Repair and rehabilitation of concrete pavements Indireddy
This paper provides an overview of the current methods of analysing and repairing cracks in concrete pavements. The Finite element method (FEM) models and non-destructive analysis method, and the repairing methods using electro-deposition, electro chemical, recycled steel fibres are reviewed.
Estimation of Critical Stress in Jointed Concrete Pavement
Pavements are subjected to repeated traffic loads along with temperature variation throughout their service life. In concrete pavement, critical stresses are developed due to the combined effect of wheel load and positive temperature differential leading to initiation of cracks. In this paper, a methodology has been presented for evaluating the critical stress in concrete pavement based on finite element technique. A generalized expression for estimating the critical stress has been developed considering various combinations of pavement configurations, axle loads and temperature differential. This equation can be effectively utilized to obtain the critical stress in concrete pavement for any combination of axle load and nonlinear positive temperature gradient without performing a rigorous finite element analysis. Based on the generalized expression, a modification on Bradbury's temperature stress coefficient (C) has been suggested.
The Analysis on Fire Smoke Exhausting Robot Vibration Based on Wavelet Transform
Belt relaxation, which affects a lot on operation reliability of the fire smoke exhausting robot, is hard to detect. In this paper, a new method for belt relaxation feature recognition based on continuous wavelet transform (CWT) is proposed, and a vibration model which simplified the robot as a 2-dof forced vibration system under harmonic excitation is established. The vibration acceleration signal has been collected using the IEPE sensor and data acquisition card, experimental results verified the accuracy of the vibration model, and weak impact signal caused by the belt relaxation was distinguished, that testify the practicability of the CWT method in belt relaxation feature recognition.