Early-Age Strength Monitoring of Sensor-Embedded 3D Printed Structures

Concrete 3D printing (C3DP) is a new automated construction technology with a significant potential to reduce construction time and cost. The absence of formwork in C3DP exposes the freshly printed structures to ambient conditions and potentially excessive water evaporation. The freshly printed structures should be able to carry the service loads in a shorter time compared to conventionally cast concrete to make it possible to reduce the overall construction time. The destructive testing methods, which are usually time-consuming, are not ideal for this application, and nondestructive methods are preferred. This article provides a review of existing literature on the strength monitoring of concrete, with a focus on the early-age strength of 3D printed concrete. A new automated curing system was used to compare the effectiveness of three different curing conditions. Moreover, a new index for estimating the flexural strength of 3D printed concrete based on electrical resistivity and temperature history is proposed.