Title: Effect of Drying Environment on Mechanical Properties, Internal RH and Pore Structure of 3D Printed Concrete

Author(s): Zhang

Publication: Web Session

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Appears on pages(s):

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DOI:

Date: 3/28/2022

Abstract:
3D printed concrete (3DPC) is fabricated by depositing printable materials without formwork which increases the exposed surface to environment, and by default, eliminates the curing procedure. As a result, moisture evaporation from printed concrete mitigates the hydration of cement and impacts the development of mechanical properties. In this study, we evaluated the effects of drying (RH=60%±5%), wind (3 m/s) and exposed area on mechanical properties of 3DPC. Furtherly, the internal relative humidity evolvement was measured by humidity sensor and the pore distribution was evaluated by X-ray computed tomography. We found that curing condition had significant influence on compressive and flexural strength development for both of samples cut from printed elements and casted samples but had less significant effect on splitting tensile strength. Furthermore, samples cut from printed elements were more sensitive to curing condition when compared with casted samples. Evidence on the pore structure seemed to explain the difference: the pore connectivity increased, and the pore distribution varied for samples cut from printed elements. We also confirmed the existence of anisotropy for samples cut from printed elements and found that it did not aggravate in drying and wind conditions.