Performance of patch repairs on historic concrete structures: a preliminary assessment

Ana Paula Arato Gonçalves,Susan Macdonald,Myriam Bouichou,Chris Wood,Élisabeth Marie-Victoire,M.G Grantham,C Mircea

doi:10.1051/matecconf/201928907001

Abstract

Carrying out patch repairs to historic concrete buildings and structures needs to be done carefully if their cultural value and significance is to be maintained. This often means repairs using custom designed materials and mixes for compatibility with the original concrete, and with great care paid to good workmanship. But with most repairs, commercial mixes are used which are not compatible with the host concrete but are justified because they adhere well, cure quickly and require limited skills to implement. A research collaboration has been established to test the performance of both approaches. The Performance Evaluation of Patch Repairs on Historic Concrete Structures (PEPS) began in 2018 and is a collaboration between the Getty Conservation Institute, Historic England and the Laboratoire de Recherche des Monuments Historiques. Its purpose is also to better understand key design and specification parameters and application methods. The research is based on assessing case studies in USA, England and France within a variety of climatic and environmental conditions, typologies and repair materials. This paper will present the methodology adopted to evaluate the repairs in the first phase. This will also include historical research on the specification and application of the repairs, preliminary field assessment and some testing.

Highlights

As the building stock of the 20th century ages, more examples from that era are being appreciated and identified as culturally significant. With this recognition comes a need for well understood repair strategies that better meet some of the typical principles applied to work on historic buildings and a body of practitioners who are able to specify and undertake this work
The rapid development of reinforced concrete construction over the 20th century means that much of this concrete heritage, carefully designed and built, did not benefit from the current level of knowledge about material behavior and durability that contemporary construction employs. Some of these structures were repaired at an early stage, bolstering the parallel development of the concrete repair industry
The fundamental difference between concrete conservation and concrete repair is that any work targeting historic structures must prioritize the need to preserve its cultural significance [1]

Summary

Introduction

As the building stock of the 20th century ages, more examples from that era are being appreciated and identified as culturally significant. The rapid development of reinforced concrete construction over the 20th century means that much of this concrete heritage, carefully designed and built, did not benefit from the current level of knowledge about material behavior and durability that contemporary construction employs. Some of these structures were repaired at an early stage, bolstering the parallel development of the concrete repair industry. Though concrete conservation is a discrete subsection of the much larger concrete repair industry, it is still in its infancy and there remains much work to be done to adequately equip this nascent field with the knowledge and skills to meet the growing demands

Challenges in conserving historic concrete

Planned outcomes from the research and next steps

Champs-SurMarne