Utilization of air-cooled blast furnace slag as a 100 % replacement of river sand in mortar and concrete
- Vol.96(7), Jul
- Mumbai ACC LTD 2022
- 6-21p.
The steel industries generate millions of tons of slag as byproduct during their production stages. This slag is classified according to its origin and form of cooling conditions. The slag that is slowly cooled is called air-cooled blast furnace slag (ACBFS). Crystalline nature is observed in ACBFS slag because of slow cooling by air. As per IS: 383 (2016), a maximum of 50 % replacement of natural sand with iron slag sand is allowed in plain concrete. The aim of this study is to evaluate the feasibility of using ACBFS as a replacement of river sand in mortar and plain concrete at replacement levels of 0 %, 25 %, 50 %, 75 %, and 100 % by weight. The effect of ACBFS replacement levels of river sand on workability, pull-off strength, and compressive strength of mortar system is studied. Further, the effect of ACBFS replacement levels on fresh, mechanical and durability properties of concrete is studied. Compressive strength, elastic modulus, and split tensile strength of concrete at different replacement levels is evaluated. A detailed study on durability properties such as water sorptivity, water absorption, porosity, and total charge passed in rapid chloride permeability (RCPT) is conducted. The replacement of river sand with ACBFS sand has shown no detrimental effect on the properties studied for both mortar and concrete. The concrete with increasing replacement levels of ACBFS sand showed reduction in porosity and absorption, although, the ACBFS sand has higher water absorption. The ACBFS can be considered as a suitable substitute for river sand for even 100 % replacement.