Investigating the performance and durability of high mechanical milling nano pulverised refused SCMs

This study investigated the performance and durability of high-mechanical-milling nano-pulverized industrial reject supplementary cementitious materials (SCMs). The research utilized industrial reject (IR-1), specifically Ground Blast Furnace Slag (GBFS), as the SCM. As-received IR-1 GBFS was milled for 90 minutes to achieve nano-sized particles, and its properties were compared with the un-milled, or before-milled (BM) material. Three pozzolanicity tests were conducted to compare the before milled (BM) and after-milled (AM) materials. Additionally, M30 grade concrete mixes were developed with cement partially replaced by 30%, 35%, and 40% using both BM and AM IR-1 materials. Mechanical performance, including compressive strength, flexural strength, and split tensile strength, along with durability tests such as water absorption, sorptivity, and rapid chloride penetration, were conducted for the BM and AM IR-1 blended concretes. The results showed that AM IR-1 blended concrete achieved the required design strength at a 30% cement replacement level. Furthermore, the AM IR-1 blended concrete exhibited 40% higher compressive strength, 39% higher flexural strength, and 29% higher split tensile strength compared to the control concrete. Durability testing also revealed significant improvements in AM IR-1 blended concrete, with reductions of 19.65% in water absorption, 24.71% in sorptivity, and 38% in chloride penetration. This study demonstrates that industrial waste, such as GBFS, can be effectively utilized as a sustainable alternative to traditional materials in the construction industry. Additionally, nano-pulverization treatment significantly enhances the pozzolanicity and overall performance of materials that may not meet the physicochemical standards specified in IS 3812-(Part 1):2017 and ASTM C618-19.