Effect of curing on alkalinity and strength of cement-mortar incorporating palm oil fuel ash

Payam Shafigh , Sumra Yousuf , Belal Alsubari , Zainah Ibrahim

Abstract

Palm oil fuel ash (POFA) is a newly emerging pozzolanic material having high amount of silica content. Various forms of POFA were used in cement-based materials (CBMs) in replacement of cement in different dosages of low and high volume. Although, there are many researches on POFA to be used in concrete and mortar, however, this material was not practically used in the construction industry. Engineers and designers need to be confident to use any new developed materials by knowing all engineering properties at short and long terms. As durability concern, concrete pH value is one of the most important properties. Portland cement produces are alkaline initially, however, it may be reduced due to aging and its components. It is believed that by incorporation of supplementary cementitious materials in CBMs the pH value reduces due to utilization of Ca(OH)2 in pozzolanic reaction. This study is the first attempts to understand the pH value of mortars containing up to 30% POFA under different curing conditions and its changes with time. The results were also compared with the pH of ground granulated ballast furnace slag (GGBFS) and fly ash (FA) content mortars. In addition, the compressive strength of different mortars under different curing conditions were also studied. The results showed that the pH value of control mix (without cementitious materials) was more than all the blended cement mortars indifferent curing conditions at the same ages. However, there was a reducing trend in the pH value of all mortar mixes containing POFA.

Key Words

cementitious materials; compressive strength; curing; durability; palm oil fuel ash; pH value

Address

(1) Payam Shafigh — Center for Building, Construction & Tropical Architecture (BuCTA), Faculty of Built Environment, University of Malaya, 50603 Kuala Lumpur, Malaysia
(2) Sumra Yousuf — Department of Building and Architectural Engineering, Faculty of Engineering & Technology, Bahauddin Zakariya University Multan 60000, Pakistan
(3) Belal Alsubari — Department of Civil Engineering, Faculty of Engineering, Miami College of Henan University, Kaifeng, Henan, China
(4) Zainah Ibrahim — Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.

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