Prediction of form demolding strength of concrete mixed with non-sintered hwangto using ultrasonic pulse velocity method

초록

This study presented a trend equation derived from regression analysis of compressive strength and ultrasonic velocity to predict the form demolding time for concrete mixed with Non-sintered Hwangto (NHT) at various replacement rates. The experimental results showed that compressive strength decreased as the NHT substitution ratio increased. Regarding ultrasonic speed, the speed difference widened as age increased until one day old but decreased when measured up to 28 days. Regression analysis revealed that plain concrete had a lower ultrasonic velocity than HC at the same compressive strength. Additionally, plain concrete reached the time for vertical, single-layer, and multi-layer horizontal form demolding faster than HC. An error test comparing the trend formula from this study with previous studies showed that this empirical formula had an average error value close to zero, indicating high reliability for predicting demolding time. © 2024 Architectural Institute of Korea.

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