ارزیابی مقایسه‌ای تاثیرخاکستربادی و میکروسیلیس بر روی روند رشد، مقاومت فشاری و مقاومت الکتریکی بتن‌های در معرض آب‌های ‌سولفات دار

ﺑﺘﻦ ﻣﺴﻠﺢ ﯾﮑﯽ ازﭘﺮﮐﺎرﺑﺮدﺗﺮﯾﻦ ﻣﺼﺎﻟﺢ ﺳﺎﺧﺘﻤﺎﻧﯽ درﺻﻨﻌﺖ ﺳﺎﺧﺖ وﺳﺎز اﺳﺖ. ﺣﻤﻠﻪ ﺳﻮﻟﻔﺎتﻫﺎ ﺑﻪ ﺳﺎزهﻫﺎی ﺑﺘﻨﯽ ازﻋﻮاﻣﻞ ﺗﺎﺛﯿﺮﮔﺬاردرﮐﺎﻫﺶ دوام ﺑﺘﻦ و ﺧﺮاﺑﯽ ﺳﺎزهای اﺳﺖ. درﻃﺮاﺣﯽ و ﺳﺎﺧﺖ ﺳﺎزهﻫﺎی ﺑﺘﻨﯽ، ﻋﻤﺮﺳﺮوﯾﺲ دﻫﯽ، ﺗﻮﺳﻌﻪ ﭘﺎﯾﺪار وﻣﺒﺎﺣﺚ زﯾﺴﺖ ﻣﺤﯿﻄﯽ از ﺷﺎﺧﺺﻫﺎی ﻣﻬﻤﯽ ﻫﺴﺘﻨﺪﮐﻪ ﻣﺤﻘﻘﯿﻦ ﺟﻬﺖ دﺳﺖﯾﺎﺑﯽ ﺑﻪ ﺑﺘﻨﯽ ﭘﺎﯾﺪار ﺑﺎ ﻣﻘﺎوﻣﺖ ﺑﺎﻻ، درﺻﺪد ﺑﻬﯿﻨﻪ ﺳﺎزی ﻣﺼﺎﻟﺢ ﺑﺎ ﺟﺎﯾﮕﺮﯾﻨﯽ اﻧﻮاع ﭘﻮزوﻻنﻫﺎ ﺑﻪ ﺟﺎی ﺳﯿﻤﺎن ﺷﺪهاﻧﺪ. ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﺎ اﻧﺠﺎم آزﻣﺎﯾﺸﺎﺗﯽ ﺑﻪ ارزﯾﺎﺑﯽ ﻣﻘﺎﯾﺴﻪای ﺗﺄﺛﯿﺮﺧﺎﮐﺴﺘﺮﺑﺎدی و ﻣﯿﮑﺮوﺳﯿﻠﯿﺲ ﺑﺮ روی روﻧﺪ رﺷﺪ، ﻣﻘﺎوﻣﺖ ﻓﺸﺎری و ﻣﻘﺎوﻣﺖ اﻟﮑﺘﺮﯾﮑﯽ ﺑﺘﻦﻫﺎی در ﻣﻌﺮض آبﻫﺎی ﺳﻮﻟﻔﺎت دار ﭘﺮداﺧﺘﻪ اﺳﺖ. ﻃﺮحﻫﺎی اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﻪ دو ﺑﺨﺶ ﺑﺘﻦﻫﺎی ﻣﻌﻤﻮﻟﯽ و ﺑﺘﻦﻫﺎی دارای ﻣﺎده ﭘﻮزوﻻﻧﯽ ﺗﻘﺴﯿﻢ ﺷﺪهاﻧﺪ ﮐﻪ ﻃﺮحﻫﺎی اﺧﺘﻼط ﺑﺘﻦﻫﺎ درﻣﺤﯿﻂ ﺳﻮﻟﻔﺎﺗﯽ در11 ﮔﺮوه اﺻﻠﯽ دﺳﺘﻪ ﺑﻨﺪی ﮔﺮدﯾﺪﻧﺪ. ﮔﺮوه اول ﺑﺪون ﻫﯿﭻ ﮔﻮﻧﻪ ﻣﻮاد اﻓﺰودﻧﯽ ﺟﺎﯾﮕﺰﯾﻦ ﺳﯿﻤﺎن، ﺷﺎﻣﻞ ﯾﮏ ﻃﺮح ﺑﻪ ﻋﻨﻮان ﻃﺮح ﻣﺒﻨﺎ ﺷﺪ ودر 10ﮔﺮوه ﺑﻌﺪی، ﻫﺮﮔﺮوه ﺷﺎﻣﻞ 8 ﻃﺮح ﺑﺎ ﺟﺎﯾﮕﺰﯾﻨﯽ ﭘﻮدرﻫﺎی ﻣﯿﮑﺮوﺳﯿﻠﯿﺲ و ﺧﺎﮐﺴﺘﺮﺑﺎدی ﺑﺎ درﺻﺪﻫﺎی ﻣﺘﻔﺎوت ﺑﻪ ﺟﺎی ﺳﯿﻤﺎن ﺷﺪﻧﺪ. ﺑﺎ اﯾﻦ ﺷﺮح 81 ﻃﺮح ﮐﻪ ﻫﺮ ﮐﺪام ﺷﺎﻣﻞ 4 ﻧﻤﻮﻧﻪ ﺑﺮای آزﻣﻮنﻫﺎی ﻣﻘﺎوﻣﺖ ﻓﺸﺎری در ﺳﻨﯿﻦ 28 ،14 ،7 و 42 روزه ﺑﺎ ﺟﻤﻊﮐﻞ 324 ﻃﺮح ﺳﺎﺧﺘﻪ ﺷﺪه و ﺑﺮرﺳﯽ ﺷﺪﻧﺪ. ﻧﺘﺎﯾﺞ اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن داد در ﻣﺤﯿﻂﺳﻮﻟﻔﺎﺗﯽ، ﺑﺘﻦ ﺑﺎ ﺳﻨﮕﺪاﻧﻪ اﺳﺘﺎﻧﺪاردﮐﻪ ﺑﺎﭘﻮزوﻻنﻫﺎی ﺧﺎﮐﺴﺘﺮﺑﺎدی و ﻣﯿﮑﺮوﺳﯿﻠﯿﺲ ﺗﻘﻮﯾﺖ ﺷﺪه ﺑﺎ اراﺋﻪ ﻃﺮح اﺧﺘﻼط ﺑﻬﯿﻨﻪای ﺗﻮاﻧﺴﺖ درﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺑﺘﻦ ﺑﺪون ﺗﺮﮐﯿﺐ ﺑﺎ ﻫﯿﺞ ﮔﻮﻧﻪ ﻣﺎده ﭘﻮزوﻻﻧﯽ ﻣﻘﺎوﻣﺖ ﻓﺸﺎری ﺑﺎﻻﺗﺮی داﺷﺘﻪ ﺑﺎﺷﺪ، ﺑﻪ ﮔﻮﻧﻪای ﮐﻪ ﻧﻤﻮﻧﻪﻫﺎی ﻃﺮحﻫﺎی 5 و6 ازﮔﺮوه 2 ﺗﻘﺮﯾﺒﺎ ﺑﺎ 7/2% ﮐﺎﻫﺶ ﻣﻘﺎوﻣﺖﻓﺸﺎری دارای ﺑﯿﺶﺗﺮﯾﻦ ﻣﻘﺎوﻣﺖ ﻓﺸﺎری و ﻃﺮحﻫﺎی 30 و 31 ﺗﻘﺮﯾﺒﺎ ﺑﺎ 28% ﮐﺎﻫﺶ ﻣﻘﺎوﻣﺖ ﻓﺸﺎری دارای ﮐﻢﺗﺮﯾﻦ ﻣﻘﺎوﻣﺖ ﻓﺸﺎری ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪ ﺷﺎﻫﺪ ﺷﺪﻧﺪ و ﻣﻘﺎوﻣﺖاﻟﮑﺘﺮﯾﮑﯽ ﺑﺎ ﺟﺎﯾﮕﺰﯾﻨﯽ 15% ﻣﯿﮑﺮوﺳﯿﻠﯿﺲ در ﺳﻨﯿﻦ90روزه در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺳﻨﯿﻦ 28 روزه، 1/58 ﺑﺮاﺑﺮاﻓﺰاﯾﺶ ﯾﺎﻓﺖ.

comparative evaluation of effect of fly ash and microsilica on the development of compressive strength and electrical resistance of concretes exposed to sulfate-rich waters

reinforced concrete is one of the most widely used building materials in the construction industry. the sulfate attack on concrete structures is one of the factors effectively causing the reduced durability of concrete and structural damage. in the design and construction of concrete structures, service life, sustainable development, and environmental issues are important indicators considered by researchers in optimizing materials to achieve sustainable concrete with high strength by substituting various types of pozzolans for cement. the present study aims to compare the effects of fly ash and micro-silica on the development of the compressive strength, and electrical resistance of concretes exposed to sulfate-rich waters. the plans of this study include two types of conventional concretes and concretes containing pozzolanic material. concrete mixing plans in sulfate medium were divided into 11 groups. the first group, with no additive material as a substitution for cement, included one plan (control plan), and the other 10 groups included 8 plans with the substitution of different percentages of micro-silica and fly ash powders for cement in concrete. accordingly, 81 plans, each with 4 samples (7, 14, 28, and 42-day ages), were constructed to test compressive strength (n=324 plans). the results indicate that in the sulfate medium, with an optimal mixing design, the concrete containing standard sand reinforced with fly ash and microsilica pozzolans had higher strength compared to the concrete with no pozzolan, moreover, the maximum (a 6% reduction in strength) and minimum (a 28% reduction in strength) durability was obtained for samples # 5 and 6 of group 2 and samples #30 and 31, respectively. also, with the substitution of 15% microsilica, a 1.58-fold increase in the electrical resistance was observed in the 90 day-old concrete sample compared to the 28 day-old sample