Abstract
The severe deterioration of a cement asphalt (CA) mortar layer may lead to the movement of the upper concrete slab and impair the safety of the speedy train. In this study, a test specimen simulating the structure of high-speed rail track slabs was embedded with delaminated cracks in various lateral sizes inside the CA mortar layer. Impact–echo tests (IE) were performed above the flawed and flawless locations. In present study, the IE method is chosen to assess defects in the CA mortar layer. Both traditional IE and normalized IE are used for data interpolation. The normalized IE are the simulated transfer function of the original IE response. The peak amplitudes in the normalized amplitude spectrum and the peak frequency in the traditional amplitude spectrum for the top concrete overlay were used to develop simple indicators for identifying the integrity of the CA mortar layer. The index was based on the difference of the experimental peak amplitude and frequency of the ones calculated from previously developed formulas for plates without substrates. As a result, the technique does not require an experimental baseline for the crack assessment. A field test and analysis procedure for evaluating high-speed rail slab systems are proposed.
Highlights
The cement–asphalt–mortar layer (CA mortar layer) is located between the upper pre-stressed concrete track slab and the base concrete roadbed
Structural cracks in concrete are detectable by the stress wave methods such as ultrasonic echo [9] or the impact–echo method (IE) [10,11], identifying cracks inside the cement asphalt (CA) mortar layer is rather difficult
Instead using the force–time function produced by the impactor to obtain to theobtain transfer function, modifiedthe of using the force–time function produced by the impactor the transferthe function, modified Rayleigh wave (R‐wave), which is the first arrived dominant displacement waveform shown as point A to C in Figure 3a, is served as the simulated force–time function [21,22,23]
Summary
The cement–asphalt–mortar layer (CA mortar layer) is located between the upper pre-stressed concrete track slab and the base concrete roadbed. Waves (MASW) methods are mainly chosen for assessing the layering thickness and properties [13,14,15,16,17,18,19]. The application these methods usually aims at assessing concrete with and surface damages[13–. The application of these methods usually aims at assessing concrete with surface with layer variation [20] and is more time consuming than the other conventional Non-destructed test damages or with layer variation [20] and is more time consuming than the other conventional Non‐
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