Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - InnovaConcrete (Innovative materials and techniques for the conservation of 20th century concrete-based cultural heritage)

Teaser

The modern architecture is directly related to the obtention of Portland cement and reinforced concrete in the end of the 19th Century. It generated a complete revolution in construction techniques, promoting the use of fair-faced concrete during the 20th Century. In this...

Summary

The modern architecture is directly related to the obtention of Portland cement and reinforced concrete in the end of the 19th Century. It generated a complete revolution in construction techniques, promoting the use of fair-faced concrete during the 20th Century. In this context, it is easy to understand the evolution of concrete production showing an increase of nearly 1700% in 100 years. The common employment of fair-faced concrete, without coatings or paintings, increases its susceptibility to suffer decay. The earlier manifestation of most of the decay processes is the onset of nano-and micro-cracks that is followed by a significant decrease in mechanical performance. In addition to these phenomena, reinforced concrete is specially affected by the ingress of water containing pollutants, which may cause corrosion of the reinforcements. In addition, unlike other building materials, conservation methodologies for historic concrete reparation and long-term maintenance do not yet have been developed due to its little recognition as part of our Cultural Heritage. Thus, 20th Century historic concrete is currently at risk from a lack of appreciation and care. Some monuments have been lost and more are in danger.
InnovaConcrete project addresses all challenges previously raised because its ambitious plan is not only focused on the development of advanced materials and techniques for historic concrete conservation but also aiming to better understand, define, interpret and manage 20th century concrete Cultural Heritage for future generations. Thus, the first target of InnovaConcrete is the development of innovative solutions for preserving concrete. The optimization of the proposed solutions carry out by the use of theoretical tools (multi-scale modelling approaches) together with experimental tools (laboratory and in situ validation). The promotion of citizen awareness of 20th Century concrete-based Cultural Heritage is the second target. The third target of the project is the market uptake of the InnovaConcrete solutions.

Work performed

Seven innovative impregnation products especially designed to preserve the historic concrete have successfully developed. The synthesis of these new products has been guided by strong support of multi-scale modelling approaches. A new family of impregnation treatments, containing a silica oligomer, which are able of sealing micro and nano-cracks by producing calcium silicate hydrated (C-S-H) gel, responsible for the mechanical properties of cement paste, in situ, in the concrete structures, have been developed. The silica oligomer produces C-S-H gel by the polymerization of silanol groups with Ca+2 ions existing in the cement pore water.
A second step of the project was to integrate innovative performances to the C-S-H technology, producing multifunctional treatments. Firstly, corrosion inhibitors, avoiding corrosion of reinforced bars, were integrated in the impregnation products. Secondly, C-S-H technology products with superhydrophobic behaviour have been obtained.
InnovaConcrete has also explored the advantages to use cementitious coatings reinforced with halloysite nanotubes.
Finally, InnovaConcrete has investigated a biotechnology based approach to produce enzyme-assisted self-healing of damage concrete. Specifically, enzymes carbonic anhydrase has been inmobilized in light weight aggregate particles.
The validation of the InnovaConcrete materials and technique is now in progress at laboratory scale. Preliminary results demonstrating its suitable performance have been already obtained. This validation is developed in a total of 680 cement mortar specimens. In order to simulate the decayed conditions, the mortars were subjected to different decay processes. Complementary to this experimental study, a powerful multi-scale model simulating concrete degradation has been developed. This simulation tool is now employed to understand the degradation behaviours observed in the mortars aged in laboratory conditions. Understanding the decay process of the historic concrete is a crucial factor in the preservation treatments development.
The in situ validation of the InnovaConcrete materials on concrete structures will be developed in the second part of the project on seven concrete-base monuments. These case studies have been selected to cover a wide range of societal/economic impacts as well as to represent different environmental conditions and conservation problems.
Regarding to second target of InnovaConcrete, to promote awareness about concrete heritage. The first step consisted of the selection of the significant concrete-based monuments in Europe. A final selection of 100 monuments was made according to the adopted criteria. The complete information is available in an open platform (https://100of20.innovaconcrete.eu/).
In addition, a benchmark guidance document for the conservation of concrete heritage is being implemented. This document provides guidance for the conservation of concrete heritage with respect to its cultural, historical aesthetics and technological significance. A simple tool to help in the decision making process during historic concrete conservation is also developing according to the benchmark guidance.
On the other hand, different cultural, technical and scientific events have been programmed in the project to promote the citizen awareness. Three workshops have already been held in Madrid, Gijon and Roma around Torroja Building, Chillida sculpture and Nervi Stadium, respectively. Moreover, other cultural events, targeted for general public, were organized such as phographical exhibitions, contemporary dance exhibitions and contests. All these activities produced a huge expectation from the local media. Virtual tours around the case study with the possibility to get relevant information about the monuments have been also designed
Finally, according to the third target, the market uptake of the innovative solutions, an InnovaConcrete product has already launched to the market. Specifically, it is an

Final results

The InnovaConcrete project has applied nanoscience to develop advanced materials and techniques specifically designed for concrete heritage preservation. Impregnation treatments, producing, in situ, C-S-H gel, multi-purpose treatments giving rise to additional superhydrophobic or corrosion inhibiting performance and enzyme-assisted self-healing have been successfully developed.
Moreover, InnovaConcrete has thoroughly committed to the relevance of historic and artistic issues in “historic concrete” preservation. Thus, the study of criteria of the authenticity and the evaluation of the concrete-based CH are significant activities of the project. In recent years, many concrete masterpieces have already been demolished because they have not been considered to be elements of heritage. Therefore, InnovaConcrete works as watchdogs of concrete heritage. The project also promotes the creation of social-economic activities around “historic concrete”. In addition, a benchmark guidance for the conservation of concrete-based heritage is being carried out according to the InnovaConcrete results, and it will be implemented as a decision making process software to be employed during conservation interventions on historic concrete.

Website & more info

More info: http://www.innovaconcrete.eu.