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In order to investigate the influence of carbonation treatment on the rebound strength measurement curve of machine-made sand concrete, this study conducted research on the carbonation mechanism sand concrete rebound strength measurement curve through rebound and compressive strength tests using carbonation degree and concrete strength grade as control variables. The results showed that in the short aging period, carbonation treatment had little effect on the compressive strength of manufactured sand concrete but could cause an increase in the rebound value measured by the high-strength and heavy rebound hammers. As the strength grade of the manufactured sand concrete increased, the rebound value measured by both the high-strength and heavy rebound hammers increased accordingly. Compared with the high-strength rebound hammer, the heavy rebound hammer had higher accuracy in detecting the rebound of the carbonated manufactured sand concrete. This study established measurement curves for uncorrected and corrected carbonation depths, among which the accuracy of the corrected carbonation depth measurement curve was higher. At the same time, this measurement curve has been applied to the rebound test of the Pinglu Canal Extra-Large Bridge Project in Guangxi, China, and its practicality and reliability have been verified. [ABSTRACT FROM AUTHOR]

Concrete with manufactured sand (MSC) requires adequate compressive properties, which may be caused by stone powder. This present study investigated the effect of different stone powder content (0%, 3%, 5%, 7%, 9% and 11%) on compressive properties of MSC. The properties of fresh MSC were evaluated by three tests, compressive strength, axial compressive strength and elastic modulus. Measure results showed that stone powder as part of fine aggregate replacement improved compressive properties of MSC. The content ranging from 5%–7% increased compressive strength. The content of 11% could greatly improve axial compressive strength. The elastic modulus had a slightly enhancement when the stone powder was within 9%. Predictive models were proposed for the prediction of long-term compressive strength of MSC. [ABSTRACT FROM AUTHOR]