Last edited 30 Nov 2016

Developments in cement products

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Contents

[edit] Introduction

Cement production has experienced significant development since it emerged some 2000 years ago. While the use of cement in concrete has a very long history, the industrial manufacturing of cements did not begin until the middle of 19th century with the development of chute kilns. These were later replaced by rotary kilns as the standard manufacturing equipment.

[edit] Development

While cement production has conventionally focused on Ordinary Portland Cement (OPC) composite and gustboiler slag cements, Portland pozzolanic cements and Portland limestone have also gained prominence, especially in areas where fly-ash or slag are not available.

Because of the global need to reduce CO2 emissions, and the drive for cost reduction, cement companies have attempted to lower the clinker content in their cements, although, there are limits which are given by cement performance. The decreasing of this clinker level in cement products is mainly taken into consideration in relation to the international accessibility of pozzolanic materials of industrial origin and latent hydraulic, a in particular there is a focus on cements products that have a high level of limestone content.This is essentially an extension of the present cement norms.

[edit] The requirement for new technologies

All cement products have to satisfy the basic requirements for strength development, durability, early strength development, cost, workability and environmental performance. Depending on the composition of the cement product, these requirements can be satisfied to different degrees. It lies with producers of these cements to optimise the differences in the types of products, and for the buyer to choose the suitable type for construction.

New cements products are likely to focus on durability capacity such as the penetration of chloride and carbonation resistance.

[edit] Future cements

There are a wide range of cement products available. Celitement for example, is founded on calcium silicate hybrid phases. Production is achieved by hydro-thermal mixture and by the reactive milling of lime in a silicon constituent. The Ca/Si ratio is lower when compared to OPC clinker, subsequently CO2 emissions and energy consumption might also be lower. However, it is presently too early to predict the future potential of these cements with respect to the production cost, strength or the practical potential for substitution of traditional cements.


Mark Long

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