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Experimental Study on the Water Content Formula of Fresh Concrete by Microwave Oven Drying Test Method

고주파 가열건조 시험방법에 의한 굳지 않은 콘크리트의 단위수량 추정식에 관한 실험적 연구

  • Received : 2022.12.14
  • Accepted : 2023.02.02
  • Published : 2023.04.20

Abstract

In this research, the microwave oven drying method was investigated as a potential accurate testing approach for determining the water content of fresh concrete. To do so, water content estimation formulas employed in three prominent oven drying test methods were selected, and the calculation principles for each equation, along with potential error factors arising during the actual testing process, were considered. Moreover, a concrete test was conducted to validate the possible error factors. Consequently, it was confirmed that estimation errors in the water content of fresh concrete can occur due to sample deviations arising during the wet screening process for creating mortar specimens or deviations in the coarse aggregate sampling quantity during the sample collection process.

본 연구에서는 굳지 않은 콘크리트의 단위수량 정밀 측정방법으로써 고주파가열법을 검토하기 위해 3가지의 대표적인 가열건조 시험방법에 사용되는 단위수량 추정식을 선정하고 계산의 원리 및 실제 시험과정에서 발생할 수 있는 오차 요인을 고찰하였다. 또한, 각 단위수량 추정식의 계산과정에서 고려될 수 없는 실험적 요인인 분체 및 골재의 구성비나 물리특성을 변화시킨 콘크리트에 대해 고주파가열법을 통한 굳지 않은 콘크리트의 단위수량 시험을 진행하였다. 고주파 가열법를 이용한 굳지 않은 콘크리트의 단위수량 시험방법은 ± 20kg/m3의 허용오차 범위를 대부분 만족하였으나, 추정식에 따라 경향 및 오차의 크기가 차이를 나타냈다. 웻스크리닝 과정에서 발생하는 시료 편차 또는 시료 샘플링 과정에서 발생하는 굵은골재채취량 편차로 인한 추정오차의 영향을 최소화하기 위해서는 가열 건조시 콘크리트 시료를 이용하고 이후 시료의 굵은골재의 채취량 편차를 추정식에서 보정하는 방법으로 추정한 단위수량이 가장 정확한 결과를 나타내는 것을 실내 배합시험을 통해 확인할 수 있었다.

Keywords

References

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