New Frontiers

By Shadi Nazarian 

The contemporary architectural landscape is undergoing a transformation shaped by material innovation and interdisciplinary research. This article introduces a new architectural paradigm through the development of seamless transitions between glass and engineered geopolymer concrete. Drawing on advancements in the science and engineering of materials, this research proposes an alternative to complex and costly conventional joints, offering integrated and functionally graded composites that respond to structural, thermal, and optical performance criteria. By eliminating mechanical frames and chemical adhesives, this approach signals new possibilities for expressive, sustainable, and resilient architecture. 

Some of the most radical transformations begin quietly, in the chemistry of materials. Glass — typically employed as a transparent boundary framed in steel or wood — is now asserting itself not just as a surface, but as a structural and conceptual medium. We are in a moment of groundbreaking discoveries: The Glass Age. We are witnessing a surge of new and innovative explorations that reveal the latent properties and untapped potential of this remarkable material, expanding its applications.  

There is a variety of smart glass that can change its transparency in response to light, temperature, or user input, allowing for improved energy efficiency by reducing reliance on HVAC and artificial lighting, and enhanced comfort and privacy in commercial and residential spaces. Meanwhile, rapid advancements in optical fiber technology, made possible by understanding the properties of glass, have enabled faster and more efficient data transmission. Glass is now being used as an active energy generator. BIPV systems embed solar cells into façades, windows, and roofs, enabling net-zero energy buildings, and seamless integration of solar technology without compromising aesthetics. Architectural glass has been embracing environmentally conscious practices, using recycled glass during production to reduce embedded energy and emissions. Low-emissivity (Low-e) coatings and solar control glass are improving thermal performance. Ultra-thin, lightweight, flexible, and bendable Willow Glass, produced by Corning using fusion processors and sold in wide rolls, has been used to provide hermetic barriers protecting sensitive materials from moisture, oxygen, and stain. Still emerging, this innovation allows glass to repair minor scratches and cracks through heat or sunlight activation, potentially reducing maintenance costs. 

The historical evolution of glass science and technology has inspired utilitarian, creative, and groundbreaking innovations across diverse disciplines. Today, advancements in optical clarity, thermal resistance, strength, durability, and biocompatibility, combined with refined manufacturing techniques, are catalyzing new research directions and conceptual strategies at micro, meso, and macro scales. This will impact fields such as medicine, electronics, communication, and aerospace, as well as architecture and construction.  

Our research, developed in collaboration with material scientists and engineers, asks a simple question: What if glass and concrete could be joined without frames, adhesives, or mechanical joints? What if the transitional boundaries could generate new structural, thermal, architectural, and spatial experiences?  

LESSONS FROM HISTORY  

Glass has never been a passive material. Traditionally framed inside load-bearing façades, it began to assume a greater architectural role, shaping atmospheric characteristics and spatial experiences by modulating the light through color, controlled transparency, and layering. In modernism, with separation of building structure from skin, glass erased and dematerialized walls, defining a new kind of visual and spatial continuity. Arthur Korn, writing in Glass in Modern Architecture, saw the glass wall as something that “encloses and opens up spaces in more than one direction… full of mystery, delicate yet tough.” His words anticipated the aspirations of modernist architecture: to replace division with openness, to turn enclosure into atmosphere. 

Think of Joseph Paxton’s Crystal Palace, where glass panes, integrated into a lightweight iron framework, began to transfer wind and lateral loads to the main structural skeleton. The innovation lay not in the structural capacity of the glass, but in its unprecedented scale, modular integration, and its role in redefining the relationship between enclosure and structure. Recall Le Corbusier’s statement, where he declared, “With reinforced concrete, there is no need for a framing wall. The window can run from wall to wall and illuminate them all over.” While he was speaking of a literal transparency, exposure of the interior layers of space began to promote theories of phenomenal transparency in architecture, inviting a deeper gaze and an embodied experience of the depth of the building. Consider his use of horizontal windows demonstrating the freedom of the façade. Contemplate the concept of glass as a diaphragm and dematerialization of architecture, encouraged by Moholy-Nagy at the Bauhaus. These are all moments when glass suggested a future other than as a counterpoint to solid masonry. These aspirations for glass were often curtailed by the limits of assembly and the realities of fabrication. Glass was still inserted into frames, bordered by sealants, or layered in redundant systems. The ambition for continuity was real; the material logic wasn’t there — yet. 

Advancements in manufacturing have since begun to allow for massive glass panels that maximize natural light and create open, modern spaces, in addition to curved and bent glass for futuristic, fluid architectural forms. To address urban noise and safety, acoustic insulation glass has been widely adopted. Laminated and tempered glass offer protection from impacts and extreme weather.  

Driven by the most recent developments in compositions and manufacturing processes, new types of hybrid glass with tailored properties for specific applications and performance criteria have been created. Often these combine the benefits of glass and other materials, such as the polymers of ceramics, to offer improved toughness, flexibility, mechanical properties, and functionality. New manufacturing processes such as precision molding, fusing forming, and three-dimensional printing have been explored. “Glass post-processes” refer to techniques used to modify and enhance glass after it has been initially formed. These processes can improve its appearance, strength, durability, and functionality. Common post-processing techniques include annealing, toughening (tempering), coating, and various decorative methods like sandblasting, engraving, and painting.  

A DIFFERENT APPROACH 

Today, architectural assemblies have become increasingly complex. A typical window is held inside a metal frame with an array of smaller or compound joints to meet a number of functional requirements in relation to thermal, fluid, vapor, and acoustical barriers and insulating layers. Wall assemblies are layered with vapor barriers, insulation, gaskets, adhesives, and finishes — each component requiring coordination across multiple trades, each junction a potential point of failure. 

Our team’s response was to explore removing the layers and joints altogether. Could we create a continuous material system where concrete is engineered to transition into glass — not by gluing one to the other, but by developing a functionally graded material (or FGM) that gradually shifts composition, opacity, and performance. This required seeing materials not as binary conditions — transparent or opaque, brittle or dense — but as part of a spectrum. The result is a new kind of tectonic thinking: transitional rather than segmented, monolithic rather than layered. 

THE RESEARCH JOURNEY 

We began with a simple premise: Glass and concrete are kindred materials. Both can be understood through the lens of ceramics. A ternary phase diagram — a graphical representation that maps the phases of alloys with three components based on their concentration and temperature — helps determine the elemental composition of a specific point on the diagram, and how the chemistries overlap. The phase diagram of the ceramics’ family demonstrates all possible mixtures of silica sand, aluminum oxide, and calcium oxide.  

Understanding this diagram triggered a hypothesis of how we may create a functionally graded advanced ceramic — to seamlessly transition from geopolymer based concrete to soda-lime glass, by adjusting proportions of fly ash, recycled glass, and other mineral additives. 

Through iterative testing, we developed: 

• Structural geopolymer (GP) concrete with a thermal expansion profile compatible with glass 

• Cast and sintered specimens using recycled materials 

• A post-processing method (annealing and ceramization) to unify the piece with controlled permeability for insulation and impermeability where needed  

Since 2015, we have produced a number of casted unibody prototypes that transition from metakaolin-based GP concrete to glass, from fly ash or slag-based GP concrete to glass without mechanical fasteners or adhesives. Testing our increasingly larger specimens — some over 21 inches — we have demonstrated structural integrity and insulative performance. We use varying areas of density to increase thermal and acoustic insulation properties where desired, increase structural capacity where needed, and adjust visual transparency to enable penetration of natural light and view. It is important to carefully control the percentage of each constituent during the stages of casting and post-processing in the furnace. It is critical to anneal the glass to reduce its inner stresses, making it more durable and less prone to cracking or shattering. Equally critical is to have control over the firing schedule during sintering, which is a post-processing technique used to strengthen and densify the composition of the functionally graded mixture to create a monolithic unibody from the assembly of recycled materials (which includes glass cullets, processed and powdered geopolymer binders, and others).  

After gaining control over the creation of a seamless transitional interface between GP concrete and glass, and precise distribution of varying properties to enable graded transition along and through a wall, we have adjusted our mixtures to develop the needed rheology (form and flow) for 3D printing at laboratory scales. Some iterations of our work were intentionally sculptural, enabling public engagement and tactile understanding of the material transition. Others were optimized for architectural application. 

ARCHITECTURE WITHOUT LAYERS 

The ongoing research unlocks a new set of spatial and environmental possibilities: 

• Picture windows embedded within material, transitioning from the opaque concrete to areas of optical transparency inside walls 

• Wall systems with porous insulating cores and impermeable surfaces 

• Continuously cast panels that are structural, insulative, and transparent exactly were needed 

The material itself becomes the means of detailing. There is no trim, no reveal, no flashing. Instead, architecture emerges from gradation — from the slow shift in material behavior and perception. Because these elements could be produced from recycled or locally sourced materials, and require fewer trades to assemble, they also offer reduced embodied and operational energy; higher resilience to heat, cold, and corrosion; and lower longterm maintenance and environmental cost. In effect, this is not just a new material — it is a new way of building. 

THE BROADER VISION 

This work was recently recognized among the “40 Most Disruptive Penn State Technologies” by the Invent Penn State Innovation Guide. Our next step is to move beyond the lab. We are preparing to scale this method for architectural applications by testing full-wall assemblies and developing details that align with code, cost, and craft. More importantly, we see this as a chance to reimagine how materials meet, not just as a technical achievement, but as a philosophical one. 

The joint has always been a site of compromise, of negotiation. What if, instead, it became a zone of transformation? A place where one condition does not end abruptly, but evolves? 

SHADI NAZARIAN is a professor and the inaugural Ralph Hawkins, FAIA Endowed Chair at the School of Architecture, College of Architecture, Planning and Public Affairs, The University of Texas at Arlington. Nazarian’s work bridges experimental material science and design culture. Her research explores the expressive and structural potential of engineered advanced ceramics, glass, and concrete. 

CAPTIONS: 

Joseph Paxton’s Crystal Palace, London, 1851  

PHOTO: PHOTOS: HTTPS://WWW.EBAY.COM/ITM/133594001221  

Le Corbusier’s Studio Apartment, Paris, 1931  

PHOTO: HTTPS://WWW.METALOCUS.ES/EN/NEWS/LE-CORBUSIERS-PARIS-APARTMENT-STUDIO-REOPENS-ITS-DOORS-PUBLIC  

A successful lab-scale prototype from 2018, this sculptural piece demonstrates a graded transition from glass to geopolymer concrete embedded with fine igneous rock aggregates. Titled “Making Hands,” a nod to Escher’s Drawing Hands, the work captures a paradoxical interplay: Glass and concrete not only shape one another but also reveal their true natures through an entangled and ironic material relationship between what they are and what they create.  

PHOTO:  SHADI NAZARIAN (TOP RIGHT AND LEFT);  

[a] A transitional specimen showing seamless gradation from geopolymer concrete to glass (original Sample, six inches in length)  

PHOTO: CODY GODDARD

[b] A 3D MicroCT Scan of the same specimen showing pore connectivity, closed porosity at the bounding surface, and successful transition between glass and GP concrete  

PHOTO: CODY GODDARD 

[c] and [d]: Scanning Electron Microscopy (SEM) images showing microstructural details of the interface between MK-based GP and soda-lime glass after firing at 850°C  

PHOTOS: CENTER FOR QUANTITATIVE IMAGING AT THE PENNSYLVANIA STATE UNIVERSITY AND MATERIAL CHARACTERIZATION LABORATORIES, AT THE PENNSYLVANIA STATE UNIVERSITY