No abstract

This paper presents the effect of nano silica, used individually and in combination with set accelerator or hydrated lime, on the properties of high volume fly ash (HVFA) cement composites, replacing 70 % of cement. Compressive strength test along with X-ray diffraction and thermogravimetric analysis were undertaken to study the effect of various elements on the physico-chemical behaviour and the pozzolanic activity of the blended samples. The addition of 5 % nano silica improved the 7 day strength of the blended sample by 76 % and by further increasing the nano silica content to 7.5 %, the 7 day strength increased by 94 %. However, at 28 days both 5 and 7.5 % nano silica modified samples showed approximately the similar improvement in strength i.e. 54 and 50 % respectively. With the addition of set accelerator to nano silica modified HVFA cement blend, there was a considerable reduction in both 7 and 28 day strengths. Addition of 5 % hydrated lime to HVFA blend, modified with 5 % nano silica showed no effect on the further improvement of strength. However, when 5 % hydrated lime was added to the 7.5 % nano silica modified HVFA blend, there was a considerable reduction in both 7 and 28 day strengths. This demonstrates that nano silica is highly effective in improving the strength of high volume fly ash cement blends when used alone, but when it is used in combination with either hydrated lime or set accelerator, shows no or negative effect on the development of strength.

No abstract

No abstract

The idea that water management should take an integrated approach has become the global paradigm over the past two decades. This new paradigm has come to be known by many different names. This paper explores the use, history and meaning of these competing terms, and discusses the possible implications of this term-proliferation. The literature indicates that a minimum of 26 distinct terms have been used. The use of different terms appears to have underwritten a belief that each term identifies a distinctly different field of study. After analysing sample definitions and subject areas for the eight most frequently used terms, it has been determined that some terms do have fundamental differences and others are essentially the same. This unnecessary term-proliferation contributes to a 'knowledge silo' effect, impeding knowledge-sharing and research advancement within the water management field. It is recommended that both academia and industry start actively considering term-proliferation when searching and publishing literature.