Yes it can be added during transportation by automobile concrete mixture, provided there is enough time for the whole fibers to distribute through the concrete mass.
I am an author from Hunan University. I am sharing my last book with you. Please share it with your students.
Title is “Evolution of Automobile Design, A Brief Introduction” Jaafarnia, Mohsen (2019). Evolution of Automobile Design, A Brief Introduction. Ghochan, Iran: Yadegar Omr Publication. ISBN: 978-600-91409-8-5