Correlation between the Compressive, Tensile Strength of Old Concrete under Marine Environment and Prediction of Long-Term Strength

Weilai Yao,Wei Fei,Shiyong Jiang,Tao Cai

doi:10.1155/2017/8251842

Weilai Yao, Wei Fei + Show 2 more

Open Access

https://doi.org/10.1155/2017/8251842

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Abstract

Compressive strength and tensile strength are important mechanical properties of concrete. The long-term strength of concrete under real service environment is an important parameter when evaluating existing buildings, which should also be properly considered in structural design. In this study, the relationship between compressive and splitting tensile strength of old concrete existing for long period under marine environment was investigated. At a deserted harbour, concrete cores samples were drilled by pairs in site. For each pair of samples, the two cores were drilled from the adjacent location and conducted to compressive, splitting tensile test, respectively. 48 compressive and splitting tensile strengths were finally obtained. From the test results, tensile strength presents general uptrend with compressive strength, and the two parameters are well positively correlated. Exponential model generally recommended by building codes or literatures is still capable of describing the relationship between compressive and tensile strength of old deteriorated concrete, when function parameters are properly determined. Based on statistical theory and the experimental result of this study, a method for predicting long-term tensile strength of concrete is developed and an example is given, which may provide a potential way to estimate long-term concrete strength under real marine environment.

Highlights

The value of tensile strength of concrete affects the performance of structures, such as the shear force resistance and the load-bearing capacity of anchors with concrete cone failure as decisive failure mode
The real value of the in situ tensile and compressive strengths of concrete deteriorated under authentic service environments for long time provide a necessary basis for the evaluation of structures, especially for those, which have existed for long period already
The correlation coefficient between compressive and splitting tensile strength is 0.72, demonstrating that the two types of strength are still well positively correlated under environmental effects for long period of time

Summary

Introduction

The value of tensile strength of concrete affects the performance of structures, such as the shear force resistance and the load-bearing capacity of anchors with concrete cone failure as decisive failure mode. The concrete strength is considered as time invariant, when conducting structural design and calculation In this way, constructions should be completely reliable and the service life should be infinite, as long as R > S (R and S represent resistance and stress in broad sense) is satisfied in designing stage. There are only a few existing studies that investigated long-term environmental effects on concrete strength under real service conditions. The major thrust of this study is to obtain both compressive and tensile strengths of concrete under real marine environment for long period (up to 61 years) and identify the correlation between the two mechanical properties. After that, based on statistical theory and a compressive strength predicting model from literature, a tensile strength predicting method was established and a calculating example was provided for interpreting, which may offer a potential way to estimate long-term tensile strength of concrete under real marine environment

Experimental Program

Results and Discussion

Prediction of Long-Term Strength under Marine Environment

Conclusions and Prospects