Effect of Concrete Mixing Methods on Statistical Parameters of Recycled Aggregate Concrete


Dilbas H.

3RD INTERNATIONAL ISTANBUL SCIENTIFIC RESEARCH CONGRESS (ICONSOS), İstanbul, Türkiye, 8 - 10 Ocak 2021

  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye

Özet

Factors such as urban renewal processes, natural disasters, change in consumptions causes demolition of structures in cities and re-construction of demolished structures. Thus, construction and demolition waste (CDW) trouble has been occurred in the cities. Despite reuse of waste and no brutal release of waste into nature as a result of environmental approaches, it is seen that there are many steps and researches that need to be done in this field for CDW and also many problems await solutions [1]. To enlighten the solution of CDW, CDW is considered as a material for concrete, i.e., recycled aggregate (RA). Hence, the effect of concrete mixing techniques has been investigated in this study using RA in the mixes. The Absolute Volume Method (AVM) [2] specified in TS 802 (2016) developed by the Turkish Standards Institute and the Equivalent Mortar Volume Method (EMV) [3] proposed in the literature have been taken into account in the design of concretes. The gradation of aggregate in the mixes are constant. Natural aggregate concrete (NAC) designed according to AVM is considered as control one. Recycled aggregate concrete designed according to AVM (RAC1) and EVM (RAC2) include 4-22.4 mm RA replacing 4-22.4 mm natural aggregate (NA) in concrete with constant gradation. As a result, three concrete series such as NAC, RAC1 and RAC2 are designed and C30/37 strength class is selected for all. Each concrete series include thirty cubic specimens with the dimension of 15x15x15 cm and concretes are produced in the laboratory. Then, the specimens are cured in 22±2oC water for 28 days and compressive strength tests are conducted at the age of 28 days on the specimens. Strength class of concretes and statistical parameters of compressive strength data for each series are examined. According to the pure compressive strength test results, NAC has C30/37 strength class. However, it is determined that RAC1 is not in C30/37 strength class and has C25/30 strength class. Besides, RAC2 is in C35/45 strength class. In addition, it is found that standard deviation (SD) is affected by RA and mixing procedures such as AVM and EVM and the maximum SD is observed for RAC2. It is suggested to be appropriate to analyze the results with advanced statistical methods.

Factors such as urban renewal processes, natural disasters, change in consumptions causes demolition of structures in cities and re-construction of demolished structures. Thus, construction and demolition waste (CDW) trouble has been occurred in the cities. Despite reuse of waste and no brutal release of waste into nature as a result of environmental approaches, it is seen that there are many steps and researches that need to be done in this field for CDW and also many problems await solutions [1]. To enlighten the solution of CDW, CDW is considered as a material for concrete, i.e., recycled aggregate (RA). Hence, the effect of concrete mixing techniques has been investigated in this study using RA in the mixes. The Absolute Volume Method (AVM) [2] specified in TS 802 (2016) developed by the Turkish Standards Institute and the Equivalent Mortar Volume Method (EMV) [3] proposed in the literature have been taken into account in the design of concretes. The gradation of aggregate in the mixes are constant. Natural aggregate concrete (NAC) designed according to AVM is considered as control one. Recycled aggregate concrete designed according to AVM (RAC1) and EVM (RAC2) include 4-22.4 mm RA replacing 4-22.4 mm natural aggregate (NA) in concrete with constant gradation. As a result, three concrete series such as NAC, RAC1 and RAC2 are designed and C30/37 strength class is selected for all. Each concrete series include thirty cubic specimens with the dimension of 15x15x15 cm and concretes are produced in the laboratory. Then, the specimens are cured in 22±2oC water for 28 days and compressive strength tests are conducted at the age of 28 days on the specimens. Strength class of concretes and statistical parameters of compressive strength data for each series are examined. According to the pure compressive strength test results, NAC has C30/37 strength class. However, it is determined that RAC1 is not in C30/37 strength class and has C25/30 strength class. Besides, RAC2 is in C35/45 strength class. In addition, it is found that standard deviation (SD) is affected by RA and mixing procedures such as AVM and EVM and the maximum SD is observed for RAC2. It is suggested to be appropriate to analyze the results with advanced statistical methods.