題目：The Potential of Microwave Curing for Manufacturing Low-carbon Concrete

報告人：Dr. Yun Bai (University College London)

時間：2017年5月26日(周五)10:00 AM

地點：明故宮校區(qū)A18-529

主辦單位：國際合作處、科協(xié)、航空宇航學院

報告人簡介：

    Dr Yun Bai received his BS in 1993 from Chongqing University, Chongqing, China and MS in 2004 from University of Ulster, Belfast, U.K. and PhD in 2004 from Queen’s University Belfast, Belfast, U.K.. He is currently Reader in Materials and Head of Geotechnics & Materials Section, Department of Civil, Environmental & Geomatic Engineering, University College London, U.K.. Main research areas: with a research grant portfolio of over ￡6Million, Dr Bai’s research covers a wide range of construction material science and engineering, including: novel cementitious materials, durability of concrete structures and nuclear waste immobilisation using cement systems. With more than 100 research papers published in the above areas, Dr Bai’s work has been well-received by academia and industry. He is the member of RILEM, MICT, IoM3, FHEA, et al.

報告摘要：

Steam curing is widely adopted by construction industry to facilitate the development of early strength of concrete. Although it can shorten the curing duration and provide economic benefits, it may lead to thermal stress inside the large or thick concrete products due to non-uniform heating. Moreover, it is not environmentally friendly due to its high energy consumption. Different from steam curing which is dependent on thermal conduction, microwave heating relies on energy conversion, which can result in fast volumetric heating. In this presentation, ongoing research on developing an intelligent microwave system for manufacturing concrete products is introduced. The key features of this microwave system include using optical fibre Bragg grating (FBG) sensors to control the temperature and the humidity inside concrete and microwave oven cavity, respectively. Using this tailored-made microwave system, research is ongoing in the Advanced and Innovative Materials (AIM) Group at University College London to explore the potential of curing two types of low-carbon cementitious systems, namely high-volume fly ash (HVFA) and alkali-activated fly ash (AAFA). In both systems, thermal curing is essential for the strength development, in particular, early strength development. The results indicated that even with 55% of Portland cement (PC) replaced by fly ash, the compressive strength of HVFA concrete can achieve 20MPa after only 8-hour’s microwave curing. In the case of AAFA system where 100% fly ash is activated by NaOH without using PC, a 42MPa compressive strength can be reached within 6 hours’ microwave curing, which compared to the 41 MPa compressive strength achieved after 24 hours’ thermal oven curing at 85oC, representing an 18-hour reduction of curing duration and 73% saving of energy consumption. Based on the results obtained so far, the potential of this innovative microwave curing technique for future precast concrete manufacture is then discussed.