Dimensional Stability of Lightweight Foamed Concrete Containing Eggshell Powder and Calcium Stearate

In order to reduce eggshell (ES) waste and reduce utilization of pure cement, various researches were conducted to study effects of eggshell powder (ESP) on properties of concrete when it partially replaces ordinary Portland cement (OPC). Dimensional stability is one of the properties that related to cracking issue and soundness of concrete, and it is generally guided by movement of moisture. This study was conducted to study the sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete (LFC) that containing eggshell powder and calcium stearate (CS), where, replacement level (RL) of eggshell powder ranged from 0% to 10% at interval of 2.5%, and additional of 1% calcium stearate as cement mass applied for the mixture containing 0% and 5% eggshell powder. The result shows that eggshell powder improves sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete and the optimal replacement level is 5%. The result also shows that calcium stearate significantly improves these properties, regardless that incorporation of eggshell powder in the mixture containing calcium stearate might slightly deteriorate these properties. Besides, based on the results, improved sorptivity and initial surface absorption result in increased magnitude of shrinkage as the specimen has lower ability to absorb water for expansion throughout the testing period

Acoustic properties of lightweight foamed concrete with eggshell waste as partial cement replacement material

Nowadays, almost every industry needs to undergo green and sustainable industrial revolution due to pollutions like waste dumping and noise that deteriorating the environment. Therefore, feasibility study on application of eggshell waste as partial cement replacement in lightweight foamed concrete was conducted by aiming to solve environmental and acoustical issues, i.e. reduce eggshell waste and improve acoustic properties. In this study, compressive strength and acoustic properties of 1300 kg m-3 lightweight foamed concrete with and without 5% eggshell powder as partial cement replacement material were tested. Optimal water to cement ratio of 0.6 was obtained for acoustic properties test by comparing compressive strength result. The result shows that application eggshell powder has generally reduced 7 days compressive strength but improved 28 days compressive strength, and either improve or maintain acoustics properties, in which lightweight foamed concrete that containing eggshell powder has improved noise reduction coefficient at testing ages of 7, 28, and 90 days and improved sound transmission class at testing age of 56 and 90 days. Based on these results, 5% of eggshell powder is feasible to be incorporated into lightweight foamed concrete as partial cement replacement material for sound insulation and strength development purposes

Strength Properties of Foamed Concrete Containing Crushed Steel Slag as Partial Replacement of Sand with Specific Gradation

Lightweight construction material, notably foamed concrete, had become more favourable to reduce building weight and cost, accelerate construction process, and ease handling of precast segment. Simultaneously, rapid development had result in price rising of conventional material and environmental issue due to abundant wastes, for instance steel slag. As a consequence, feasibility of steel slag to be incorporated in lightweight foamed concrete for both structural and nonstructural purpose is worth to be investigated. This paper is aimed to evaluate the effects of crushed steel slag, as partial replacement of sand with specific gradation, on performance of lightweight foamed concrete (LFC) with density of 1600 kg/m3 to 1700 kg/m3 in terms of compressive and tensile strengths. Different steel slag based LFCs were developed by replacing 0, 25, 50, 75 and 100% of steel slag for sand. Different water to cement ratios (w/c) and dosages of super-plasticizer (sp) were adopted to confirm certain workability, strength properties was then studied for ages of 7 and 28 days. The laboratory results showed that lightweight foamed concrete with incorporation of crushed steel slag has decreased strength; however it still achieves structural strength of 17 MPa when replacement level is less than 25% at density of 1600 kg/m3 to 1700 kg/m3

Strength Properties of Foamed Concrete Containing Crushed Steel Slag as Partial Replacement of Sand with Specific Gradation

Lightweight construction material, notably foamed concrete, had become more favourable to reduce building weight and cost, accelerate construction process, and ease handling of precast segment. Simultaneously, rapid development had result in price rising of conventional material and environmental issue due to abundant wastes, for instance steel slag. As a consequence, feasibility of steel slag to be incorporated in lightweight foamed concrete for both structural and nonstructural purpose is worth to be investigated. This paper is aimed to evaluate the effects of crushed steel slag, as partial replacement of sand with specific gradation, on performance of lightweight foamed concrete (LFC) with density of 1600 kg/m3 to 1700 kg/m3 in terms of compressive and tensile strengths. Different steel slag based LFCs were developed by replacing 0, 25, 50, 75 and 100% of steel slag for sand. Different water to cement ratios (w/c) and dosages of super-plasticizer (sp) were adopted to confirm certain workability, strength properties was then studied for ages of 7 and 28 days. The laboratory results showed that lightweight foamed concrete with incorporation of crushed steel slag has decreased strength; however it still achieves structural strength of 17 MPa when replacement level is less than 25% at density of 1600 kg/m3 to 1700 kg/m3

Engineering Properties of 1200 kg/m³ Lightweight Foamed Concrete with Egg Shell Powder as Partial Replacement Material of Cement

This study presents the effects of egg shell powder on lightweight foamed concrete when partially replace the cement. At 2017, 12235 million eggs were consumed and around 85 thousand tonnes of egg shell waste was the yield in Malaysia. The waste might result in an environmental problem if it is not reused properly. Besides, large cement production also results in carbon dioxide emission and depletion of natural limestone. Therefore, studies on effects of egg shell powder on properties of lightweight foamed concrete as partial replacement of cement is attractive to be carried out by aiming to promote the application of lightweight foamed concrete as well as to mitigate the environmental issue by reducing the number of eggshell wastes and pure cement production. The objective of this study is to investigate the effects on engineering properties of lightweight foamed concrete with a fresh density of 1200 ± 50 kg/m3 when the cement is partially replaced by egg shell powder at replacement levels of 0%, 2.5%, 5%, 7.5%, and 10% by mass. The properties of the lightweight foamed concrete studied included workability, stability, compressive strength, flexural strength, water absorption, and sorptivity. The results show that the replacement of egg shell powder reduces the spread diameter, stability, and sorptivity, and improve the compressive and flexural strengths at replacement level of up to 5%. The eggshell powder is feasible to be used as partial cement replacement material for the production of the masonry unit

Dimensional Stability of Lightweight Foamed Concrete Containing Eggshell Powder and Calcium Stearate

In order to reduce eggshell (ES) waste and reduce utilization of pure cement, various researches were conducted to study effects of eggshell powder (ESP) on properties of concrete when it partially replaces ordinary Portland cement (OPC). Dimensional stability is one of the properties that related to cracking issue and soundness of concrete, and it is generally guided by movement of moisture. This study was conducted to study the sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete (LFC) that containing eggshell powder and calcium stearate (CS), where, replacement level (RL) of eggshell powder ranged from 0% to 10% at interval of 2.5%, and additional of 1% calcium stearate as cement mass applied for the mixture containing 0% and 5% eggshell powder. The result shows that eggshell powder improves sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete and the optimal replacement level is 5%. The result also shows that calcium stearate significantly improves these properties, regardless that incorporation of eggshell powder in the mixture containing calcium stearate might slightly deteriorate these properties. Besides, based on the results, improved sorptivity and initial surface absorption result in increased magnitude of shrinkage as the specimen has lower ability to absorb water for expansion throughout the testing period

Compressive Strength and Dimensional Stability of Palm Oil Empty Fruit Bunch Fibre Reinforced Foamed Concrete

Rapid drying shrinkage is an important factor in causing cracks of concrete. This research was aimed at studying the effects of Palm Oil Empty Fruited Bunch (POEFB) fibre on the drying shrinkage behaviour and compressive strength of foamed concrete (FC) under two different curing conditions. The adopted curing conditions were air curing and tropical natural weather curing. Two volume fractions of POEFB fibre were used, which were 0.25% and 0.50% based on dry mix weight with 1-2 cm in length. The dimensional stability of the control specimen and POEFB fibre reinforced FCs was obtained by cumulating the measured linear shrinkage or expansion due to different curing conditions. The results from the two different specimens were compared. The results showed that specimens reinforced with POEFB fibre and cured under tropical natural weather condition attained lesser variations of dimensional stability and higher 90-day strength performance index than the reference mix without POEFB fibre. This improvement was attributed to the ability of POEFB fibre to bridge the cement matrix, and irregular wetting process under tropical natural weather curing condition had enabled more production of Calcium Silicate Hydrate gels that gradually blocked the penetration of water into the specimens and increased the compressive strength. It is observed that 11.43% and 4.46% of improvement in 90-day strength performance index were obtained in natural weather cured 0.5% of POEFB fibre reinforced specimen, with corresponded to the reference mix and 0.25% of POEFB fibre reinforced specimens, respectively

Compressive Strength and Dimensional Stability of Palm Oil Empty Fruit Bunch Fibre Reinforced Foamed Concrete

Rapid drying shrinkage is an important factor in causing cracks of concrete. This research was aimed at studying the effects of Palm Oil Empty Fruited Bunch (POEFB) fibre on the drying shrinkage behaviour and compressive strength of foamed concrete (FC) under two different curing conditions. The adopted curing conditions were air curing and tropical natural weather curing. Two volume fractions of POEFB fibre were used, which were 0.25% and 0.50% based on dry mix weight with 1-2 cm in length. The dimensional stability of the control specimen and POEFB fibre reinforced FCs was obtained by cumulating the measured linear shrinkage or expansion due to different curing conditions. The results from the two different specimens were compared. The results showed that specimens reinforced with POEFB fibre and cured under tropical natural weather condition attained lesser variations of dimensional stability and higher 90-day strength performance index than the reference mix without POEFB fibre. This improvement was attributed to the ability of POEFB fibre to bridge the cement matrix, and irregular wetting process under tropical natural weather curing condition had enabled more production of Calcium Silicate Hydrate gels that gradually blocked the penetration of water into the specimens and increased the compressive strength. It is observed that 11.43% and 4.46% of improvement in 90-day strength performance index were obtained in natural weather cured 0.5% of POEFB fibre reinforced specimen, with corresponded to the reference mix and 0.25% of POEFB fibre reinforced specimens, respectively

Effects of tocotrienols supplementation on markers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Studies investigating the effects of tocotrienols on inflammation and oxidative stress have yielded inconsistent results. This systematic review and meta-analysis aimed to evaluate the effects of tocotrienols supplementation on inflammatory and oxidative stress biomarkers. We searched PubMed, Scopus, and Cochrane Central Register of Controlled Trials from inception until 13 July 2020 to identify randomized controlled trials supplementing tocotrienols and reporting circulating inflammatory or oxidative stress outcomes. Weighted mean difference (WMD) and corresponding 95% confidence interval (CI) were determined by pooling eligible studies. Nineteen studies were included for qualitative analysis, and 13 studies were included for the meta-analyses. A significant reduction in C-reactive protein levels (WMD: −0.52 mg/L, 95% CI: −0.73, −0.32, p < 0.001) following tocotrienols supplementation was observed, but this finding was attributed to a single study using δ-tocotrienols, not mixed tocotrienols. There were no effects on interleukin-6 (WMD: 0.03 pg/mL, 95% CI: −1.51, 1.58, p = 0.966), tumor necrosis factor-alpha (WMD: −0.28 pg/mL, 95% CI: −1.24, 0.68, p = 0.571), and malondialdehyde (WMD: −0.42 μmol/L, 95% CI: −1.05, 0.21, p = 0.189). A subgroup analysis suggested that tocotrienols at 400 mg/day might reduce malondialdehyde levels (WMD: −0.90 μmol/L, 95% CI: −1.20, −0.59, p < 0.001). Future well designed studies are warranted to confirm the effects of tocotrienols on inflammatory and oxidative stress biomarkers, particularly on different types and dosages of supplementation. PROSPERO registration number: CRD42020198241

Influence of Sputtering Temperature of TiO2 Deposited onto Reduced Graphene Oxide Nanosheet as Efficient Photoanodes in Dye-Sensitized Solar Cells

Renewable solar energy is the key target to reduce fossil fuel consumption, minimize global warming issues, and indirectly minimizes erratic weather patterns. Herein, the authors synthesized an ultrathin reduced graphene oxide (rGO) nanosheet with ~47 nm via an improved Hummer&rsquo;s method. The TiO2 was deposited by RF sputtering onto an rGO nanosheet with a variation of temperature to enhance the photogenerated electron or charge carrier mobility transport for the photoanode component. The morphology, topologies, element composition, crystallinity as well as dye-sensitized solar cells&rsquo; (DSSCs) performance were determined accordingly. Based on the results, FTIR spectra revealed presence of Ti-O-C bonds in every rGO-TiO2 nanocomposite samples at 800 cm&ndash;1. Besides, XRD revealed that a broad peak of anatase TiO2 was detected at ~25.4&deg; after incorporation with the rGO. Furthermore, it was discovered that sputtering temperature of 120 &deg;C created a desired power conversion energy (PCE) of 7.27% based on the J-V plot. Further increase of the sputtering temperature to 160 &deg;C and 200 &deg;C led to excessive TiO2 growth on the rGO nanosheet, thus resulting in undesirable charge recombination formed at the photoanode in the DSSC device