Raman spectroscopy of cementitious materials

Recent advances in Raman spectrometers, resulting in faster acquisition times and the use of lower powered lasers have led to a resurgence in the application of Raman spectroscopy to the study of cementitious materials. However, despite it being widely believed that we know all about these materials, modern cements are extremely complex, heterogeneous materials. Given their complexity, and the widespread application of cement and concrete in today’s society, modern research into cement and concrete is truly multidisciplinary, with experts from the fields of chemistry, geology, mineralogy, materials science, corrosion science, engineering, even biology and medical science all investigating the structure and behaviour of cementitious materials. This review aims to look at the development of Raman spectroscopy as applied to the field of cement science. Starting with a historical overview, it then considers the spectra of cements at different stages in their lives, from fresh anhydrous materials, to hydrating and hydrated pastes, through to their degraded state. Whilst being concerned primarily with Portland cements, some alternative cementitious materials are also discussed, as are some of the additional materials found in modern cements and concretes; such as admixtures, cement replacement materials and reinforcement steel. However, it is not concerned with aggregates added to concrete, since this would be huge undertaking and would detract from the true focus of the review. Finally, the article identifies gaps in our current understanding and offers suggestions for potential future developments in the field.