Issue 66

S.E. Daguiani et alii, Frattura ed Integrità Strutturale, 66 (2023) 88-111; DOI: 10.3221/IGF-ESIS.66.05

replacement ratios and qualities comparable to, or even superior to, traditional cement systems. K EYWORDS . Mineral additions, Mixture design approach, Ternary binder, Fresh properties, Microstructure, Strength-activity index.

I NTRODUCTION

T

he world produces a significant quantity of construction materials annually, and this production has increased due to rapid urbanisation and the expanding global population. Cement, since its invention, has been recognised as the most commonly used binding agent in construction materials. Its utilisation has enabled the construction of extensive infrastructure that exhibits high levels of strength and durability at a relatively affordable cost. In Algeria, the annual cement production reaches 18 million tonnes, with a market demand that exceeds this quantity by approximately 5 million tons. This highlights the need to bridge the gap in order to meet the growing market requirements [1]. Cement production is predicted to expand by up to 4 billion tonnes annually by 2030 [2]. Furthermore, its production contributes to nearly 5 to 7 % of carbon dioxide (CO 2 ) emissions, total global gas emissions [3]. Due to the development of the sector of cement as well as the demand for bolder and slender constructions, ordinary concrete no longer meets the requirements for the execution of these works. In this context, other cementitious mixtures and concretes with properties superior to ordinary concrete evolved to fulfil this need. This is the case for self-compacting, geopolymer, high-performance, high strength, and, more newly, ultra-high-performance concrete. Supplementary cementitious materials (SCMs) from industrial wastes or natural resources are considered sustainable solutions that can be replaced partially with cement for producing these concretes to achieve better engineering properties and improve performance of these concretes. Several industrial wastes have been successfully used as SCMs, including fly ash, waste glass, marble waste, cement kiln dust, and granulated blast furnace slag [4–7]. Partially replacing cement with these waste materials has both ecological and economic impacts, offering a sustainable and environmentally friendly solution that conserves natural resources [8]. Among these added wastes, granulated blast furnace slag (GBS) is a by-product generated from the production of iron and steel, which is removed from the blast furnace in steam or water, dried, transformed into granules, and processed into a powder in a ball mill. GBS is finely ground to produce a product known as ground granulated blast furnace slag (GGBS) [9]. GGBS was used as a cement replacement in the production of concrete from a low amount (10 % - 30 %) [10] to a high amount (50 % - 80 %) [4][11]. Crossin, E. [12] has demonstrated that using GGBS as a cement replacement reduced greenhouse gas emissions. According to prior studies, increasing GGBS content in the binder causes lower heat of hydration [13–15]. At high-level replacement of GGBS in binders, the setting time can be slightly extended due to its latent hydraulic properties. Hooton [16] found that the setting time of the GGBS mix can be extended in the range of 60-120 min with low ambient temperature and high replacement levels. The finishing time can only increase by a few minutes in hot weather with temperatures over (20 °C). It makes concrete more workable for extended periods, resulting in fewer joints. Additionally, it is beneficial when applied in warm weather. Other studies [13][17] have shown that mortars with 50 % of slag as a cement substitute are more workable. Rahman et al. reported that using GGBS has no adverse effect on the expansion due to the less free lime available in the mixtures that incorporate GGBS as a cement substitute [18]. Another waste product that is produced in significant amounts and is challenging to get rid of is waste glass (WG). It is well known that WG generates several environmental problems due to its non-biodegradable characteristics. In Algeria, about 170,000 tonnes of glass are discarded annually, even though it takes at least 4000 years to disintegrate [19]. It is called waste glass powder (WGP) when waste glass is finely ground into powder. This waste product is classified as a pozzolanic material since it contains amorphous structures and a significant quantity of calcium and silicon. According to ASTM C 618-12a, it satisfies all of the requirements for pozzolanic materials [20]. Thus, waste glass can be used to replace cement partially. Aliabdo et al. [21] reported that using WGP as cement substituting decreases the water demand. In contrast, when the replacement level of WGP increases, the value of water requirement percentage decreases linearly. In previous studies, it was found that increasing quantities of WGP extended the initial and final setting times of the cement paste [21–23], resulting in better workability [24] as well as higher resistance to chloride penetration of mortar [25]. A synergistic effect may be created by combining different SCMs, which contributes to improved mechanical properties or durability of concrete compared to using it alone [26–28]. Several authors have performed the optimisation of ternary or quaternary cement constituent proportions [26][29–32]. Hence, a few research have been published on optimising the

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