Critical Review: Freeze-Thaw Durability of Activated Blast-Furnace Slag Cement Concrete

Critical Review: Freeze-Thaw Durability of Activated Blast-Furnace Slag Cement Concrete

Introduction

This research paper provides the critique of the article analyzing the freeze thaw durability of activated blast furnace slag cement concrete (ABFSC) and the associated air-void parameters. Cement forms a primary part of concrete and concrete is a primary foundational material in any civil and constructional industry. With the technological advancement in the field of construction, the modern structures demand more durability, strength, resistance to chemical attacks at lower costs. The area of study of the alkali activated waste materials has become a primary research area of constructional technology because of its importance and usage in the synthesizing of inexpensive constructional material which are ecologically sound as well.

This paper analyzes the properties of ABFSC against the properties of ordinary Portland cement (OPC) on the basis of the chemical composition, mix proportions and testing of freeze-thaw durability of both moist cured and heat cured OPC and ABFSC concretes at different air content levels.

Discussion

Replacement of Portland cement

The need of new binder as a replacement of OPC for the enhanced durability and environmental performance and the reduction of Carbon dioxide emissions originated primarily because the OPC structures built in the past decades are going through serious disintegration issues which points out to the handicaps of OPC binders. The case of a tunnel in Dubai and the pile foundation case were mentioned by Mehta (1991) as the OPC structures facing disintegration. Also, Gjorv mentioned the figure of 40 percent of the total bridges of the United States facing the disintegration due to freeze-thaw effect and corrosion. Apart from the durability and environmental problems, imperfect placement of concrete, curing operations involved, and intrinsic properties of Portland cement also contributed to the search of an effective alternative binder for the replacement of Portland cement. OPC being a pre-eminent constructional material but its low durability when exposed to severe environment, the environmental threats posed and the emission of CO2 has always been a significant issue. The consumption of OPC has been reduced by civil engineers and the constructional technology is shifting to the usage of mineral admixtures.

Alkali Activated Blast Furnace Slag Cement (ABFSC)

In the Blast furnace during the manufacturing of pig iron, the blast furnace slag is obtained as a byproduct with the flux of limestone as primary constituent which is due to the involvement of calcium carbonate in the calcination operation. The alkali activated BFS acts not only as a partial replacement of the cement but as a sole binder in concrete production. By the use of alkaline activator, the BFS slag can achieve high compression strength as it is low performance cementitious material in nature.

With the increasing use of Alkali Activated Blast Furnace Slag Cement concrete in the civil industry, a significant dropdown in the use of Ordinary Portland Cement has been observed. ABSC apart from conserving significant amount of energy also pose no environmental threats. However, the technology being relatively immature compared to OPC technology, ...