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Solar Decathlon 2017

CRETE house construction in Denver

CRETE house is a model for ad­vanced building technology, resiliency, and livability. The project is designed as a demonstration of integrated innovative precast concrete panelized system used in single-family homes, as a compelling alternative to traditional wood light frame construction. High Performance precast concrete structures are inherently resilient, protecting against fire, moisture and mold, insects, seismic events, extreme weather conditions and man-made phenomena such as blasts, force protection and acous­tic mitigation.

 

Team WashU’s CRETE house developed from the belief that innovation comes from a holistic perspective on building technol­ogy, resiliency, and livability. This approach starts with a building enclosure system that is inherently protective of its inhabi­tants. Our choice of UHPC (Ultra High Per­formance Concrete) on the outside face of the wall panels allows for a longer life cycle than typical construction materials; it utilizes a wall section which cuts down on material usage and weight, allows a faster and more accurate construction process, and gains flexibility in design.

 

Additionally, the design of the house fo­cuses on self-sufficiency in terms of energy, water and food production, supporting a hydroponic system built within the gutter system of the house. CRETE house maximizes the performance of the concrete mass in terms of its thermal, system integration, structural and aesthetics properties. This house uses durable and insulated robust precast concrete panels manufactured in a factory and assembled on-site.

 

For Crete House, Team WashU developed a precast concrete sandwich panel for the exterior walls, which consist of 4” of standard concrete for the interior wythe of the assembly, 5” of insulation and 1.25” ultra-high-performance-concrete (UHPC) exterior wythe. The thin exterior layer provides the possibility of unlimited configurations with geometries and variable thicknesses, which are not possible with traditional concrete panels. It also significantly reduces the overall thickness and weight of the wall as compared to traditional precast sandwich panels which lowers the overall embodied energy as well as the cost and energy related to shipping and handling the panels to the jobsite.

 

We developed a system using Ductal, a specific Ultra-High-Performance-Concrete (UHPC) with exceptional mechanical properties and characteristics adapted specifically to the building envelope. Ductal is a very dense, high quality cementitious material and it is defined by its exceptional high strength and durability. The material provides compressive strengths up to 29,000 pounds per square inch (psi) and flexural strengths up to 7,000 psi. It is six times stronger in compression, when compared to traditional concrete. This allows thinner and lighter structures. In addition, UHPC’s inherently waterproofing characteristics makes it a very viable alternative for exterior layer of the building’s envelope. UHPC performs well in terms of abrasion and chemical resistance, freeze-thaw, carbonation, and chloride ion penetration. “Based on ion transportation predictive modeling, it would take 1000 years for UHPC to have the same level of chloride penetration as high-performance concrete would have in less than 100 years. The potential for building façades with a millennium-long design life (along with little to no maintenance and less environmental impact over time) is a huge paradigm shift from the way sustainable infrastructure is viewed today.”[1]

 

For this project, Washington University in St. Louis has collaborated with the Precast/Prestressed Concrete Institute (PCI) and specifically the following PCI Members: Gate Precast, Ductal Lafarge North America Inc., Dukane Precast, St. Louis Prestress Inc., Wieser, Lambard, Rocky Mountain Prestress, EnCon United/Stresscon Corporation, Ben Hur and Gibbons Erectors.

 

Faculty Leaders

Yin, Hongxi / Faculty Project Leader

Moyano Fernandez, Pablo / Faculty Project Designer

Ryan Abendroth: Faculty Project Manager

Michels, Tim / Faculty Building Systems Specialist

 

Staff

Henry, Chad / Financial Manager

Meyer, Debbie / Corporate Relations Specialist

Chazen, Courtney

 

Student team for construction at Denver

 

Callahan, Dylan Weber

Miller, Ethan

Barnstorff, Adam

Keating, Clayton

Lustig, Alex

Avalos, Percy

Goldberg, Adam

Wang, Bruce

Zhu, Jian

Qian, Yanan

Lan, Tian

Li, Tian

She, Ke (Kathy)

Ding, Yike

Li, Yigang

Wurm, Nick

Hampton, John

Pabjan, Kinga

Laverde, Jairo

Mallon, Shannon

Malone, Amanda

Kohnstam, Deanna

Lai, Melinda

Darmawan, Austin

Erb, Sarah Beth

Shafran, Margot

Murray, Laura

Bhat, Nitish

Davis, Sarah

Moss, Halie

Vanecek, Jess

Treacy, Ryan

 

 

[1]  G8WAY DC, Ultra-high performance concrete has it covered, by Kelly A. Henry and Bill Henderson.