An Experimental Study Examining the Size Effect on the Compressive Dynamic Performance of Nuclear Power Containment Concrete

Furong Li,Hui Long,Guoxing Chen

doi:10.1155/2020/7582862

Abstract

To study the size effect of nuclear power containment concrete (NPCC) under compressive dynamic performance, the cube concrete specimens with 3 different cube sizes were measured at 10 different loading strain rates using a hydraulic servo, and the failure mode and compressive strength of NPCC were compared and analyzed under different loading conditions. Based on the comparative analysis of experiment results, the following conclusions can be drawn: the effect of loading strain rate has caused NPCC to develop from static strain rate, mainly cement cementitious layer damage and uniform distribution of cracks, to dynamic strain rate, where there are partial coarse aggregate failures and oblique cracks as the main crack distribution. Due to the size effect, the integrity of large-scale NPCC specimen after compression failure is relatively high. With the increase of loading strain rate and decrease of cube size, compressive strength of NPCC is gradually increased, and, with the increase of loading strain rate, the size effect on the mechanical properties of NPCC becomes more significant. Moreover, this paper quantitatively analyzes the influence of the coupling effect of strain rate and size effect on the compressive strength of NPCC, and its mechanism is discussed in depth. The research results are of great significance to the safety of nuclear power concrete containment.

Highlights

As a critical part of a nuclear power plant, containment structures are built with concrete materials
According to the compression experiments on nuclear power containment concrete (NPCC) specimens of 3 different cube sizes under 10 different loading strain rates, comparative analyses on the failure mode and compressive strength characteristic values of NPCC are conducted in order to understand the coupling of size effect and dynamic performance on NPCC. e main conclusions from the study are as follows: (1) For the concrete cubes of the same size, as the loading strain rate increases, the failure mode gradually develops from uniformly distributed cracks under the static loading strain rate to oblique cracks under dynamic loading strain rates
(2) As the loading strain rate increases, the compressive strength of the same concrete cube is gradually increased. ere is a linear relationship between the compressive strength dynamic coefficient and the dimensionless logarithmic value of the strain rate

Summary

Introduction

As a critical part of a nuclear power plant, containment structures are built with concrete materials. The scale-down model test is the most intuitive and suitable approach for engineering practices, especially for the study of dynamic performance This method is seriously affected by the size effect. While applying the scale-down model test to examine the nuclear power containment structure, the concrete specimens will be influenced by the coupling of size effect and dynamic performance. E present study conducts a series of experiments to consider the coupling of size effect and dynamic performance on NPCC by using concrete specimens with 3 different cube sizes and 10 different loading strain rates. En, according to the comparative analysis of failure modes and compressive strengths, the variation patterns of the concrete properties under the coupling of size effect and dynamic performance are analyzed from both qualitative and quantitative perspectives. The failure mechanism and mechanical performances of NPCC are discussed

Test Setup and Specimens

Analysis of Test Results

Findings

Conclusions