The cement industry is facing numerous challenges in the 21st century due to depleting natural fuel resources, shortage of raw materials, exponentially increasing cement demand and climate linked environmental concerns. Every tonne of ordinary Portland cement (OPC) produced releases an equivalent amount of carbon dioxide to the atmosphere. In this regard, cement manufactured from locally available minerals and industrial wastes that can be blended with OPC as substitute, or full replacement with novel clinkers to reduce the energy requirements is strongly desirable. Reduction in energy consumption and carbon emissions during cement manufacturing can be achieved by introducing alternative cements. The potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies. Seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed. The study provides a comprehensive analysis of options for future cements, and an up-to-date summary of the different alternative fuels and binders that can be used in cement production to mitigate carbon dioxide emissions. In addition, the practicalities and benefits of producing the low-cost materials to meet the increasing cement demand are discussed.
The multiphasic conductive admixtures like macro steel fiber (SF), nano carbon black (NCB) and carbon fiber (CF) are incorporated into concrete to improve the conductivity and mechanical properties. In this study, the mechanical and conductive properties of the concrete beam are explored by the hybrid use of different conductive admixtures. The deflection hardening (multiple cracking) behavior of concrete beam with different fiber content, monitoring of single and multiple cracks of diphasic (SF+NCB) and triphasic (SF+CF+NCB) conductive concrete beam through resistance measurement is investigated. Moreover, the relationship between fractional change in resistance (FCR) and crack opening displacement is established to study the influence of different types and amounts of electric conductive admixtures on self-sensing behavior of concrete beam. Results reveal that the deflection hardening (multiple cracking) behavior is obtained with 70 kg m −3 SF content. The single and multiple cracks monitoring is illustrated through load-time and FCR-time relationship. In addition, FCR improved linearly with an increment of NCB with triphasic conductive admixtures.
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