مطالعه ‌تجربي استفاده از آهك ميكرونيزه كارخانه فولاد مباركه در توليد بتن خودتراكم

Abstract With the expansion of industrial activities, the management of industrial waste has become a critical environmental an‎d economic issue. Large steel industries, including Mobarakeh Steel Company, produce significant amounts of powder waste annually, which, due to the lack of suitable utilization methods, often creates environmental challenges an‎d storage costs. Micronized lime powder is one of these industrial wastes that, given its physical an‎d chemical properties, has the potential to be used in construction materials, particularly in the production of various types of concrete. Utilizing such wastes in concrete production can not only reduce the consumption of primary raw materials but also contribute effectively to sustainable development an‎d improved industrial waste management. The present study aimed to experimentally investigate the effect of replacing a portion of cement with micronized lime powder from Mobarakeh Steel Company on the rheological behavior an‎d mechanical properties of self-compacting concrete (SCC). Initially, a reference SCC mixture was prepared in accordance with Iranian national codes, European stan‎dards, an‎d internationally recognized guidelines. The rheological an‎d mechanical properties of this reference concrete—including compressive, flexural, an‎d tensile strengths, as well as stan‎dard workability an‎d flow tests such as slump flow, J-Ring, L-Box, V-Funnel, an‎d U-Box—were determined to characterize the baseline performance. Subsequently, to eva‎luate the effects of replacing cement with micronized lime powder at 5%, 10%, an‎d 15% by weight, a Taguchi experimental design using an L9 array was employed. Four key factors, including the powder-to-water ratio (0.40, 0.43, an‎d 0.45), superplasticizer dosage (2.2, 2.4, an‎d 2.6 kg/m³), microsilica content (16, 18, an‎d 20 kg/m³), an‎d the replacement percentage of micronized lime powder (5%, 10%, an‎d 15%), were studied at three levels. Based on this design, nine different concrete mixtures were prepared, an‎d all rheological an‎d mechanical tests applied to the reference mixture were repeated on these experimental mixes. Statistical analysis an‎d combined optimization using Taguchi methods in Minitab software indicated that the optimal mixture consists of 66 kg/m³ of micronized lime powder, 16 kg/m³ of microsilica, 2.2 kg/m³ of superplasticizer, an‎d a powder-to-water ratio of 0.43. The optimal mixture also included 1348 kg/m³ of san‎d an‎d 298 kg/m³ of coarse aggregate. This optimized mixture maintained mechanical strengths within the acceptable range for SCC, enhanced workability, improved flowability, an‎d reduced cement consumption. Overall, the results of this study demonstrate that the optimal use of micronized lime powder can serve as an effective approach to producing sustainable self-compacting concrete with adequate technical performance an‎d significant environmental benefits.

5

ماريانا‌‌‌‌‌ آيدا آبكدير

158786