Sinthaworn Suppachai, Nimityongskul Pichai
School of Engineering and Technology, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand.
Waste Manag. 2009 May;29(5):1526-31. doi: 10.1016/j.wasman.2008.11.010. Epub 2009 Jan 7.
This article proposes a quick method of monitoring for pozzolanic reactivity of waste ashes by investigating the electrical conductivity of the suspension at an elevated temperature. This suspension is obtained by mixing tested pozzolan with an ordinary Portland cement (OPC) solution produced by mixing ordinary Portland cement with water. For comparison, silica fume, metakaolin, rice husk ash and river sand - whose pozzolanic reactivities range from reactive to inert - were used in the experimental investigation. The electrical conductivity of the suspension was continually recorded by using an electrical conductivity meter and stored by using a personal computer for a period of slightly over 1day. The indicative parameters that can be related to pozzolanic reactivity were discussed and analyzed in detail. It was found that it is possible to determine the pozzolanic reactivity of fly ash within 28h by using the proposed technique, as compared to 7 or 28 days for the determination of strength activity index according to ASTM. This technique would help concrete technologists to speedily investigate the quality of fly ash for use as a cement replacement in order to alleviate pollution caused by cement production and solve disposal problems of waste ashes.
本文提出了一种通过研究高温下悬浮液的电导率来快速监测废灰火山灰活性的方法。该悬浮液是通过将测试火山灰与由普通硅酸盐水泥和水混合制成的普通硅酸盐水泥（OPC）溶液混合而获得的。为了进行比较，在实验研究中使用了硅灰、偏高岭土、稻壳灰和河砂，它们的火山灰活性从活性到惰性不等。使用电导率仪持续记录悬浮液的电导率，并使用个人计算机存储略超过1天的时间。详细讨论和分析了与火山灰活性相关的指示参数。结果发现，与根据ASTM测定强度活性指数所需的7天或28天相比，使用所提出的技术可以在28小时内确定粉煤灰的火山灰活性。该技术将有助于混凝土技术人员快速研究用作水泥替代品的粉煤灰质量，以减轻水泥生产造成的污染并解决废灰的处置问题。
