In the world of construction and infrastructure, concrete is the unsung hero, the backbone of countless structures that shape our cities and landscapes. But how do we ensure that the concrete we rely on is as strong as it needs to be, especially when dealing with existing structures? This is the question that Chenghui Wang, a researcher from the China Academy of Building Research and CABR Testing Center Co., Ltd., set out to answer in a recent study published in *Case Studies in Construction Materials* (translated as “建筑材料案例研究”).
Wang’s research delves into the critical parameter of concrete compressive strength, a key factor in the design and evaluation of existing concrete structures. The study highlights a significant issue: variations in international testing standards can lead to vastly different quality-assessment outcomes for similar projects. This discrepancy can have substantial commercial impacts, particularly in the energy sector, where the integrity of concrete structures is paramount.
The study systematically compares the concrete strength testing systems of China and Europe, focusing on two primary approaches: destructive testing (DT), such as core drilling, and non-destructive testing by calibration (NDTBC). Using data from 360 components rebound and 240 core specimens, with concrete strength grades ranging from C30 to C70, from eight large datasets of four Chinese typical projects, Wang established a comparable database through standardized processing.
“The discrepancy between Chinese and European standards is more pronounced in the NDTBC results than in the DT results,” Wang explains. The study found that both DT and NDTBC methods generally yield higher estimated strength values under Chinese standards than under European standards. For the eight datasets using the DT method, the mean difference was 2.3 MPa, representing 4.7% of the actual compressive strength. For the 24 datasets analyzed using the NDTBC method, the average difference was 4.7 MPa, 9.4% of the actual compressive strength.
This research sheds light on the economic and risk-aversion orientations of the two standards. “Overall, the Chinese standards show a strong economic orientation, while the European standards show a more stringent risk-aversion orientation,” Wang notes. This finding has significant implications for the energy sector, where the choice of testing standards can impact project costs, safety, and regulatory compliance.
The study’s findings could shape future developments in the field by promoting a more harmonized approach to concrete strength testing. As Wang’s research demonstrates, understanding and addressing the discrepancies between international standards can lead to more accurate assessments of concrete strength, ultimately enhancing the safety and longevity of our built environment.
In an industry where precision and reliability are paramount, Wang’s work serves as a crucial step towards bridging the gap between different testing standards, ensuring that the concrete structures we depend on are as strong and safe as they need to be. As the construction industry continues to evolve, this research could pave the way for more consistent and reliable testing methods, benefiting not only the energy sector but all industries that rely on concrete structures.