Title:
Synergizing UHPC and Conventional Concrete for Economic and Sustainable 3-D Printed Composite Section (Prepublished)
Author(s):
Avinaya Tripathi, Sahil Surehali, Atharwa Samir Nimbalkar, Barzin Mobasher, Narayanan Neithalath
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
3-D printed concrete; composite sections; economic structure; sustainable construction; ultra-high-performance concrete
DOI:
10.14359/51749253
Date:
10/8/2025
Abstract:
Ultra-high-performance concrete (UHPC) is composed of a high volume fraction of binder and steel fibers, and a very low water content, resulting in enhanced strength and ductility, along with higher cost and environmental impacts. This study develops a UHPC mixture amenable to three-dimensional (3-D) printing, with 30% of cement (by mass) replaced with a combination of replacement materials. The proportioned UHPC mixture with 1.5% fiber volume fraction demonstrates 28-day compressive strengths of > 120 MPa (17.4 kips), and limited anisotropy when tested in the three orthogonal directions. Furthermore, 3-D printed layered composites are developed where UHPC (with and without fiber reinforcement) and conventional concrete layers are synergistically used in appropriate locations of the beam so as to achieve mechanical performance that is comparable to 3-D printed UHPC sections. Such manufacturing flexibility offered by 3-D printing allows conserving resources and attaining desirable economic and environmental outcomes, as is shown using life cycle and techno-economic analyses (LCA/TEA). Experimental and theoretical analysis of load carrying capacity and preliminary LCA/TEA show that >50% of the fiber-reinforced UHPC beam volume (in the compression zone) can be replaced with conventional concrete, resulting in only a <20% reduction in peak load carrying capacity, but >35% reduction in cost and >20% reduction in CO2 emissions. These findings show that targeted layering of different materials through 3-D printing enables the development and construction of 3-D-printed performance-equivalent structural members with lower cost and environmental impacts.