Sessions & Events

 

All sessions and events take place in Central Daylight Time (CDT).
All events take place at the Hyatt Regency New Orleans.

On-demand sessions will be available for viewing in the convention platform/event app under "On-Demand Content" within 24-48 hours of the session premiere. Please note, on-demand sessions are not available for CEU credit. *Denotes on-demand content.


Application of Nanoparticles in 3D Printed Concrete, Part 2 of 2

Tuesday, March 26, 2024  11:00 AM - 1:00 PM, Strand 11B

Nanoparticles (such as nanosilica, nanoclay, etc.) are used as viscosity modifying agents (VMA) or thixotropic agents to alter rheological properties of 3D printed concrete (3DPC). Nanoparticles can also act as seeds for CSH nucleation to accelerate cement hydration. As a result, nanoparticle-modified 3DPC can possess not only appropriate extrudability and flowability but also proper segregation resistance, shape retention, and buildability for consistent and quality printing. Nanoparticles are also used to densify microstructure and improve the interlayer bond of 3DPC, thus increasing strength and enhancing durability of the 3DPC products. The objectives of this technical session are to (i) summarize recent progress on the use of nanoparticles in 3DPC, (ii) better understand the potential roles of nanoparticles in enhancing the properties of 3DPC, and (iii) discuss perspectives and challenges with the use of nanoparticles in 3DPC.

Learning Objectives:
(1) Build skills in improving rheological properties of 3D-printed concrete (3DPC) through nanoparticle modification;
(2) Develop an understanding of the key issues in the 3D printing process of nanoparticle-modified 3DPC;
(3) Investigate innovative techniques for 3D printing of ready-mix concrete containing nanoparticles;
(4) Evaluate the advantages associated with the utilization of nanoparticle-modified 3DPC in enhancing concrete sustainability.

This session has been approved by AIA and ICC for 2 PDHs (0.2 CEUs). Please note: You must attend the live session for the entire duration to receive credit. On-demand sessions do not qualify for PDH/CEU credit.


3D Printing with Conventional Ready-Mix Concrete and Nano Particles

Presented By: Tyler Ley
Affiliation: Oklahoma State University
Description: This presentation will show a new method to 3D print concrete that uses a new technique to 3D print ready mix concrete. The equipment is an inexpensive hopper and auger that extrudes concrete into a moving forming box. The concrete mixture uses a ready mix concrete mixture that uses 1" maximum nominal aggregates and functionalized nanoparticles to control the rheology of the concrete. These nano particles are not commonly used in concrete but are commercially available. Several rapid mixture evaluation methods will also be presented. This technology has been used to print walls that are 30' long and up to 8' high. Plans to extend and automate the equipment will be presented.


Enhancing Rheological Properties Through Targeted Nano-Infusions for Better 3D Printing Control

Presented By: Narayanan Neithalath
Affiliation: Arizona State University
Description: Rheology control is important for 3D printed concrete mixtures. Particle packing is influential in rheological control. This work discusses approaches to enable better rheological control through size-differentiated particles. Limestone of multiple sizes (as fillers that do not interfere much with hydration) and graphene (that alters hydration characteristics and products) are used. The work determines pathways to incorporate these materials with an overall view of enhancing fresh (and if possible, hardened) properties of 3D printed concretes.


Improving Printability and Sustainability of Cementitious Mixtures Using Cellulose Filaments

Presented By: Ahmed Omran
Affiliation: Massachusetts Bay Transportation Authority
Description: Additive manufacturing of concrete, often called 3D Concrete Printing (3DCP), has gained significant attention in construction industry due to its various advantages over conventional construction. The 3DCP eliminates the need for formwork and molds, allows the design and fabrication of many shapes and geometric features, and enables incorporation of additional functionality into a structure. As a result, it has a potential to achieve substantially by reducing the construction time and labor cost, enhancing safety and reliability, and minimizing the environmental footprint of concrete industry. However, there are several challenges that this emerging construction technology faces. One such challenge is that printable mixtures demand high cement and admixture contents to satisfy the opposing requirements of extrudability such as high flowability, and buildability such as high stability. Plant-based nano materials, as cost-effective and sustainable materials, can provide advantageous rheological and mechanical characteristics when included in printable mixtures. This study explores the effects of nano cellulose filaments (nCF), a relatively new type of nanocellulose material, on the printability characteristics such as extrudability and buildability of cementitious mixtures. First, mortar mixtures with varying ratios of nCF are prepared. The rheology of the mixtures containing nCF is thoroughly assessed using a shear rheometer with a building materials cell and vane motor. Two testing protocols are followed: ramp test and stress growth test. A ramp test is conducted to determine dynamic yield stress and plastic viscosity using Bingham visco-plastic material model. For this purpose, a shear rate ramp-up from 0 s-1 to 100 s-1 is applied for 30 s followed by a shear rate ramp-down from 100 s-1 to 0 s-1 for 30 s. Stress growth tests, where a constant increasing strain at a constant shear rate is applied and the shear stress build-up with time is monitored, and carried


Develop a Low-Carbon 3D Printing Concrete Mix using Cellulose Nanomaterials

Presented By: Linfei Li
Affiliation: University of Maine
Description: While numerous benefits of incorporating nanomaterials in concrete have been identified, the construction industry has limited applications due to various hurdles. The most significant challenge encountered when utilizing nanomaterials in concrete is their high cost. Even the addition of a minor dosage (3 cwt%) of nanosilica to the matrix results in concrete costs increasing by a factor of 10. Another deterrent is the marginal improvement in mechanical performance and durability of the concrete. Although many nanomaterials exhibit exceptional mechanical prowess and can theoretically create a "filler effect" within concrete, the marginal improvement in mechanical performance and durability in concrete has been found because of the poor dispersion. On the other side, nanomaterials could potentially be a good fit for 3D printing concrete (3DPC) because they can change the rheological properties of concrete with only a small dosage without considering the dispersion challenge. In this study, a low-carbon 3DPC mixture is developed from a novel carbon-reductive cementitious mixture with affordable, nature-based cellulose nanomaterials. This undertaking is set to catalyze the progression of diverse nanomaterials into new markets, generating an unprecedented surge of momentum.


A Convergent Approach for Monitoring Fluid to Solid Transition in 3D Printing Using Adaptive Rheology and Electrochemical Impedance Spectroscopy

Presented By: Panagiotis Danoglidis
Affiliation: University of Texas At Arlington
Description: A convergent approach for using in-situ rheological and Electrochemical Impedance measurements allows for unique information about the material’s structure, hydration kinetics and evolution of rheological parameters. Nanoscale carbon fibers, due to their extraordinary intrinsic conductivity, are ideal candidates for tuning the electrical properties and hydration kinetics of complex fluids, such as cementitious nanocomposites, at fresh state. In this presentation, we will show experimentally that dielectric permittivity accurately reflects changes in rheological properties from fluid-to-solid as stiffness increases.


Sustainable Cementitious Materials Containing Cellulose Nano Materials for Concrete 3D-Printing

Presented By: Yu Wang
Affiliation: Purdue University
Description: Cellulose nanomaterials (CNMs) are a class of biodegradable substances highly prized for their intrinsic non-toxicity and cost-effectiveness. Sourced from renewable materials, CNMs have attracted interest in recent research, particularly for their capacity to alter the rheological properties of cementitious materials. This emerging potential positions CNMs as a sustainable and cost-effective viscosity modifier in the 3D printing industry. Moreover, recent research has explored CNMs' multifaceted benefits, implying their capacity to accelerate the hydration process and optimize pore structures. Such improvements in the material matrix yield enhancements in both mechanical and transport properties of cementitious materials. This presentation will provide a comparative analysis, examining the buildability and rheological properties of mortars incorporating CNMs in contrast to those using other viscosity-modifying additives. The hydration kinetics and mechanical properties of the 3D printing mixture will also be presented. This incorporation has the potential to develop a sustainable and cost-efficient concrete mixture with enhanced rheology, mechanical, and durability performance for 3D printing applications.

Upper Level Sponsors

ACI Northern California and Western Nevada Chapter
Baker
Conseal
Euclid Chemical
FullForce Solutions
Master Builders
Natural Resources Research Institute - University of Minnesota
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