Civil Engineering Departmental Seminar - Innovative Use of Alkali-Activated Slag in Cut-Off Wall Applications
Supporting the below United Nations Sustainable Development Goals:支持以下聯合國可持續發展目標：支持以下联合国可持续发展目标：
There has been a surge of interest in Alkali-Activated Slag (AAS) binders, particularly in concrete applications; however, their potential use in cut-off wall construction remains largely unexplored. This study investigates the feasibility of AAS binders as an alternative to conventional binders for such applications, focusing on their fresh properties, unconfined compressive strength (UCS), hydraulic conductivity, and chemical durability. A two-phase experimental program was conducted. Phase one involved a screening study using three activator dosages (AAS-1, AAS-3, and AAS-5), identifying the 5% activator dosage (AAS-5) as the most effective based on early strength development and setting behavior. Phase two compared four binder systems: Portland cement (G0), 40% slag cement (G40), 80% slag cement (G80), and AAS-5.
Results demonstrated that AAS-5 mixtures achieved comparable fresh properties to slag cement mixes and superior mechanical performance, with the highest 28-day UCS and the lowest hydraulic conductivity among all systems tested. Moreover, AAS binders exhibited excellent sulfate resistance, maintaining strength in aggressive chemical environments where Portland cement mixes showed varied behavior due to sulfate-induced pore filling. The enhanced performance of AAS mixtures is attributed to their denser microstructure and lower porosity. These findings support the viability of AAS binders as a sustainable and high-performance alternative to traditional cementitious materials in cut-off wall applications, warranting further research and development in this domain.
Dr. Chian Siau Chen, Darren is the Vice Dean of the College of Design and Engineering at the National University of Singapore (NUS). He also serves as Director of the Centre for Soft Ground Engineering and is an Associate Professor in the Department of Civil and Environmental Engineering.
At NUS, Dr. Chian is an avid researcher in sustainable geotechnical engineering. His work focuses on optimising cement usage in ground improvement and repurposing waste materials, such as dredged soft clays, industrial slag, and incinerated bottom ash, as supplementary cementitious binders and reclamation fill.
Dr. Chian plays an active role in the international geotechnical community. He is the Secretary of ISSMGE Technical Committee TC217 on Land Reclamation, and a nominated member of TC104 (Physical Modelling) and TC203 (Earthquake Engineering). Domestically, he serves as President of the Geotechnical Society of Singapore and chairs the National Technical Committee for Civil and Geotechnical Works.
His contributions have earned him numerous accolades, including recognition as one of Asia’s Top 10 Innovators Under 35 by MIT Technology Review, the Singapore Accreditation Council Distinguished Award, Singapore’s Prominent Geotechnical Engineer Award, the Minister’s Innovation Award, and the IAAM Scientist Medal.