Unexpected Transformations Reinforce Roman Concrete

Researchers used the Advanced Light Source (ALS) to study binding phases in Roman architectural concrete, revealing reactions and profound transformations that contribute to the material’s long-term cohesion and durability.

The findings add to our growing understanding of cementing processes in Roman concretes, informing resilient materials of the future.

Marie Jackson, a research associate professor at the University of Utah, has devoted much of her career to understanding the scientific mysteries underlying the exceptional durability of Roman concretes. The ALS has been essential to her and her colleagues’ studies, helping to reveal the chemical and microstructural evolution of the materials.

Concrete is made of rock aggregates and a binder. Modern concretes typically use Portland cement—made by burning a mixture of limestone and clay at high temperature—as binder. Roman concretes, in contrast, consist of coarse volcanic rock (or brick) aggregate bound with mortar made from hydrated lime and reactive tephra—the particles ejected from explosive volcanic eruptions.

In this study, Jackson, along with collaborators Admir Masic and Linda Seymour of the Massachusetts Institute of Technology and Nobumichi Tamura of the ALS, examined mortar samples from the Tomb of Caecilia Metella in Rome. The team hoped that the 2,050-year-old monument would provide insights into how Roman builders’ selections of reactive volcanic rock influenced the material characteristics of the very robust concrete.

Read more on the ALS website

Image: The Tomb of Caecilia Metella on the Via Appia Antica in Rome. The edifice is one of the most refined concrete and dimension stone structures of the latest Roman Republican era.

Credit: Emmanuel Brunner

The Middle East synchrotron officially opens MS beamline

The 8th of July 2021 marked the inauguration of SESAME’s Materials Science (MS) beamline. The Ambassador of Switzerland to Jordan, H.E. Mr. Lukas Gasser, along with members of his embassy team, and UNESCO’s Representative to Jordan, Ms. Min Jeong Kim, were welcomed to the inaugural ceremony by the Director General of SESAME, Professor Khaled Toukan, and the Directors of SESAME. 

In his welcoming remarks, Khalid Toukan pointed out that the beamline now allowed the users of SESAME to obtain diffraction data of a quality unparalleled in any laboratory in the region.

The MS beamline is heavily based on the MS X04SA beamline previously in operation at the Swiss Light Source, and its donation to SESAME by the Paul Scherrer Institute (PSI) has resulted in SESAME having a powerful and extremely precise tool to investigate matter at the micro-, nano- and atomic-scale.

A ribbon officially inaugurating the beamline was cut by H.E. Mr. Lukas Gasser and Professor Khaled Toukan, together with Ms. Min Jeong Kim.

Work on the MS beamline had started in 2015, with the adaptation of the design of the MS X04SA beamline to the characteristics of SESAME’s machine. In 2016, after receiving the donation of another major component, a detector from the Swiss company Dectris, execution of the project was fast-tracked, and the installation phase took place between 2017 and 2019, which is when SESAME received a diffractometer for the beamline as a donation from the Diamond Light Source. Upon sourcing the necessary equipment, the MS beam was first delivered to SESAME’s experimental station at the end of 2019. Fine tuning and characterization of its performance continued during the Covid-19 pandemic, and in December 2020, the beamline started hosting its first users. A first paper utilizing data taken at the MS beamline has already been published in a high-impact journal.

Read more on the SESAME website

Image: Cutting the ribbon of the MS Beamline (left to right): the Director General of SESAME, Professor Khaled Toukan, the UNESCO Representative to Jordan Ms. Min Jeong Kim, and the Ambassador of Switzerland to Jordan, H.E. Mr. Lukas Gasser   Note: all picture participants are Covid-19 Vaccinated.

Credit: © SESAME 2021

Synchrotron light reveals why modernist stained glass deteriorate

Stained glass is a fragile component of our Cultural Heritage since was used for the windows of buildings, and a large part of it is exposed to weathering and consequently to deterioration. The concern raised regarding the decay shown by the modernist enamelled glass has led the path to a long-term study and to the thesis presented today by Martí Beltrán González. “We are satisfied because totally new information have been obtained and, in particular, data that may help to better preserve the enamelled glass windows of this period ”, highlights Trinitat Pradell, director of the thesis.

Synchrotron light has important applications in the field of historical and artistic heritage and the Universitat Politècnica de Catalunya (UPC) group has been an ALBA user for years to carry out analyses for its research. In this case, the beamline where the experiments have been performed, MSPD, provides the use of microdiffraction technique. Stained glass samples cut into very thin sections (100 microns) have been analysed through X-rays to obtain high resolution diffraction patterns that give information about the chemical composition of the materials and enables the identification of the pigments and colorants used. The microstructure of the materials and the products formed as a result of corrosion can be detected too thanks to this synchrotron light technique.

Read more on the ALBA website

Image: Modernist stained glass from Museu d’Art de Cerdanyola (Les Dames de Cerdanyola) by L. Dietrich, 1888–1910, showing the characteristic green and blue enamels decay

Credit: Jordi Bonet