Quantifying water-driven geometric uncertainties in powder bed concrete printing using high-resolution 3D modeling

TL;DR

This paper investigates how water dosage affects geometric accuracy in powder bed concrete 3D printing, quantifying deviations and proposing a digital compensation method to improve fidelity.

Contribution

It introduces a high-resolution 3D modeling approach to quantify water-induced geometric deviations and develops a pre-adjustment technique to enhance printing accuracy.

Findings

Small water content changes cause large, directional deviations.

Deviation patterns intensify with increased water content.

Pre-adjusted digital geometry improves accuracy without post-processing.

Abstract

Dimensional accuracy in powder bed 3D printing of concrete is strongly influenced by binder distribution, and the resulting geometric deviations can be direction-dependent. This study examines how voxel-wise water dosage influences geometric fidelity and deviation anisotropy. Experiments show that small changes in water content can cause large, systematic deviations, including edge rounding and swelling. We quantify these effects using high-resolution stereophotogrammetry, aligning as-built scans with CAD models. We then compute deviation metrics such as point-wise distance errors and volumetric differences across multiple water-dosage settings, revealing repeatable, directionally biased deformation patterns that intensify with higher water content. Mechanical testing indicates that stiffness and strength change only marginally, with no clear trend in the tested range. This is explained by excess voxel water diffusing into surrounding powder, leaving the effective water-cement ratio largely unchanged. Finally, we demonstrate a design-compensation concept that pre-adjusts digital geometry to counter predictable deviations, improving accuracy without post-processing.