a tool for MSI testing in CRC.
Thermoplastic starch (TPS) hybrid bio-composite films containing microcrystalline cellulose (C) and nano-bentonite (B) as hybrid fillers were studied to replace the conventional non-degradable plastic in packaging applications. Raw oil palm empty fruit bunch (OPEFB) was subjected to chemical treatment and acid hydrolysis to obtain C filler. B filler was ultra-sonicated for better dispersion in the TPS films to improve the filler-matrix interactions. The morphology and structure of fillers were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). TPS hybrid bio-composite films were produced by the casting method with different ratios of B and C fillers. The best ratio of B/C was determined through the data of the tensile test. FTIR analysis proved the molecular interactions between the TPS and the hybrid fillers due to the presence of polar groups in their structure. XRD analysis confirmed the intercalation of the TPS chains between the B inter-platelets as a result of well-developed interactions between the TPS and hybrid fillers. SEM images suggested that more plastic deformation occurred in the fractured surface of the TPS hybrid bio-composite film due to the higher degree of stretching after being subjected to tensile loading. Overall, the results indicate that incorporating the hybrid B/C fillers could tremendously improve the mechanical properties of the films. The best ratio of B/C in the TPS was found to be 4:1, in which the tensile strength (8.52MPa), Young's modulus (42.0 MPa), elongation at break (116.4%) and tensile toughness of the film were increased by 92%, 146%, 156% and 338%, respectively. The significantly improved strength, modulus, flexibility and toughness of the film indicate the benefits of using the hybrid fillers, since these features are useful for the development of sustainable flexible packaging film.
Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study.
Living free from hunger is a basic human right. However, some communities still experience household food insecurity. This systematic literature review explored different aspects of household food insecurity in Malaysia including vulnerable groups, prevalence, risk factors, coping strategies, and the consequences of food insecurity. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Thirty-three relevant articles were selected from scientific databases such as CINAHL, Pubmed and Google Scholar, scrutiny of reference lists, and personal communication with experts in the field. The prevalence of household food insecurity in Malaysia was unexpectedly reported as high, with affected groups including Orang Asli, low-income household/welfare-recipient households, university students, and the elderly. Demographic risk factors and socioeconomic characteristics included larger household, living in poverty, and low education. Coping strategies were practices to increase the accessibility of food in their households. Consequences of household food insecurity included psychological, dietary (macro- and micronutrient intakes), nutritional status, and health impacts. In conclusion, this review confirmed that household food insecurity in Malaysia continues to exist. Nevertheless, extensive and active investigations are encouraged to obtain a more holistic and comprehensive picture pertaining to household food security in Malaysia.
People around the world ushered in the new year 2021 with a fear of COVID-19, as family members have lost their loved ones to the disease. Millions of people have been infected, and the livelihood of many has been jeopardized due to the pandemic. Pharmaceutical companies are racing against time to develop an effective vaccine to protect against COVID-19. Researchers have developed various types of candidate vaccines with the release of the genetic sequence of the SARS-CoV-2 virus in January. These include inactivated viral vaccines, protein subunit vaccines, mRNA vaccines, and recombinant viral vector vaccines. To date, several vaccines have been authorized for emergency use and they have been administered in countries across the globe. Meanwhile, there are also vaccine candidates in Phase III clinical trials awaiting results and approval from authorities. These candidates have shown positive results in the previous stages of the trials, whereby they could induce an immune response with minimal side effects in the participants. This review aims to discuss the different vaccine platforms and the clinical trials of the candidate vaccines.
Self-awareness of poorly arranged teeth can influence the quality of life. This study aimed to report the impacts of self-perceived malocclusion in young adults and the association between demographic characteristics and oral health related quality of life (OHRQoL). In this cross-sectional study, six-hundred-forty-three subjects from Selangor, Malaysia selected using a multistage sampling technique answered the Psychosocial Impact of Dental Aesthetics (PIDA) questionnaire and self-rated their dental appearance using the Aesthetic Component of the Index of Orthodontic Treatment Need. Data were analyzed using multifactorial ANOVA to identify the association between demographic characteristics and total PIDA score. Five-hundred-twenty-four subjects (81.5%) completed the questionnaires. Overall, 87.8% had impacts on their OHRQoL. Psychological impact was the most impacted domain (75.8%), followed by dental self-confidence (59.4%), social impact (48.9%) and aesthetic concern (22.1%). 16.8% reported significant impacts on all domains. Their mean PIDA score was 36.3 (SD 17.1). Prevalence, extent and severity of impacts were higher amongst those with self-perceived malocclusion. Gender, ethnicity, and self-perceived malocclusion status were associated with PIDA score (p < 0.05). Sub-urban and rural females had significantly higher PIDA scores than sub-urban and rural males. In conclusion, majority of Malaysian young adults especially those with self-perceived malocclusion were impacted by their dental aesthetics.
MeSH terms: Analysis of Variance; Cross-Sectional Studies; Esthetics; Esthetics, Dental; Ethnic Groups; Female; Humans; Malaysia; Male; Malocclusion; Quality of Life; Surveys and Questionnaires; Self Concept; Social Change; Prevalence; Young Adult; Index of Orthodontic Treatment Need
Immuno-oncology (IO) agents (anti-programmed cell death 1 (PD-1) and anti-programmed cell death-ligand 1 (PD-L1)) are approved as first- and second-line treatments for metastatic UC. PD-L1 expression levels in UC tumors help clinicians determine which patients are more likely to respond to IO therapies. Assays for approved IO agents use different antibodies, immunohistochemical protocols, cutoffs (defining "high" vs. "low" PD-L1 expression), and scoring algorithms. The robust control of pre-analytical and analytical standards is needed to obtain high-quality PD-L1 results. To better understand the status and perspectives of biomarker-guided patient selection for anti-PD-1 and anti-PD-L1 agents in UC, three workshops were held from December 2018 to December 2019 in Italy, Malaysia, and Spain. The primary goal was to develop recommendations for best practice approaches to PD-L1 testing in UC. Recommendations pertaining to the interpretation and reporting of the results of PD-L1 assays from experienced pathologists and oncologists from around the globe are included. A test request form for pathology laboratories was developed as a critical first step for oncologists/urologists to encourage communication between clinicians and pathologists, ensuring fast and high-quality test results. In this era of personalized medicine, we briefly discuss novel biomarkers being evaluated for IO agents in UC.
The alkali-silica reaction (ASR) is an important consideration in ensuring the long-term durability of concrete materials, especially for those containing reactive aggregates. Although fly ash (FA) has proven to be useful in preventing ASR expansion, the filler effect and the effect of FA fineness on ASR expansion are not well defined in the present literature. Hence, this study aimed to examine the effects of the filler and fineness of FA on ASR mortar expansion. FAs with two different finenesses were used to substitute ordinary Portland cement (OPC) at 20% by weight of binder. River sand (RS) with the same fineness as the FA was also used to replace OPC at the same rate as FA. The replacement of OPC with RS (an inert material) was carried out to observe the filler effect of FA on ASR. The results showed that FA and RS provided lower ASR expansions compared with the control mortar. Fine and coarse fly ashes in this study had almost the same effectiveness in mitigating the ASR expansion of the mortars. For the filler effect, smaller particles of RS had more influence on the ASR reduction than RS with coarser particles. A significant mitigation of the ASR expansion was obtained by decreasing the OPC content in the mortar mixture through its partial substitution with FA and RS.
MeSH terms: Alkalies; Body Weights and Measures; Construction Materials; Excipients; Manufactured Materials; Silicon Dioxide; Rivers; Coal Ash