Synergism between palm oil fuel ash and slag: Production of environmental-friendly alkali activated mortars with enhanced properties by Huseien, Ghasan Fahim, Ismail, Mohammad, Md. Tahir, Mahmood, Mirza, Jahangir, A. Khalid, Nur Hafizah, Asaad, Mohammad Ali, Husein, Ahmed Abdulameer, Sarbini, Noor Nabilah