Designing Permeable, Self Healing Pavement That Nourishes The Environment
By Sarah Ikerd, Studio Shangri-La Multimedia, July 2025
Sarah.ikerd@studio-shangri-la.com
www.studio-shangri-la.com; https://www.researchgate.net/profile/Sarah-Ikerd
Figure 1: Basic Layers & Process
Abstract
Drawing from both natural chemistry and bio-inspired engineering, next generation regenerative pavement reimagines infrastructure as a living ecosystem partner. Made from layered travertine, lava rock and microbial agents, modular tiles interlock via simple tongue and groove joints, and interface with breathable bentonite slip to stabilize and fertilize the underlying soil, as well as sequester carbon and filter stormwater. This system heals itself naturally through microbial calcite precipitation, absorbs water, supports plant life, and can be deployed rapidly using either precast tile modules, or a companion regenerative mineral paste. They can transform urban surfaces into soil-restorative networks that collaborate with the Earth, rather than compete with it. This pavement isn’t just new a materials product design. It’s part of a new mindset that regards mineral logic and nature’s intelligence, hewn over millennia. (1)
Figure 2: Molten basalt lava flow – Wikipedia
The Main Materials
Lava rock (Basalt) and Travertine offer valuable geological contrast in that both carry deep symbolic and functional potential. What makes them so compelling for alternative pavement is firstly, composition. Rich in magnesium and iron, Lava rock (basalt) typically is also composed of silicon, oxygen, and aluminum, as well as other ultramafic or igneous minerals common to earth’s mantle.
Its texture is fine-grained and highly porous, due to the gas bubbles that escape during cooling. Next, lava’s thermal properties are excellent for heat retention and insulation—one reason why it’s used in saunas, for example. As for environmental use, it acts as a natural filter in water systems and can support plant growth due to its porosity and mineral content. In this context of pavement, it’s lightweight and durable—which is ideal for permeable layers that minimize environmental interference and even nourish the earth. (2)
The formation of Travertine (Calcium Carbonate) is precipitated from mineral-rich water, especially around hot springs. The porosity is naturally high, making it excellent for water permeability and soil interaction. As for the soil fertilizing potential, it releases calcium ions into the surrounding soil, and can buffer pH along with supporting microbial activity. Travertine is quite well known for aesthetic & structural use, famously used in classical Roman architecture, such as the Colosseum and aqueducts. (3)
Figure 2: The longstanding Roman Colosseum features Travertine; credit: Wikimedia.
Synergy
Lava brings strength, porosity, and mineral richness; Travertine offers regenerative chemistry and a soft, earthy aesthetic. Together, they can form a layered or mixed pavement system. The Lava base is for drainage and microbial support; the Travertine is aesthetic, calcium-rich, and regenerative. The substrate is a bio-enhanced binder that contains healing agents or bacteria. Here, Agent Sporosarcina pasteurii is selected for its environmental resilience.
The beautiful simplicity and synergy of this structure allows healing to occur from the inside out, with cracks triggering a cascade of microbial and mineral responses.
Environmental activation healing is triggered by rainwater or humidity that activates microbes and mineral exchange. It’s also triggered by temperature shifts and lava rock retains heat, which can stimulate microbial activity. Then pH changes cause cracks that expose new surfaces, shifting local chemistry and activating healing agents.
Figure 3: Travertine Orb, photo by the author
Self-Healing Mechanisms
Microbial Calcium Carbonate Precipitation (MICP/Bio-Grouting):
Travertine is rich in calcium carbonate, which can be reactivated through microbial processes. One could introduce urease-producing bacteria into the porous layers. When cracks form and moisture enters, bacteria trigger calcite precipitation, sealing the gaps. This mimics natural travertine formation, essentially regrowing the stone from within. (4) (5)
Mineral Cycling from Lava Rock:
Lava rock’s porosity and mineral content make it ideal for hosting microbial colonies that aid in healing. It acts as a reservoir for magnesium, iron, and silicates, which can participate in mineral bonding and surface regeneration, and supports moisture retention, which activates healing cycles.
Figure 4: The Rock Cycle – Geology
Microbial Agent
Sporosarcina pasteurii is ideal because it produces urease, an enzyme that breaks down urea into carbonate ions. And very importantly here, it facilitates microbial induced calcite precipitation (MICP), forming calcium carbonate bridges in cracks and porous zones. That fact that it thrives in alkaline environments would work well with this travertine-based system.
In this regenerative pavement it would be incorporated as powder, and activated with moisture and nutrients (e.g., urea, calcium salts). Agent S. pasteurii would work synergistically with the other ingredients — bentonite, lava minerals, and travertine calcium. (6)
Figure 5: Sporosarcina pasteurii – Alchetron, The Free Social Encyclopedia.
– Travertine Matrix Embedding
Embedding the microbes into the travertine mix turns the tile body into a slow-release microhabitat, which is ideal for long-term, passive activation. Over time, they awaken with moisture and urea exposure. This provides the structural integration of microfractures that can be biologically healed. (7)
– Bentonite Interface Embedding
Adding microbes to the bentonite slip layer allows for active and immediate biological engagement with the soil. Here they accelerate calcite sealing of tile seams and support subsurface bonding. This promotes edge protection and maintaining soil-tile integrity, especially in high-stress installations. (8)
Reaction Pathway: Urea + Calcium = Calcite + Ammonium
When moisture activates the tile or bentonite layer, urea is hydrolyzed by the microbe’s urease enzyme, producing:
Carbonate ions → combine with calcium to form calcite (CaCO₃)
Ammonium ions → absorbed by the microbe for growth and energy
S. pasteurii gets both its building material (carbonate) and its nutritional fuel (ammonium) from this single reaction. The embedded microbes are not just surviving, they’re thriving on the reactions of the design. (9)
– Microbes In The Tile & Powder Matrix
Travertine or lava / basalt powder provides a porous, mineral-rich habitat. Embedded urea and calcium salts ensure the reaction can occur. Then, moisture (from rain, humidity, or installation) activates the microbes. The result is that microbes wake up, eat, and then build — no external feeding is required. (10)
– Bentonite Layer Support
If microbes are also in the bentonite they get moisture faster, triggering immediate calcite sealing at the seams. Ammonium from urea hydrolysis is also retained longer in the clay matrix, supporting microbial metabolism. (11)
Figures 6 & 7: Simple staggered squares and hexagonal honeycomb pattern for tile-based installation.
Installation
Modular Tile System
The first method of installation is having precast units with interlocking edges for rapid placement. Figures 4 & 5 show staggered squares and hexagonal patterns for simplicity and stability, as well as ease of manufacturing. Each tile would contain embedded lava and travertine layers for targeted multifunction. This also means easy replacement of sections without heavy equipment or disruption. The dimensions could be 6×6 feet on a flat grade, or 3×3 feet per tile for flexibility.
Dry Blend Paste
– Travertine Powder (CaCO₃): Fertilizes soil, supports microbial healing. Fine grind improves dispersion and reactivity.
– Lava (Basalt) Ash / Dust: Adds porosity, minerals (Mg, Fe), microbial support. Enhances thermal properties and water retention.
– Sodium Bentonite Clay: Binder, swelling agent, crack-sealer. Expands with moisture, seals gaps, hosts microbes.
– Optional Additives include: Microbial inoculants, natural latex, clay slip.
This mix would be delivered as a dry blend that’s activated on-site with water—making it easy to transport and flexible for different installation methods. Both of these formats signify low-energy installation protocols, the materials designed to cure or bond without high heat or toxic adhesives. They use gravity-fitted layers and natural binders like clay-based slips. Overall, this reduces carbon footprint and encourages community-scale deployment. (12)
Regenerative Pavement Paste, Ratio By Volume
Travertine Powder (CaCO₃) – 2 parts.
Soil fertilization, microbial calcite source.
Lava (Basalt) Dust / Ash – 1.5 parts.
Porosity, mineral enrichment, microbial habitat.
Sodium Bentonite Clay – 1 part
Binder, swelling agent, crack sealing.
Water – ~0.5–1 part (adjustable)
Activation and spreadability.
Optional Additives: 0.1–0.2 parts
Microbial inoculants, or biochar, clay slip, natural latex.
This 2:1.5:1 ratio gives a mineral-rich, porous, and biologically active paste that can be applied by trowel, roller, or spray. Water content can be adjusted based on climate and application method. (13)
Deployment Notes
Dry mix option: Can be shipped as powder and activated on-site with water.
Curing time: ~24–48 hours depending on humidity and temperature.
Spread thickness: ~1–2 cm for overlays; thinner for crack filling.
Shelf life: Dry mix can last months if stored airtight and moisture-free.
Carbon Sequestration & Stormwater Filtration
Beyond its structural and regenerative strengths, the basalt–travertine mix offers significant environmental co-benefits. Basalt, rich in reactive silicates, actively participates in carbon sequestration through enhanced weathering—capturing atmospheric CO₂ and converting it into stable carbonate minerals over time. Simultaneously, the porous nature of travertine and the mineral permeability of basalt promote stormwater infiltration and groundwater recharge, reducing surface runoff, filtering pollutants, and supporting hydrological resilience. Together, this is a powerful mineral duo for sustainable infrastructure. (14)
Figure 8: Rock Cycle (Holt Science and Technology Earth Science)
Materials Synthesis
Fortunately, the main materials are naturally available in numerous locations. However, it’s possible both Travertine and Basalt could be synthesized, with the synthesis of basalt from alluvial silt beginning in ancient Mesopotamia. (15)(16) It’s possible one day soon, that the synthesis of many minerals could be achieved by following the rock cycle and adding in corresponding microorganisms.
Future Vision
Both cubic and hexagonal forms are common to crystallization of minerals, such that over time, this combination and others for regenerative pavement, may make it possible for a more sculpturally integrated landscape. The roadways and thoroughfares, and even the technologies they support, could become more of an extension of nature’s patterns. And nature’s patterns could be conscientiously trained for a cohesive and synergetic interface. Roads being more like terraced growths or outcroppings of the land is but one fascinating example among many exciting possibilities of better understanding earth science and dynamics, and cooperating with geologic formations.
Conclusion
Travertine is formed by water and time, a symbol of luxury, legacy and enduring solution; Lava is born of fire, and symbolic of dynamic transformation. Together, they create a pavement that endures and evolves. These materials additions aren’t just alternative — they’re harmoniously multifunctional at every scale. In addition to reducing paved surfaces, they support the goal of replacing toxic, oppressive pavements with living infrastructure that respects and nourishes water flow, soil health, and plant life. (17) Pavement doesn’t have to suffocate the planet — it can collaborate with it. Infrastructure should not dominate Earth — it should collaborate with it as a living organism.
References
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