The Potential Use of Ceramic Waste Sludge as a Supplementary Cementitious Material

Cement based materials (CBM) are among the most common construction materials in the world. The most common form of CBM is concrete. One advantage of the material is that it can be produced locally, reducing transportation and... [ view full abstract ]

Cement based materials (CBM) are among the most common construction materials in the world. The most common form of CBM is concrete. One advantage of the material is that it can be produced locally, reducing transportation and energy costs. However, the use of raw materials in the production of both cement and aggregates carries an environmental cost.
Due to its prominence in use, design and construction of concrete structures is governed by a plethora of codes of practice and design guides. These codes of practice generally classify CBM according to their strength class only and are restrictive on the CBM constituents. However, there is increasing desire to supplement or replace some of the raw materials used in producing CBM, while jointly reducing the amount of waste material being sent to landfill.
In this context, the authors have examined the potential use of ceramic waste sludge (CWS) as a supplementary cementitious material. CWS is a waste product, generated in the pharmaceutical industry, which at present is sent to landfill or exported for recycling in continental Europe. However, the constituents of the ceramic material suggest that it may possess pozzolanic properties, which could be of benefit in replacing Portland cement in concrete.
This paper presents the results of a series of characterisation tests to determine any pozzolanic or other pertinent properties of the material. Results show that use of the CWS as a partial cement replacement in certain applications may be possible and that pozzolanic reactions may occur at later stages, with other effects on the hydration process evident in earlier parts of the curing process.