The construction industry is an enormous economic sector with a profound economic, social, and environmental impact. The building sector is responsible for one-third of total energy consumption and, notably, construction activities account for 39% of the total carbon emissions in the world. Therefore, nowadays, the promotion of green building concepts is essential for all countries. Typically, the sustainability level of a building is evaluated by specified certification systems through rating assessment tools. The development of national assessment tools is necessary for the developing world due to environmental, social, and economic issues; consequently, a national assessment tool adopted under specific local conditions would provide a more precise assessment. This paper analyzes the rating system of BREEAM, LEED, CASBEE, and Green Globes certification systems and discusses their adoption with assessment measures for the existing buildings in Kazakhstan’s reality. The following main criteria were discussed during six roundtable sessions: sustainable site and landscape, energy and carbon footprint reduction, water and wastewater management, indoor environmental quality, sustainable building materials, commissioning, and maintenance. A set of assessment criteria and measures were suggested, and 43 existing buildings were assessed. Only eight buildings reached a high rating level. The “sustainable site and landscape” and “indoor environmental air quality” categories were the categories with the highest scores; otherwise, “energy and carbon footprint reduction” with “water and wastewater management” had the lowest average scores. One of the buildings was evaluated separately by several experts to check the consistency of the suggested assessment measures. This evaluation also provided insight into how the assessors’ knowledge and experience may change the overall rating scores obtained. The most critical issues for the existing buildings in Kazakhstan’s reality were discussed. Despite the widespread adoption of green certification methodology, the application of global certification systems in Kazakhstan remains complicated due to the lack of knowledge and limited awareness.

Basic oxygen furnace slag (BOFS) is a waste product generated during steel production. The utilization of BOFS in construction applications is considerably limited because of its inherent characteristics leading to volumetric expansion behavior caused by the chemical reaction between free lime (f-CaO) and water. The main objective of this paper is to investigate the material properties of normal mortar and geopolymer mixtures that contain BOFS aggregates. Three different aggregates were used to compare their performance, including siliceous river sand, fresh BOFS aggregate (within 1-month age), and stockpiled (more than 5-year age) BOFS aggregate. Test methods included a compressive strength test, accelerated mortar bar expansion test, and thermal conductivity test. Test results revealed that (1) geopolymer mixtures containing BOFS aggregate had comparable compressive strength with mortar mixture with river sand, (2) geopolymer mixtures have very low volume expansion, (3) thermal conductivity of geopolymer mixtures having both river sand and BOFS was lower than normal cement mortar mixture containing river sand. Therefore, geopolymer technology seems a key solution for converting BOFS slag into valuable construction materials. Therefore, a geopolymer mixture containing BOFS aggregate can be used as an energy-saving material.

As one of the by-products in the steel industry, granulated blast furnace slag (GBFS) is widely used as an aggregate or a pozzolanic material (a partial replacement for Portland cement) in the concrete mixture after the crushing or grinding process. However, using a basic oxygen furnace slag (BOFS) as a cementitious material is limited because of its inherent shortcomings such as low cementing property and undesirable expansion characteristics due to free lime. To overcome BOFS’s these properties, the BOFS was ground, blended with the ground granulated blast furnace slag (GGBFS), and used as a pozzolanic material in this research. A total of five mortar mixtures were developed, including ordinary Portland cement (OPC) as a control group, two binary mixtures, and two ternary blended mixtures with 50% cement replacements by GGBFS and BOFS by weight percentages. Properties of these mixtures were evaluated according to ASTM C 989 and C 311 standard specifications that include compressive strength, alkali-silica reaction (ASR), and sulfate resistance tests. Moreover, basic material characterization of GGBFS and BOFSs was investigated by X-ray diffraction (XRD), chemical composition analysis (XRF), and particle size distribution (PSD). The test result shows that the blended mixture with 15% BOFS and 35% GGBFS satisfied the strength activity index and good ASR and sulfate resistance.

During the steelmaking process, many by-products, such as blast-furnace slag (BFS), basic oxygen furnace slag (BOFS), and ladle slag (LS), are generated. Unlike BFS, utilizing BOFS is limited due to its expansive volumetric characteristics by the transformation process of free lime (f-CaO) and free magnesia (f-MgO) to portlandite (Ca(OH)2) and brucite (Mg(OH)2). The natural aging process may help BOFS used as an aggregate in mortar or concrete because harmful elements such as f-CaO and f-MgO could be consumed during this stage. This study evaluated compressive strength and expansion characteristics of mortar mixtures incorporating chronologically aged-BOFS aggregates blended with ground granulated blast furnace slag (GGBFS) and ASTM class F fly ash (FFA). Test results revealed that the longer aged BOFS aggregate, the lower compressive strength, regardless of mixture types. The aging process of BOFS aggregate reduced the expansion of mortar mixtures. Incorporating GGBFS or FFA into mortar mixtures containing BOFS aggregate even more reduced the expansion of the mixture.