General Optimal Trajectory Planning: Enabling Autonomous Vehicles with the Principle of Least Action

This study presents a general optimal trajectory planning (GOTP) framework for autonomous vehicles (AVs) that can effectively avoid obstacles and guide AVs to complete driving tasks safely and efficiently. Firstly, we employ the fifth-order Bezier curve to generate and smooth the reference path along the road centerline. Cartesian coordinates...

Restraining effect of aggregates on autogenous shrinkage in cement mortar and concrete

Shrinkage-induced cracking can impair the durability of concrete structures. In the past few decades, this topic has drawn more and more attention. Shrinkage of mortar and concrete is actually the result of the interaction between the shrinking cement paste and the non-shrinking aggregates. In recent years, different models that consider the...

Effect of supplementary materials on the autogenous shrinkage of cement paste

In recent years more and more attention has been given to autogenous shrinkage due to the increasing use of high-performance concrete, which always contains supplementary materials. With the addition of supplementary materials-e.g., fly ash and blast furnace slag-internal relative humidity, chemical shrinkage and mechanical properties of...

Examining the “time-zero” of autogenous shrinkage in high/ultra-high performance cement pastes

The term “Time-zero”, i.e., the time for the start of autogenous shrinkage measurement, is usually used for estimating the cracking potential of structural components. Accurate determination of the “time-zero” is therefore critical for autogenous shrinkage measurement, which is the main objective of this study. There is a general agreement...

New insights into autogenous self-healing in cement paste based on nuclear magnetic resonance (NMR) tests

The aim of this study is to investigate the effect of water migration from cracks into the bulk paste on autogenous self-healing. Nuclear magnetic resonance (NMR) technique was utilized to monitor water migration from cracks into the bulk paste during the process of autogenous self-healing. NMR results show that initially the water in the...

Numerical Studies of the Effects of Water Capsules on Self-Healing Efficiency and Mechanical Properties in Cementitious Materials

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was...