4 research outputs found
Properties of one-part geopolymer pedestrian blocks made using 100 % waste materials
No full textOrdinary Portland Cement (OPC) is one of the most commonly used construction materials. However, the production process of OPC significantly contributes to environmental degradation, underscoring the urgent need for sustainable alternatives that can reduce the construction industry's carbon footprint. One such alternative is geopolymer concrete. This study focuses on the development of pedestrian blocks made from one-part geopolymer concrete, using 100 % waste materials such as fly ash, slag, and recycled asphalt aggregates. Additionally, recycled plastic was incorporated in varying proportions of 0.5 %, 1 %, and 1.5 % by volume of the binder materials. The physical and mechanical properties of the geopolymer concrete blocks—including density, water absorption, abrasion resistance, skid resistance, compressive strength, and flexural strength—were thoroughly investigated. Given the focus on waste material utilization, assessing the environmental impact is essential. The Global Warming Potential (GWP) was selected as a key metric to evaluate the carbon footprint (measured in kg CO₂-equivalent) of the materials used in the geopolymer pedestrian blocks. Results indicated that although mechanical strength decreased with increasing plastic content, the blocks maintained adequate strength for pedestrian use up to a certain percentage of plastic incorporation. In terms of GWP, the inclusion of plastic waste led to a slight increase; however, the overall GWP of the blocks remained low due to the use of waste materials. This paper discusses the effect of recycled plastic on the tested properties, and the results indicate that one-part geopolymer concrete blocks can be effectively used for pedestrian applications, meeting standard requirements with the inclusion of plastic up to a specific volume
Parametric and feasibility investigation on drone-assisted placement of self-compacting lightweight concrete
No full textThis study investigates the feasibility of drone-assisted concrete placement using self-compacting lightweight concrete (SCLC), with an emphasis on enhancing construction efficiency, safety, and accessibility in challenging environments. The research comprises two main components: (1) the development of an optimized SCLC mix suitable for aerial placement, and (2) a parametric evaluation of drone performance in transporting and pouring concrete under varying operational conditions. The optimized SCLC mix, containing 400 kg/m³ of cement and 8 % superplasticizer, achieved a slump flow of 660 mm, T50 time of 4.8 s, and compressive strength of 26.8 MPa, satisfying EFNARC criteria. Drone-based experiments assessed flight energy, pouring time, and mechanical properties across multiple payloads, flowabilities, drop heights, and wind speeds. Results indicate that flying energy increases by 17.4 % per kilogram of payload, while unit energy for concrete pouring is estimated at 1.775 Wh/kg. Concrete flowability significantly affects pouring time, with improved flow reducing energy and time consumption. Additionally, higher drop heights and wind speeds were found to increase splash dispersion, affecting placement precision. Mechanical testing revealed a slight reduction in compressive and flexural strengths for drone-cast specimens—6.6 % and 12.2 % lower, respectively—compared to conventional casting, highlighting minor challenges in precision placement. Despite these limitations, the findings confirm the technical feasibility of drone-assisted SCLC placement at laboratory scale and identify key operational parameters influencing performance. This study contributes to the emerging field of aerial robotics in construction, offering a foundation for future development of automated, drone-based concrete placement in remote or hazardous environments
Role of Slag Replacement on Strength Enhancement of One-Part High-Calcium Fly Ash Geopolymer
Get PDFThis paper reports the effect of slag (SL) replacement and water-to-binder (w/b) ratio on properties of one-part geopolymer derived from high-calcium fly ash (FA) and sodium silicate powder (NP). The FA was replaced by SL at the rates of 20% and 40%, respectively. This study focused on conducting experimental tests to evaluate the relative slump, setting time, compressive strength, and flexural strength of one-part FA-based geopolymer. The relationship between compressive and flexural strengths of one-part geopolymer mortar was expressed using the simplified linear regression model whereas the normalization of compressive and flexural strengths with SL replacement by the strength of one-part geopolymer mortar without SL as the divisor was also evaluated. Experimental results showed that the increasing of SL replacement and w/b ratio significantly affected the workability and strength development of one-part geopolymer mortar. Higher SL replacement exhibited a positive effect on their compressive and flexural strengths; however, a reduction in its setting time was obtained. The enhancement in strength development of one-part geopolymer was primarily due to the increased calcium content of SL. Similarly, reducing w/b ratio in the production of one-part geopolymer resulted in a decrease in setting time and an increase in strength development. Based on the relationship between compressive and flexural strengths, the prediction coefficient value (R2) obtained from the curve fitting procedure was 0.835, indicating a good level of reliability and acceptability for engineering applications
ผลกระทบของนาโนแคลเซียมคาร์บอเนตต่อสมบัติของคอนกรีตมวลเบาและสมบัติการพิมพ์ของมอร์ตาร์สำหรับงานพิมพ์ 3 มิติEffect of Nano-Calcium Carbonate on Lightweight Concrete Properties and Printability of Mortar of 3D Printing Application
No full textงานวิจัยนี้ศึกษาผลกระทบของนาโนแคลเซียมคาร์บอเนตต่อสมบัติของคอนกรีตมวลเบาและสมบัติการพิมพ์ของมอร์ตาร์สำหรับงานพิมพ์ 3 มิติ โดยแปรผันปริมาณของนาโนแคลเซียมคาร์บอเนตในส่วนผสม ตั้งแต่ 0–4% ของน้ำหนักซีเมนต์ ทำการทดสอบสมบัติของคอนกรีตมวลรวมเบา ได้แก่ ค่าการยุบตัว ระยะเวลาก่อตัว หน่วยน้ำหนักคอนกรีต การซึมผ่านของน้ำกำลังรับแรงอัด องค์ประกอบเคมีและโครงสร้างจุลภาค รวมถึงสมบัติด้านของงานพิมพ์ 3 มิติ ได้แก่ ทดสอบการไหลแผ่ ระยะเวลาเริ่มต้นพิมพ์ และกรอบเวลาในการพิมพ์ ผลการทดลองพบว่า การเพิ่มขึ้นของปริมาณนาโนแคลเซียมคาร์บอเนต ส่งผลให้ค่าหน่วยน้ำหนักมีแนวโน้มเพิ่มขึ้น ในทางกลับกันค่าการยุบตัวและระยะเวลาการก่อตัวของคอนกรีตนั้นลดลง ในส่วนของค่ากำลังรับแรงอัดพบว่า เมื่อปริมาณแคลเซียมคาร์บอเนตเพิ่มขึ้นส่งผลให้ค่ากำลังรับแรงอัดเพิ่มขึ้น จนถึงปริมาณนาโนแคลเซียมคาร์บอเนตที่ 2% โดยน้ำหนักซีเมนต์จากนั้นมีแนวโน้มลดลง และ ค่าการซึมผ่านน้ำของคอนกรีตที่มีแนวโน้มลดลงตามปริมาณแคลเซียมคาร์บอเนตที่เพิ่มขึ้นจนถึง 2% โดยน้ำหนักซีเมนต์จากนั้นมีแนวโน้มกลับมาเพิ่มขึ้น ซึ่งมีผลยืนยันการเพิ่มขึ้นของนาโนแคลเซียมคาร์บอเนตด้วย XRD และ การเติมเต็มในช่องว่างด้วย SEM ในส่วนของงานพิมพ์ 3 มิติ พบว่า ระยะเวลาเริ่มต้นในการพิมพ์และความกว้างของเส้นพิมพ์ลดลง เมื่อเพิ่มปริมาณนาโนแคลเซียมคาร์บอเนตThis research investigated the effect of nano-calcium carbonate on lightweight concrete's properties. The amount of nano-calcium carbonate was varied from 0–4% by weight of cement. Experimental series included slump test, setting time, unit weight, water permeability, compressive strength, chemical composition, and microstructure. In terms of the properties of 3D printing, the focus points were flow test and open time. The results show that the unit weight increased with an increase in nano-calcium carbonate content. However, the slump and setting time were found to decrease with an increasing amount of nano-calcium carbonate. In respect of compressive strength, it was found to increase with the increasing calcium carbonate content up to about 2%, and then decreased. The water permeability also decreased with the increasing nano-calcium carbonate content up to about 2%, then increased. The increase of nano-calcium carbonate content by XRD and the void filling by SEM were observed. In terms of 3D printing, the initial printable time and width of the printed filament decreased with an increase in nano-calcium carbonate content
