Physico-mechanical properties of polymer concrete containing micro-filler of palm oil fuel ash by A. Khalid, Nur Hafizah, Ismail, Mohammad, Mohd. Sam, Abd Rahman, Mohamed, Azman, A. Ismail, Mohamed, Jamellodin, Zalipah, Salleh, Norhafizah, A. Hamid, Noor Azlina, A. Majid, Masni