Geotechnical properties of steel slag aggregates: Shear strength and stiffness

Steel slag is an industrial by-product formed in the furnace during the steelmaking process. Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are the primary by-products of steelmaking from steel scraps. This research evaluates the physical, geotechnical and engineering properties of LFS, EAFS and a blend comprising 50% LFS and 50% EAFS (LFS50 + EAFS50) through laboratory testing. The specialized laboratory tests undertaken in this study include California bearing ratio (CBR) and unconfined compressive strength (UCS) tests, direct shear tests (DSTs), consolidated drained (CD) triaxial tests and repeated load triaxial (RLT) tests. The shear strength responses of the steel slag were found to vary with the dilatancy-induced peak strength of the LFS and the LFS50 + EAFS50 mixture and the dilatancy-associated strain-hardening behavior of the EAFS. Based on the high shear strength parameters and the adequate stiffness that were attained, the steel slag was found to have the potential for usage as a geo-material. LFS and LFS50 + EAFS50 were well-graded and had high CBR values, which would deem them suitable for roadwork applications. EAFS, however, was found to be poorly graded and to have relatively lower CBR values, which would deem it suitable for less stringent applications such as engineering fill and pipe bedding. The viability of using these by-products as geo-materials in civil infrastructures can transform these current waste by-products, particularly LFS, from being stockpiled at steel company plants to being used as alternative green material

A novel green construction material from water treatment sludge

A novel water treatment sludge-fly ash geopolymer is investigated in this research with the intention to develop an alternative green construction and building materials, without the usage of Portland cement as a cementing agent. Two waste by-products namely water treatment sludge and fly ash (FA) were used in this research. The liquid alkaline activator, L used was a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). This paper investigates the effect of liquid alkaline content and Na2SiO3/NaOH ratio on compressive strength of sludgefly ash geopolymer. The scanning electron microscopy (SEM) is undertaken to understand the role of of liquid alkaline content and Na2SiO3/NaOH ratio on strength development. Test results show that Na2SiO3/NaOH ratio of 80:20 and L/FA ratio of 1.3 are the optimum ingredient providing maximum unit weight and strength. The water treatment sludge traditionally destined for landfill can be used in a sustainable manner as alternative aggregate to develop geopolymer masonry unit

Numerical study on laterial movement pattern of bearing reinforcement earth (BRE) wall

Abstract not available