Thai Cultivated Banana Fibers as The Sustainable Sound and Heat Insulation Materials

This study was aimed to develop on the sound absorber and the heat insulator derived from natural fiber (cultivated banana fiber) to be an alternative way. Normally, the community consume this equipment derived from synthetic materials (asbestos and fiberglass) which cause of the negative human health. The process of specimen preparation was started by the banana stem cutting-off step to prepare banana fibers which had been determined to slit of 2-3 mm fiber diameter by cutter and then dehydrated on these banana fibers. Eventually, a high-speed of grinder was applied to mill these fibers and then the 30 US MESH size of filter was utilized to 0.6 mm reducing fiber length. Therefrom, this cultivated banana fiber was prepared to test on Noise Reduction Coefficient (NRC) and Thermal Conductivity (TC) according to various factors: (1) banana fiber-gypsum ratio on 2:8 and 3:7 by weight, (2) banana fiber length of 0.6 mm and (3) 25.0 mm thickness of each specimen. These experiments were determined on the NRC value based on ISO10534-2 standard at frequency range 250-4,000 Hertz and the TC value based on ASTM C518 standard. In addition, the structural and scattering images of banana fiber and surface were investigated by Scanning Electron Microscope (SEM). The NRC result showed as 0.52 of banana fiber specimen in the length of 0.6 mm and banana fiber-gypsum ratio on 3:7 by weight that appeared more porosity and space area. Likewise, the TC result was found at 0.063 W/m.K. Consequently, this local natural material prepared by cultivated banana fiber was proven effective in noise reducing and heat-insulating purposes for Thailand’s community.Keywords: Cultivated Banana Fiber; Noise Reduction Coefficient; Thermal Conductivit

Influence of calcium carbonate on green self-compacting concrete incorporating porcelain tile waste as coarse aggregate replacement

The disposal of ceramic tile waste poses a significant environmental challenge in the construction industry. This study aims to explore the influence of calcium carbonate (CC) on the properties of self-compacting concrete (SCC) incorporating porcelain tile waste as a coarse aggregate replacement. The objective is to enhance the performance of SCC while addressing the limitations of recycled ceramic aggregates and achieving the desired strength class. SCC specimens were cast by partially and completely substituting natural crushed rock with varying percentages of porcelain tile aggregates (PTA-0, 25 %, 50 %, 75 %, and 100 %) and cement with calcium carbonate (CC-10 %, 20 %, and 30 %). Workability assessments, mechanical properties, and durability were evaluated and compared against those of reference concrete. The experimental findings revealed that the incorporation of CC and PTA positively influenced the workability, mechanical properties and durability of SCC. Notably, the SCC mixture incorporating 10 %CC and 25 %PTA demonstrated exceptional performance, achieving the highest compressive strength of 64.9 MPa at 28 days. Moreover, even with complete substitution, the compressive strength reduction remained below 5 %. These results highlight the potential of PTA and CC-based SCC mixtures as an efficient and sustainable approach for utilizing porcelain tile waste in high performance concrete production. The findings contribute to addressing environmental concerns, promoting waste management practices, and reducing the reliance on natural resources in the construction industry

Characteristics of non-steady-state chloride migration of self-compacting concrete containing recycled concrete aggregate made of fly ash and silica fume

Chloride migration poses a significant challenge to the long-term durability of concrete structures due to its potential to corrode reinforcement and deteriorate the structure. This study focuses on chloride migration in self-compacting concrete (SCC) made with pozzolans, namely silica fume (SF) and fly ash (FA), along with recycled concrete aggregate (RCA). Particularly, the effects of external electrical potential (power-on) duration and RCA content on the features of SCC were examined, alongside the influence of pozzolanic materials, focusing on the chloride migration coefficient and mechanical properties. Six groups of SCC mixtures were created with varying proportions of SF and FA, and different levels of RCA replaced the natural coarse aggregate. The findings reveal a multifaceted impact on SCC behaviour. The chloride migration coefficient exhibits a distinct pattern as the power-on duration increases from 12 to 36 h. Initially, the coefficient increases and then decreases, demonstrating a healing and sealing mechanism within the concrete matrix, which enhances resistance to chloride penetration. The chloride migration coefficient significantly decreased with adding SF and FA. With 15% SF and 30% FA, the coefficient decreased to 59.9% and 49.5%, respectively. Moreover, incorporating RCA in SCC mixtures significantly influences coefficient levels. RCA inclusion at 20% remarkably decreased the coefficient after 12 h by 16.17%. Subsequently, the levels decreased by 39.49% and 46.87% after 24 and 36 h, respectively, compared to the control mixture. This behaviour highlights the importance of RCA in enhancing the resistance of SCC to chloride ingress, a crucial factor for long-term durability. Additionally, mechanical properties such as splitting tensile strength, ultrasonic pulse velocity and surface hardness consistently improved with longer power-on durations and higher RCA and SF content. SCC with RCA and pozzolanic materials exhibits enhanced chloride resistance and superior mechanical performance, making it ideal for sustainable concrete production

Self-compacting concrete produced with recycled concrete aggregate coated by a polymer-based agent: A case study

Understanding the effects of recycled concrete aggregate (RCA) and polymer impregnation on the properties of self-compacting concrete (SCC) is crucial for the construction industry's efforts to reduce environmental impact and utilise recycled materials. This study aims to examine the impact of RCA inclusion and polymer impregnation on the properties of SCC, in response to the urgent demand for sustainable construction practices. Two different methods of polymer impregnation were evaluated to assess their impact on the workability and hardened characteristics of SCC. The SCC mixtures were prepared using river sand (natural fine aggregate (NFA)), natural crushed limestone (natural coarse aggregate (NCA)) and a polymer impregnation level of 0.05 wt% of the water content, with a water-to-cement ratio of 0.34. RCA was used as a complete replacement for NFA and NCA, adhering to the American Society for Testing and Materials (ASTM) C33 standards for recycled fine concrete aggregate (RFCA) and recycled coarse concrete aggregate (RCCA)The workability of the SCC mixtures was evaluated based on the criteria set by the European Federation of National Associations Representing for Concrete (EFNARC). Among the hardened properties, the compressive strength of the hardened properties was tested at four different time intervals (1, 3, 7 and 28 days), and the integrity of the SCC specimens was assessed using ultrasonic pulse velocity. The polymer impregnation process resulted in a slower compressive strength development rate compared to that observed in the control concrete. However, combining polymer impregnation type 1 with either RFCA and NCA or RCCA and NFA significantly increased the 28-day compressive strength by 5.02% and 1.80%, respectively. These findings provide valuable insights into the behaviour of SCC incorporating RCA and polymer impregnation. Optimising the selection and combination of materials can enhance the performance and sustainability of SCC in construction applications

Recycling prestressed concrete pile waste to produce green self-compacting concrete

Construction and demolition waste is produced in large quantities and constitutes an overlooked resource with significant potential for recycling and reuse. In fact, recycled concrete aggregate (RCA) has a high resource value, although it is also the case that RCA has characteristics that complicate its reuse. This research study looks at the efficacy of producing green self-compacting concrete (SCC) using uniform in-situ prestressed concrete pile waste (RCA) as a replacement for natural aggregate and fly ash (FA) as a replacement for Type 1 Portland cement (OPC). In accordance with the European standard, the workability characteristics of the SCC mixtures were assessed using slump flow, T500 time, J-ring flow, L-box, and V-funnel tests. The hardened properties of compressive strength at 7, 28, and 91 days as well as pulse velocity, Young's modulus, and surface resistivity were also tested. Based on this study, it is possible to produce SCC with both RCA and FA that has better workability and hardened properties than does RCA and also to reduce the negative effects of the latter. SCC produced without coarse natural aggregates showed compressive strength above 50 MPa and maximum compressive strength above 74 MPa at 91 days. SCC produced in this way is, therefore, viable for industrial use

สมบัติทางวิศวกรรมของบล็อคปูพื้นคอนกรีตพรุนจากผิวทางแอสฟัลต์เก่านำมาใช้ใหม่โดยการแทนที่มวลรวมหยาบ

วารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 1 (ม.ค.-มิ.ย 2565), หน้า 41-52This research aimed to study the use of coarse aggregate obtained from removing old recycled asphalt pavement (RAP) in the production of the porous concrete paving block. Crushing and size separation of the coarse aggregate by using standard sieve size by selected the gradation size of the coarse aggregate that passed to sieve size 1/2” and retained on sieve size 3/8” and other that passed to sieve size 3/8” and retained on sieve size No.4 by mixing ratio 50 : 50 of the mass as replaced natural coarse aggregate. Portland cement quantity about 18% and 20% by weight of the aggregate. The water to cement ratio was 0.30 and 0.35 respectively. Compressive strength, flexural strength, and water permeability were investigated. The results showed that the cement content and water to cement ratio was influenced the strength properties and water permeability rate of the porous concrete paving block. The porous concrete paving block mixed with higher cement content (20%) had the compressive strength at the age of 28 days increased by 16-24% when compared with lower cement content (18%). On the other hand, the water permeability rate decreased by 5.1-8.1%.Rajamangala University of Technology Phra Nakho

สมบัติทางวิศวกรรมของมอร์ตาร์ผสมเส้นใยแปรใช้ใหม่จากขยะแผงวงจรพิมพ์ Engineering Properties of Mortars Incorporating Recycled Fibers from Waste Printed Circuit Boards

งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษาสมบัติทางวิศวกรรมของมอร์ตาร์ผสมเส้นใยแปรใช้ใหม่จากขยะแผงวงจรพิมพ์โดยนำมาใช้เป็นสารผสมเพิ่ม (Admixture) ในอัตราส่วนที่ต่างกัน ทำศึกษาองค์ประกอบทางเคมี และสมบัติทางกายภาพ ได้แก่ ขนาดคละ และลักษณะอนุภาคและพื้นผิวด้วยกล้องจุลทรรศน์อิเล็กตรอนแบบส่องกราด สมบัติของมอร์ตาร์ในสภาวะเหลวและแข็งตัว ได้แก่ การไหลแผ่ เวลาก่อตัว กำลังอัด กำลังดัด สมบัติทางความร้อนและการวิเคราะห์ปริมาณโลหะหนักที่ปะปนอยู่ในมอร์ตาร์ ผลการศึกษาพบว่า เส้นใยแปรใช้ใหม่ จากแผงวงจรอิเล็กทรอนิกส์ส่วนใหญ่มีลักษณะเป็นแท่งทรงกระบอกขนาดเส้นผ่าศูนย์กลางประมาณ 12-15 mm มีความยาวตั้งแต่ 30 - 200 mm มอร์ตาร์มีแนวโน้มการไหลแผ่และเวลาการก่อตัวเพิ่มขึ้นเมื่อปริมาณเส้นใยแปร ใช้ใหม่จากแผงวงจรอิเล็กทรอนิกส์เพิ่มขึ้น ในขณะที่กำลังอัด กำลังดัดและสัมประสิทธิ์การนำความร้อนมีแนวโน้มลดลง เมื่อพิจารณามอร์ตาร์ผสมเส้นใยแปรใช้ใหม่จากแผงวงจรอิเล็กทรอนิกส์ร้อยละ 20 พบว่า มีกำลังอัดและกำลังดัดสูงสุด เท่ากับ 36.35 MPa และ 15.66 MPa ที่อายุ 28 วัน ตามลำดับ นอกจากนี้ปริมาณโลหะหนักที่ปะปนอยู่ในมอร์ตาร์ผสมเส้นใยแปรใช้ใหม่จากแผงวงจรอิเล็กทรอนิกส์ มีค่าอยู่ในเกณฑ์มาตรฐานที่กำหนดตามประกาศของคณะกรรมการสิ่งแวดล้อมแห่งชาติThe purpose of this research was to investigate the engineering properties of mortar incorporating recycled fibers from waste-printed circuit boards used as admixtures at varying ratios. The study examined the chemical composition and physical characteristics of the fibers, including particle size gradation, shape, and surface properties, using scanning electron microscopy. Additionally, the study evaluated the fresh and hardened properties of the mortar, such as initial flow, setting time, compressive strength, flexural strength, thermal properties, and heavy metal concentration. The results showed that the majority of recycled fibers from waste electronic circuit boards were cylindrical rods with a diameter of approximately 12-15 mm and lengths ranging from 30 to 200 mm. As the number of recycled fibers from waste printed circuit boards increased in the mortar, the initial flow and setting time increased, while the compressive strength, flexural strength, and thermal conductivity coefficient decreased. Mortars containing 20% recycled fibers from waste electronic circuit boards exhibited the highest compressive strength and flexural strength of 36.35 MPa and 15.66 MPa, respectively, after 28 days. Furthermore, the concentration of heavy metals in the mortar was within the standard specified by the National Environmental Board's notification.Keywords: มอร์ตาร์; เส้นใยแปรใช้ใหม่; ขยะแผงวงจรพิมพ์; สมบัติทางวิศวกรรม; การนำความร้อน; Mortars; Recycled fiber; Waste printed circuit board; Engineering properties; Thermal conductivit

พฤติกรรมของมอร์ต้าเสริมเส้นใยเหล็กภายใต้แรงระเบิดBehaviors of Steel Fiber Reinforced Mortar Subjected to Blast Impaction

ความเสียหายที่เกิดขึ้นจากการก่อการร้ายเป็นสิ่งที่ไม่สามารถคาดการณ์ได้ ในจังหวัดชายแดนใต้ของประเทศไทยได้เกิดความขัดแย้ง และความรุนแรงมาตั้งแต่ พ.ศ. 2547 จนถึงปัจจุบัน ทำให้มีการสูญเสียที่ไม่สามารถประเมินค่าได้ เหตุการณ์ส่วนใหญ่เกิดจากการกราดยิงและใช้วัตถุระเบิดซึ่งทำให้มีผู้บาดเจ็บและเสียชีวิตเป็นจำนวนมากเนื่องจากไม่มีที่กำบังหรือที่หลบภัยที่สามารถป้องกันได้ ดังนั้นโครงสร้างที่สามารถป้องกันกระสุนและระเบิดจึงเป็นสิ่งสำคัญในการป้องกันความเสียหายเหล่านี้ งานวิจัยนี้จึงมีเป้าหมายในการปรับปรุง และเพิ่มประสิทธิภาพในการต้านทานแรงระเบิดของผนังมอร์ต้า โดยใช้เส้นใยเหล็กชนิดปลายงอ ปริมาณร้อยละ 2 โดยปริมาตร เพื่อศึกษาความสามารถและพฤติกรรมในการต้านทานแรงระเบิด จึงทำการทดสอบด้วยระเบิด TNT ขนาด 0.5 ปอนด์ ที่ระยะปรับทอน เท่ากับ 0.55 0.65 และ 0.75 ผลการทดสอบพบว่า มอร์ต้าเสริมเส้นใยเหล็กมีประสิทธิภาพในการต้านทานแรงระเบิดได้ดีกว่ามอร์ต้าธรรมดาในทุกกรณี โดยจากความเสียหายที่เกิดขึ้นนั้นบ่งชี้ว่ามอร์ต้าธรรมดาเกิดการวิบัติที่มีความรุนแรง และเสียหายโดยเกิดเป็นรอยร้าวขนาดใหญ่บริเวณกึ่งกลางผนัง แตกต่างกับมอร์ต้าที่มีเส้นใยเหล็กที่สามารถช่วยกระจายแรงและยึดรั้งรอยแตกร้าวทำให้เกิดความเสียหายลดลงจนกระทั้งแทบไม่เกิดความเสียหายใดๆ อีกทั้งยังมีความสามารถในการรับกำลังหลังจากรับแรงระเบิดได้สูงกว่ามอร์ต้าธรรมดาได้อีกด้วยDamages caused by terrorism are unpredictable. Since 2004, conflicts and violence have occurred in southern Thailand causing invaluable loss. Most of the incidents were mass shootings and explosives which resulted in many injuries and deaths due to the lack of defensible cover or shelter. Therefore, the bullet and explosions proof structures are essential for preventing damages in these events. This research aims to improve and enhance the efficiency of explosion resistance of mortar walls using the hookedend steel fiber as 2% by volume. For comparison in behavior and effectiveness, the steel fiber reinforced mortar (SFRM) specimens which subjected to 0.5 lb TNT with varied scaled distance (Z) of 0.55 0.65 and 0.75 were investigated. The experimental results showed that the SFRM had better explosion resistance performance than the plain mortar for all cases. Due to the force distribution and crack retention of fiber, the SFRM was shown in less damaged than the plain mortar that occurred violent damages and cracks at the center of the specimen. In addition, the strength after the explosion event or residual strength of SFRM was also found higher than that of the plain mortar

Use of Cement Mortar Incorporating Superabsorbent Polymer as a Passive Fire-Protective Layer

Concrete structures, when exposed to fire or high temperatures for a certain time, could suffer partial damage or complete structural failure. Passive fire-protective coating materials are an alternative way to prevent or delay damage to concrete structures resulting from fire. Superabsorbent polymer (SP) is a synthetic material known for its ability to absorb and retain a large volume of water within itself. With this unique property, the SP exhibits great potential for use as a passive fire protection material. Although several studies have been carried out to investigate the effect of SP as a surface coating material for fire protection, very few have been investigated on the potential use of SP mixed with mortar as a passive fire-protective layer. The objective of this study is to introduce the use of SP in plastering mortar as a fire-protective layer for concrete subjected to temperatures up to 800 °C. This study is divided into two parts: (1) investigating the properties of cement mortar mixed with SP at 0.5% (CONC/SP-0.5) and 1.0% (CONC/SP-1.0) by weight of cement, and (2) investigating the potential use of SP mortar as a plastering layer for concrete subject to high temperatures. The experimental results showed that the density and compressive strength of SP mortar decreases with increasing SP dosages. From the heat exposure results, SP mortar exhibited lower strength loss due to the ability to mitigate moisture through its interconnected pore system. As for the use of SP mortar as a plastering layer, the results demonstrated the concrete specimen plastered with SP mortar had a lower temperature at the interface and core than that plastered with plain mortar. This led to a reduced strength loss of 20.5% for CONC/SP-0.5 and 17.2% for CONC/SP-1.0