Cement and Concrete: From the Romans to Mars
Luca Valentini, Maarten Broekmans, Jan Elsen, and Ruben Snellings - Guest Editors
Table of Contents
Portland cement represents an essential commodity in a developing and quickly urbanizing world. However, the downside of its popularity is a massive ecological footprint, in terms of global warming potential and consumption of mineral and water resources. Therefore, the development of sustainable alternatives to ordinary Portland cement constitutes a fundamental technological and societal challenge. In this context, mineralogy and geochemistry play an important role in assessing primary and secondary resources for a new generation of cement and concrete that has a reduced ecological footprint, drawing from the knowledge of both ancient and modern binders. Mineralogical and geochemical tools are also essential to establishing a link between the basic physical and chemical processes that occur during the production, hardening, service life, and degradation of concrete.
- Cement and Concrete—Past, Present, and Future
- Historic Concrete Science: Opus Caementicium to “Natural Cements”
- The Rise of Portland Cements
- Alternative Non-Portland Binders
- Polarization-fluorescence Microscopy in the Study of Aggregates and Concrete
- Sustainable Sourcing of Raw Materials for Construction: From the Earth to the Moon and Beyond
Cement and Concrete—Past, Present, and Future
Historic Concrete Science: Opus Caementicium to “Natural Cements”
The history of mineral components in cementitious materials begins with clays and bitumen in the most ancient mortars, followed by gypsum- and lime-based plasters, mortars, and concretes. Romans perfected the fabrication of extremely durable mortars that form the basis of audacious architectural monuments in Rome, massive harbor constructions, and water-proofed cisterns in the Mediterranean region. During the industrial revolution, “natural cements” were developed through the burning of impure limestone or Si- and Al-bearing materials blended with pure limestone. Delving into the past of concrete science and the composition, durability, and resilience of historic binders, mortars, and concretes can inspire the development of modern environmentally friendly cementitious materials.
The Rise of Portland Cements
Alternative Non-Portland Binders
By Theodore Hanein, Angeles G. De la Torre, Zuhua Zhang, and John L. Provis
Polarization-fluorescence Microscopy in the Study of Aggregates and Concrete
By Maarten A.T.M. Broekmans, Isabel Fernandes, Ola Fredin, and Annina Margreth
Concrete structures may develop deleterious damage, which significantly reduces service life, structural integrity, and safety, posing serious issues in large or otherwise critical infrastructure. Routine petrographic assessments, including microstructure, texture, and fabric, of concrete and its (gravel and sand) aggregate and binder constituents in thin section using polarization-fluorescence microscopy (PFM) enables the unequivocal identification of features that would otherwise remain hidden in conventional petrography. Rigorous preparation procedures preserve original microstructural details, make preparation artefacts recognizable, and ensure that the fluorescent emission can be quantified. This contribution outlines the preparation of fluorescence-impregnated thin sections and elaborates on the application of PFM to damaged concrete, with further examples from selected rock types commonly used for concrete aggregate.
Sustainable Sourcing of Raw Materials for Construction: From the Earth to the Moon and Beyond
Each year, nearly 40 billion tonnes of raw materials extracted from the Earth’s crust feed into the construction industry. The associated material flows dramatically contribute to anthropogenic CO2 emissions. Therefore, more sustainable supply chains must be envisaged based on the use of locally available resources and the principles of circular economy. Drawing inspiration from vernacular architecture, innovative solutions for green construction based on sustainable exploitation of local resources can be posited. This strategy has also inspired the proposed practice of in situ resource utilization on planetary bodies such as the Moon and Mars.