Feasibility of backfilling mines using cement kiln dust, fly ash, and cement blends

Cement kiln dust (CKD) is an industrial by-product of the cement manufacturing process, the composition of which can vary widely. Recent years of using alternative fuels have resulted in higher chloride and alkali contents within CKDs; as such, this limits the applications in which CKDs can be utilised. Using a CKD containing a high free lime content of 29.5%, it is shown that this CKD is capable of activating pulverized fuel ash (PFA) due to its high alkalinity, which can be utilised in low strength un-reinforced applications. One potential application involves the backfill of mines, reducing the need for continuous maintenance of the mine. This study focuses on the compressive strength achieved by various blends of CKD, PFA, and cement. Samples were hand mixed and compacted in 100 mm x 50 mm diameter cylinders, and unconfined compressive strength measurements taken at 28 and 56 days. The hydration products were assessed through the use of x-ray diffraction and thermogravimetric analysis. Aiming to maximise the use of CKD at a water to binder (w/b) ratio of 0.2, it was found that the maximum CKD content possible to achieve the required strength was 90% CKD blended with 10% cement

An Exploratory Review of the Design Literature: Gaps and Avenues for Future Research

The importance of design has been recognised by scholars from different fields such as artificial sciences and engineering, innovation, arts and creativity and management. Despite a shared understanding of the role of design as a potential enabler of innovation, it still acknowledges a wide range of meanings for two main reasons: the differing motivation underpinning a design project (from purely artistic to purely engineering, problem-solving) and the types of knowledge design can rely on (e.g., rational and calculative knowledge for engineering designers; subjective and expressive knowledge for graphic designers). It appears difficult to draw boundaries within the design field and identify a criterion for a clear-cut differentiation, yet most of the available definitions seem to share three attributes: design may refer to a process, which is goal-oriented; and the set of goals consists of solving problems, improving situations, or creating something new. The paper reviews the extant design literature and contributes to it by providing a structure for a deeper understanding of design. It emphasises: (i) the passage design has undergone from as expressing certain product specifications to being an important tool that can shape firms' strategy, and (ii) the extent to which both organisational and institutional factors have contributed to this process. It concludes by identifying the gaps within the literature that deserve further attention