Microstructural and rate of water absorption study on fly-ash incorporated cement mortar

Today durability is the most concerning factor in the construction field. Durability and strength are mainly controlled by microstructure of the concrete. Dense microstructure with less interconnected pores results in good strength and durable concrete. A dense microstructure can be obtained by providing good compaction, curing and by the use of mineral admixtures. This paper deals with the study on the effect of fly ash addition and superplasticizer dosage and its family in improving the strength, microstructure and durability of mortar. For this purpose mortar is prepared at a water to cement ratio of 0.37 with ordinary portland cement, class F fly ash at different percentage replacement to cement such as 0%, 15%, 25%, and 35% and superplasticizer. The superplasticzer from four different family such as Polycarboxylate ether (PCE), Lignosulphonate (LS), Sulphonated Naphthalene Formaldehyde (SNF) and Sulphonated Melamine Formaldehyde (SMF) is also used in this study. Durability of the mortar is determined by checking the 28th day rate of water absorption in mortar specimen and also by checking the size and connectivity of the pores by means of microscopic study in hardened concrete. There is decrease in 28th day compressive strength for mortar specimen with all levels of fly-ash replacement was observed in this study. Improvement in the compressive strength of the mortar compared to control specimen were observed with the addition of superplasticizer in all levels of addition of fly-ash. A good correlation between the pore size and compressive strength were also observed in this study. (C) 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Materials and Manufacturing Applications [IConAMMA 2017].