NEED MORE INFO? QUICK QUESTION
A specialist advisor will get back to you asap.
Executive summary
Renolith nanotechnology improves the resilience of road pavements and reduces the cost of construction. Various independent clients and researchers have found the construction cost savings to be in the range 15%-60%. For a typical Australian rural sealed road, the cost savings are estimated at 40%-50%.
Why Renolith? Business case overview
Stabilisation is the improvement of a soil or pavement material, usually through the addition of a binder. In-situ recycling of pavement material via stabilisation with cement is a sustainable and cost-effective approach to the construction of road pavement base layers. However, the approach has technical limitations – notably the risks of shrinkage cracking and fatigue cracking and the limited range of viable materials.
Renolith 2.0 is a nanopolymer admixture. Its super-pozzolanic behaviour significantly improves the engineering properties of cementitiously bound materials and reduces the risk of shrinkage cracking. It enables a resilient pavement base layer to be constructed from any inorganic soil or recycled material. The process creates no waste, uses up to 100% recycled materials and has a low carbon footprint.
Renolith nanotechnology has been proven in more than 70,000,000m2 of pothole-free roads around the world. Early Renolith pavements are still in good condition after 15-25 years with no signs of deterioration. Many of these pavements have experienced extreme conditions (eg. high fatigue loading, freeze/thaw cycles, monsoonal flooding).
What does a road usually cost?
The value of a road varies greatly depending on the context. The range of potential values is illustrated in BITRE information sheet – Growth in the Australian Road System.
Table 1 gives estimates of the current [2015] value of the different road types and the value of each road type in value equivalent lane kilometres. It can be seen that a lane-kilometre of dirt road in the outback is set equal to $150, or .001 lane kilometre equivalents, while a lane kilometre of a metropolitan paved tunnel is valued at $120 million, or 800 lane kilometre equivalents.
The conceptualisation associated with the value equivalent lane kilometre measure allows an understanding of some of the problems associated with road infrastructure, such as the growing trend in the value of the investment, and the associated increasing costs for maintenance, for reconstruction and for new construction to expand the network.
The ’value’ of a road is not the same as the cost of construction, but they do correlate. Also, costs change over time. In the post-COVID years, Australia has seen a huge increase in the cost of building infrastructure, resulting in cost blowouts. Some types of roads are affected more than others, as shown in the table below (Source: IPWEA forum).
Construction cost savings with Renolith – theoretical example
The example below shows the approximate cost (in 2024 $AUD) to build/rehabilitate a typical rural sealed pavement, using the cost estimation tool at https:/renolith.com.au/resources/
The calculated cost is $46 per sqm. This is roughly half the cost of $92.20 per sqm estimated by Albury City Council for a Rural Sealed Pavement.
In practice, the construction cost of a Renolith-enhanced cementitiously stabilised pavement will vary depending upon various factors such as the quality of the in-situ material, traffic loading, CBR of subgrade etc. In an adverse scenario, these factors might add $5-$10 per sqm to the cost. At $56 per sqm, this is still 39% less expensive than the $92.20 baseline.
Construction cost savings - evidence
Numerous papers and case studies have confirmed a lower cost of construction with Renolith-enhanced cementitious stabilisation compared to alternate methods. Construction cost savings of between 15% and 60% have been reported by various independent parties as shown in the table below.
Statement |
Construction cost saving |
Source |
Source type |
|---|---|---|---|
Following the early identified success of this construction technique at trial equestrian events prior to the Sydney Games, we subsequently used cement stabilisation with Renolith as our pavement construction process for all types of vehicles and pedestrian all weather access from heavy vehicle roads and parking facilities to pedestrian paths. We are satisfied that our investment in this construction at all venues in Sydney, represents a saving of approximately 60% of the cost of conventional construction of such roads and the associated time saving of up to 50% of conventional construction time. These savings have been advantageous in the preparation, management and coordination of the Overlay Works for the Sydney Games. | 60% | Testimonial | |
The Renolith product when mixed with cement and stabilised appears to be the most efficient and cost-effective product for the upgrading of soil pavement roads, and especially those where a continuous construction output can be achieved. The rate of construction is dependent on only the availability of materials at the site, eg. cement, Renolith and water, and the capabilities of the plant and expertise of the operators of that plant assigned to undertake the roadworks required. | not stated | Trial report | |
The developed designs and technologies for the construction of embankments in permafrost and in swamps using geotechnical holders filled with unsuitable soils (thawed and frozen waterlogged peat and clay soils) can reduce the volume of work and the cost of construction by 30-50% while increasing the service life of structures. The encouraging results of improving the physical and mechanical properties of reinforced soils were obtained. The most interesting is the additive “Nano Terra Soil” (Germany) [aka Renolith]. | 30%-50% | Academic paper | |
Technical and economic calculations, taking into account the actual production costs, have shown that the use of layers of fortified local grounds instead of equivalent in strength bases of imported stone materials leads to a decrease in the total cost of construction by 20-60 %. | 20%-60% | Academic paper | |
For the cost comparison we have designed flexible pavement of varying traffic intensity such as 2 msa, 5 msa and 10 msa according to IRC37:2001. [A] one kilometre long road pavement is designed, having 2 lanes of 7.5m wide carriageway and 12.5m wide road pavement…. With the use of Renolith, about 15 to 28% reduction in the cost of pavement construction can be achieved. | 15%-28% | Academic paper | |
Cement additives are normally successful under most circumstances, but very expensive. Renolith has been applied successfully in areas, where construction material was not available, by the utilisation of the in-situ material. In several cases pure sand and even clayey material were used to construct base courses successfully. Although the initial cost of the product seems to be high, savings of almost 40% on the construction of pavement layers were generated, because no construction material of whatever nature was imported. | 40% | Specification | |
Renolith technology has been used in some projects by the Public Works Department of Arunachal Pradesh State in India and reported cost reduction of about 20 to 30% in different pavement construction projects. In Nagaland, a stretch of road leading New Secretariat road in Kohima has been constructed using Renolith. No failure has been observed for last two years and certified to meet to all necessary standards and specifications set by Nagaland PWD. | 20%-30% | Academic paper | |
The aim of this work was – to determine the optimal types and a ratio of components of soil – cement mixes whose properties can be efficiency modified by using Renolith technology up to level that must be achieved in accordance with designed projects (taking into account economical factors). This complex includes mechanical properties and their stability, flexibility, relaxation properties for long working time and, as result, increasing the cracking resistance; water resistance; weather (climate) durability and possibility of using in-situ soil for bottom construction (landfill, compost site, …) and waterproof construction (embankment, road shoulders, …). The conclusion from our data … is as follows: It is possible… to achieve significant economical | not stated | Laboratory investigation | |
...NanoTerraSoil (aka Renolith] for roads, which is built into the base layer and prevents water penetration. The result: the asphalt holds up better because the base layer does not break or tear open in the worst frost or extreme heat. "The construction costs are reduced by 30%" says Dr. Scheele | 30% | News article | |
The operators of the Brenner Autobahn give the innovative process excellent testimonials: | 30% | News article | |
With the use of Renolith, about 20 to 40% reduction in the cost of pavement construction can be achieved. There is no need to import an aggregate of required specification, hence locally available material can be used. Renolith provides adequate flexibility and durability to the pavement and avoids the formation of cracks. | 20%-40% | Academic paper |
Construction cost savings – technical principles
Austroads Guide to Pavement Technology Part 4D: Stabilised Materials (AGPT04D-19) states:
The use of stabilisation technology for stabilising and recycling materials for pavement construction and maintenance is widely accepted as a cost-effective method of improving long-term performance and reducing whole-of-life costs of modern, heavily-trafficked pavements.
Various stabilisation techniques are possible, such as lime, chemical, mechanical, foamed bitumen and cementitious. Each has its advantages and limitations. Insitu cementitious stabilisation is common and very cost-effective. However, per Austroads AGPT04D-19:
Cracking is the primary and predominant distress type of cementitiously-bound materials. There are two principal forms of cracking:
- cracking from hydration and drying shrinkage
- fatigue cracking.
Austroads Guide to Pavement Technology Part 2: Pavement Structural Design (AGPT02-24) states:
Unbound granular pavements with sprayed seal surfacings are the major pavement type in rural Australia, comprising some 90% of the length of all surfaced roads.
The use of cemented bases with sprayed seal surfacings is more commonly associated with the rehabilitation treatments of granular pavements than new construction works. With the exception of temporary pavements, this pavement type is seldom used for new works due to significant performance issues associated with shrinkage cracking.
Shrinkage cracking of cemented materials tends to be unavoidable… Cracks which propagate to the pavement surface provide pathways for the infiltration of moisture which can lead to debonding of layer interfaces within the pavement and/or weakening of granular layers and subgrade. The extent and severity of cracking is influenced by factors such as binder type and content, material type, initial moisture content and drying and curing conditions.
Whilst the modulus increases with increased binder content, as the binder content increases so does the potential for drying/shrinkage cracking.
For moderate-to-heavily trafficked roads, the minimum 28-day Unconfined Compressive Strength (UCS) is 2 MPa to ensure a cemented material with less variable fatigue properties. When used in the design of new pavements, such materials are commonly covered by a minimum cover equivalent to 175 mm of asphalt to inhibit cracking of cemented materials reflecting to the surface.
For some lightly-trafficked roads, granular materials stabilised with cementitious binders to a UCS of 1–2 MPa have been used as there has been less concern about fatigue cracking causing detrimental effects on the life of thin bituminous surfacings.
A typical unbound granular pavement base might consist of 450mm of imported crushed rock, whereas a cementitiously bound base can utilise the insitu material and achieve comparable fatigue life at half that thickness. Cementitious stabilisation is also much faster, partly because it eliminates the need to move massive quantities of quarry materials. Intuitively, a pavement that is half the thickness and constructed quickly from insitu materials will cost much less to build. However, the technical risks (cracking) need to be managed.
Renolith nanotechnology enhances the performance, and overcomes the key limitations, of cementitiously bound material. It:
- Greatly reduces drying/shrinkage cracking, even at high cementitious binder content
- Increases the range of viable materials to be bound (MTTB)
- Improves the engineering properties of the bound material (compressive strength, flexural strength, elastic modulus, resilience, water resistance)
- Greatly improves the fatigue life of the bound layer
These advantages mean that cementitious stabilisation is viable in cases where it otherwise may not be. For example, a 200-250mm Renolith-enhanced heavily bound (UCS>3MPa) base with thin bituminous wearing course is a very cost effective and well proven design suitable for heavily trafficked roads.
Lifecycle costs
Modelling of lifecycle costs is beyond the scope of this article. However, Renolith nanotechnology provides an excellent opportunity to minimise lifecycle costs according to the following principles:
- Renolith improves the flexural strength and elastic modulus of cementitiously bound material. For a given design (base thickness, binder spread rate, material to be bound), this can yield an enormous increase in the fatigue life of the bound layer compared to cement-only stabilisation. This makes it very easy and low-cost to design for longer life and heavier traffic. (See ‘Renolith 2.0 Design Guide’ via https://renolith.com.au/resources)
- Renolith significantly improves the resilience of bound materials. It may be used in permanently wet applications. This feature greatly reduces the risk of degradation and premature failures from events such as flooding.
Conclusion
Cementitious stabilisation is an inherently low-cost approach to road construction but has technical limitations. Renolith nanotechnology reduces the cracking risks and enhances the engineering properties of cementitiously stabilised materials, which provides multiple benefits such as improved resilience and sustainability. The direct economic benefits are reduced construction costs and reduced lifecycle costs. Construction cost savings of between 15% and 60% have been reported by various independent parties. In a typical scenario such as the construction or rehabilitation of a rural sealed pavement, constructing the base from Renolith-enhanced cementitiously-bound insitu material is expected to result in a cost saving in the order of 40%-50% compared to an unbound granular base design.