ﻣﺮوري ﺑﺮ ﻋﻮاﻣﻞ ﻣﻮﺛﺮ ﺑﺮ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦ ﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ

An Overview of the Factors Affecting the Mechanical Properties of Recycled Concrete

ﯾﮑﯽ از ﻣﻌﻀﻼت ﮐﻨﻮﻧﯽ ﺟﻮاﻣﻊ، ﻧﺤﻮه روﯾﺎروﯾﯽ ﺑﺎ ﻣﺼﺎﻟﺢ ﺣﺎﺻﻞ از ﺗﺨﺮﯾﺐ ﺳﺎﺧﺘﻤﺎنﻫﺎ و اﺛﺮات زﯾﺴﺖﻣﺤﯿﻄﯽ اﻧﺒﺎﺷﺖ آنﻫﺎ ﻣﯽﺑﺎﺷﺪ. ﺑﺘﻦ ﺑﻪ ﻋﻨﻮان ﯾﮑﯽ از اﺻﻠﯽﺗﺮﯾﻦ اﺟﺰاي ﺻﻨﻌﺖ ﺳﺎﺧﺖ از آﻏﺎز ﻓﺮآﯾﻨﺪ ﺗﻮﻟﯿﺪ، اﺟﺮاء و ﺗﺨﺮﯾﺐ، ﻧﻘﺶ زﯾﺎدي در اﯾﺠﺎد آﻟﻮدﮔﯽﻫﺎي زﯾﺴﺖﻣﺤﯿﻄﯽ دارد. از آﻧﺠﺎﯾﯽﮐﻪ ﺑﯿﺶ از %70 از ﺑﺪﻧﻪ اﺻﻠﯽ ﺑﺘﻦ را ﺳﻨﮕﺪاﻧﻪﻫﺎ ﺗﺸﮑﯿﻞ ﻣﯽدﻫﻨﺪ، ﺗﺮوﯾﺞ ﻓﺮﻫﻨﮓ و ﻣﻼﺣﻈﺎت ﻣﺒﺘﻨﯽ ﺑﺮ رﻋﺎﯾﺖ اﺻﻮل ﺗﻮﺳﻌﻪ ﭘﺎﯾﺪار در ﻓﺮآﯾﻨﺪ ﻃﺮاﺣﯽ، ﺳﺎﺧﺖ و ﺗﺨﺮﯾﺐ ﺑﺘﻦ از اﻫﻤﯿﺖ ﺑﺎﻻﯾﯽ ﺑﺮﺧﻮردار اﺳﺖ. ﯾﮑﯽ از اﺻﻮل اﺳﺎﺳﯽ ﺗﻮﺳﻌﻪ ﭘﺎﯾﺪار، ﺗﻮﺟﻪ ﺑﻪ اﻫﻤﯿﺖ ﺑﺎزﯾﺎﻓﺖ اﺳﺖ. ﺑﺎزﯾﺎﻓﺖ ﺑﺘﻦﻫﺎي ﺣﺎﺻﻞ از ﺗﺨﺮﯾﺐ در ﻗﺮن اﺧﯿﺮ ﺑﻪ ﯾﮑﯽ از ﻋﻼﯾﻖ ﻣﻬﻢ ﭘﮋوﻫﺶﮔﺮان ﻋﺮﺻﻪ ﺑﺘﻦ ﺗﺒﺪﯾﻞ ﺷﺪه اﺳﺖ، ﺑﻪ ﻧﺤﻮي ﮐﻪ ﭘﺲ از ﺑﺮرﺳﯽ و ﺷﻨﺎﺧﺖ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ و دوام آنﻫﺎ، اﻣﺮوزه در ﮐﺸﻮرﻫﺎي ﺗﻮﺳﻌﻪ ﯾﺎﻓﺘﻪ ﻣﻨﺎﺳﺒﺎت ﻻزم ﺟﻬﺖ ﺷﻨﺎﺧﺖ ﻋﻤﻠﮑﺮد ﺳﺎزهاي اﯾﻦ ﺑﺘﻦﻫﺎ در ﺣﺎل ﭘﺎﯾﻪرﯾﺰي اﺳﺖ. ﻫﺪف اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺮرﺳﯽ ﻧﺘﺎﯾﺞ ﭘﮋوﻫﺶﻫﺎي اﻧﺠﺎمﺷﺪه در ﮐﺸﻮرﻫﺎي ﻣﺨﺘﻠﻒ در ﻋﺮﺻﻪ ﺷﻨﺎﺧﺖ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ اﺳﺖ. در اﯾﻦ راﺳﺘﺎ ﺑﯿﺶ از 80 ﻣﻘﺎﻟﻪ ﭘﺮاﺳﺘﻨﺎد ﭼﺎپﺷﺪه در ﻣﺠﻼت ﻣﻌﺘﺒﺮ ﻓﻨﯽ ﺑﺮرﺳﯽ ﺷﺪه و ﻋﻮاﻣﻞ ﻣﺸﺘﺮﮐﯽ را ﮐﻪ ﻣﺤﻘﻘﺎن در ﺗﺤﻠﯿﻞ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ ﺑﯿﺸﺘﺮ ﻣﻮرد ﺗﻮﺟﻪ ﻗﺮار دادهاﻧﺪ، در ﺷﺶ ﮔﺮوه دﺳﺘﻪﺑﻨﺪي ﺷﺪﻧﺪ. ﺗﺎﺛﯿﺮ ﻫﺮ ﯾﮏ از اﯾﻦ ﮔﺮوهﻫﺎ ﺑﺮ ﻣﻘﺎوﻣﺖ ﻓﺸﺎري، ﻣﻘﺎوﻣﺖ ﮐﺸﺸﯽ و ﺿﺮﯾﺐ ارﺗﺠﺎﻋﯽ ﺑﺘﻦ ﺑﺮرﺳﯽ ﮔﺮدﯾﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻧﻮع، اﻧﺪازه و ﮐﯿﻔﯿﺖ ﺳﻨﮕﺪاﻧﻪﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ در ﺗﻌﯿﯿﻦ ﺳﻄﺢ ﺟﺎﯾﮕﺰﯾﻨﯽ ﻣﺼﺎﻟﺢ ﺑﺎزﯾﺎﻓﺘﯽ در ﺑﺘﻦ ﺑﺴﯿﺎر ﻣﻮﺛﺮﻧﺪ. ﺷﺮاﯾﻂ ﻋﻤﻞآوري، ﻣﻮاد ﮐﺎﻫﻨﺪه آب و ﻣﻮاد ﭘﻮزوﻻﻧﯽ ﮔﺮﭼﻪ در ﺑﻬﺒﻮد ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ ﻣﻮﺛﺮﻧﺪ،اﻣﺎ ﻧﻤﯽﺗﻮاﻧﻨﺪ از ﺗﺎﺛﯿﺮ ﻧﺎﻣﻄﻠﻮب اﻓﺰاﯾﺶ ﺟﺎﯾﮕﺰﯾﻨﯽ ﻣﺼﺎﻟﺢ ﺑﺎزﯾﺎﻓﺘﯽ ﺑﺮ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦ ﺑﮑﺎﻫﻨﺪ.در زﻣﯿﻨﻪ ﺗﺄﺛﯿﺮ ﺳﻦ ﺑﺮ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺑﺘﻦﻫﺎي ﺑﺎزﯾﺎﻓﺘﯽ، اﺟﻤﺎع ﻧﻈﺮ اﯾﻦ اﺳﺖ ﮐﻪ ﺑﺮﺧﯽ از اﯾﻦ ﺧﻮاص ﻫﻤﺎﻧﻨﺪ ﺑﺘﻦﻫﺎي ﻣﻌﻤﻮﻟﯽ اﺳﺖ.

Concrete, as one of the main components of the manufacturing industry since the beginning of the process of production, operation and destruction, plays a major role in the creation of environmental pollution. Since more than 70% of the main body of concrete is aggregate, the promotion of culture and considerations based on the principles of sustainable development in design, construction and demolition process of concrete is of great importance. One of the basic principles of sustainable development is the importance of recycling. Recycling of damaged concrete in the last century has become one of the most important interests of researchers. So, after studying and recognizing their durability and mechanical properties (MP’s), today in developed countries, the necessary relationships for the recognition of structural performance of these concretes is under construction. The purpose of this research is to investigate the results of research carried out in different countries in the field of recognition of the MP’s of recycled concretes (RC’s). More than 80 articles published in prestigious technical journals were examined and classified together in the six groups that the researchers considered in analyzing the MP’s of RC’s. The effect of each of these groups on compressive and tensile strengths and elasticity of concrete were studied. The results showed that the type, size and quality of recycled aggregates (RA’s) are very effective in determining the level of replacement of recycled materials (RM’s) in concrete. Curing conditions, water reducing and pozzolanic materials, although effective in improving the MP’s of RC’s, cannot reduce the adverse effects of increasing the replacement of RM’s on the mechanical properties of concrete. Concerning the effect of age on the mechanical properties of RC’s, it is common ground that some of these properties are similar to conventional ones.