Nanomaterials in Road Pavement Construction

1. Introduction

Nanotechnology has recently emerged as a promising field in the construction industry, offering significant improvements in the quality and durability of infrastructure. At the atomic and molecular levels, advancements in material manipulation have made nanotechnology a novel approach to enhancing construction materials, particularly in road pavement applications. Therefore, nanomaterials have been identified as remarkable constituents in construction that provide superior characteristics than conventional materials. These materials make them very appealing in construction as they are normally in the nano scale range with exceptional mechanical, chemical and physical properties. Among these innovations, nano silica and nano clay have proven effective as interlayers, improving the mechanical properties and durability of asphalt mixtures. These materials address longstanding challenges in road construction, such as cracking, rutting, and moisture damage, which are exacerbated by heavy traffic loads and varying environmental conditions. Emerging research indicates that incorporating nanomaterials in road construction enhances pavement resilience, reduces maintenance needs, lowers long-term costs, and minimizes environmental impact. [1,2].

Nanomaterials integration into pavement engineering is pursued to overcome key challenges associated with conventional construction materials. In research it has been shown that the addition of nanoparticles to asphalt mixtures can improve Marshall stability, flow, and rutting resistance. In particular, nano silica has been found to provide asphalt flexibility and durability enhancement by improving bond between bitumen binders and aggregates [3]. This is in line with the fact that nano clay increases stiffness and load bearing capacity of the bitumen binders and asphalt mixtures with resistance against water and temperature induced deformation [4]. Extension of service life of pavements in regions with high traffic volumes and extremes weather conditions is dependent on these modifications [5]. More sustainable infrastructure might be built with the help of nanotechnology in this field in the construction of roads that can survive better environmental stressors and high stress usage.

This review paper was planned as a primary motivation to develop sustainable solutions for road construction which compromise economic, environmental, and performance aspects. The road pavements, as is the case with most traditional road pavements, are prone to deterioration caused by environmental factors, such as moisture, temperature fluctuations and mechanical stresses by traffic loads. Proposed strategy to overcome these are by improving the material properties of pavements and reducing maintenance and its related cost [6,7] is by integrating nano silica and nano clay in asphalt mixtures. Although the theoretical advantages of nanotechnology applications in road construction are well documented, practical implementations and field validations are still limited. This knowledge gap should be investigated further for practical knowledge of the extent to which the nanomaterials affect pavement engineering.

The benefits and challenges of using nano silica and nano clay in construction materials have recently been illustrated in studies. Nano silica, for example, has demonstrated potential to increase compressive strength and fatigue resistance of concrete and asphalt mixtures. Specifically, this attribute is extremely useful for highly trafficked areas in which strength must be elevated and relative susceptibility to deformation must be minimized [9]. In addition, nano silica's small particle size promotes better compatibility with the asphalt binder resulting in better viscosity and more resistance to rutting and fatigue [10]. In contrast, asphalt has been investigated for modification of its rheological properties using nano clay, with the resultant suspension being resistant to moisture damage and thermal cracking [11]. Unlike ordinary concrete, these nanomaterials have unique properties that can alleviate problems usually experienced in pavement construction, including water infiltration, and formation of thermal degradation.

The environmental implications of the nanomaterials in road construction are also considered in the study. While extensive energy is required to manufacture nanomaterials, their ability to improve pavement life and decrease maintenance frequency may counter initial environmental expenditures over the pavement lifecycle. Yet, Life Cycle Assessment (LCA) analyses indicate that the production of nano silica and nano clay is more energy intensive than production of conventional materials but using these materials for the construction of pavements can result in reduced long term environmental impacts owing to less consumption of resources in maintenance and repair [12]. It fits in with the growing importance of sustainability in civil engineering, as long term resource efficiency and reduction in environmental footprint is becoming the basis for characterizing materials [13].

Adoption of nanotechnology in pavement construction carries with it, however, concerns about the uniformity of nanoparticle dispersion in asphalt and environmental and health risks for nanoparticle production and disposal. On the one hand, laboratory studies have demonstrated repeatedly the benefits of nanomaterials in performance, and on the other, these benefits have not been readily scaled to real world applications. Lack of performance and durability of nanomodified asphalt may occur due to variations in nanoparticle quality, stability, and interaction with the other materials [14]. Furthermore, current regulatory frameworks for nanomaterials in the context of construction are nascent, creating potential risk that is still unexplored. Nanomaterials in road construction should address these challenges, which require interdisciplinary research and collaboration between material science, environmental engineering and regulatory bodies [15].

For this reason, this paper aims to add as a contribution to the knowledge of the uses of nanotechnology in pavement engineering and at the same time, to assess the benefits and challenges of nano silica and nano clay additives in asphalt mixtures. This review paper examines the physical-rheological properties and environmental impacts of nanomaterial modified asphalt focusing on developing insights that will influence future asphalt pavement design and construction to be more durable and sustainable. Ultimately, the findings will help civil engineers apply nanotechnology and support innovations in the development of infrastructure.

2. Background of Nanomaterial in Asphalt Pavement Construction

Nanomaterials are acknowledged as one of the key advancements in the construction industry, especially in pavement engineering, because of the characteristics of materials at the nanoscale. Nanotechnology has enabled scientists to alter materials at nanoscale in a way that results in the production of new materials with superior properties to those of conventional materials. Nanotechnology of pavement construction may be considered a relatively new concept in the modern world because of the stimulation of improved performance, durability, and sustainability of the roadway structures [10,12]. Recently, the incorporation of nanomaterials in pavement construction has been due to high demand for long-lasting, sustainable and economical pavement construction materials. Asphalt and concrete pavements among others are usual on regular construction projects and most of them have some problems associated with cracking, deformation or even environmental deterioration. These problems may well be solvable with nanomaterials, which have better mechanics and act at the molecular level. Nano clay is one of the most used nanomaterials in the construction of pavements. Nano clay is used with the purpose of enhancing the mechanical properties of the asphalt mixtures. It increases the tensile strength, flexural strength, and elongation of asphalt making it less susceptible to deformation and cracking due to traffic loads. Also, nano clay can enhance the low temperature performance of asphalt hence reducing low temperature thermal cracking [13,16].

3. Results of Review and Analysis

3.1. Nano Clay Modified Asphalt Mixes

3.1.1. Physical Properties

Bulk Density

The introduction of nano clay in asphalt mix allows creating only a mean bulk density 0.6433 g/cm³, which is lower than bulk density of conventional asphalt mixes made from traditional asphalt. A lower mass is advantageous for several reasons and can be used particularly when a lighter mix results from a reduced particle size and is advantageous for transport and application procedures due to the reduction in transport costs as well as handling during application. Nano clay bulk density is between 0.61 and 0.67 g/cm³ in a relatively uniform variation [17,18]. This uniformity in density indicates consistency in the physical properties of material, which is favorable when employing the material in pavement development. A consistent bulk density can provide more homogenous asphalt matrix which in turn reduces the number of air voids in the mix. Excessive voids, however, are a common cause of moisture infiltration into the slab, resulting in potholes and cracks, and therefore are critical, especially at lower air void content. Therefore, nano clay’s ability to create a denser packing structure within the asphalt is advantageous to improve the durability and decrease the deformation under the load.

Specific Gravity

The measured average specific gravity of nano clay de-notes the material’s density, comparing it to water. Given its high level of specific gravity, this means a dense material that is well suited to construction applications where compactness and stability are required. The nano clay makes it a dense material, improving the stability and load bearing capacity of the asphalt mix, so that the loads are distributed well across the pavement. It also means it has higher specific gravity (chippier) and it compacts better, resulting in better overall pavement performance. Nano clay particles, when mixed into asphalt increase the ability of the mix to compact, i.e. under pressure, to form a more stable matrix, and an asphalt matrix that resists deformation when subjected to trafficking loads such as repeated traffic loads. The addition of a nano clay that has a very high specific gravity in asphalt improves the durability of the pavement and makes it as resilient to traffic induced stresses, as well as to environmental factors [16,19].

Surface Area

Effectiveness of nano clay in asphalt as a modifier depends on its surface area. Surface area of nano clay varies from 150 to 324 m²/ g with mean of 243.14 m²/g [16]. The large surface area allows for greater contact between the nano clay particles and asphalt binder so that the binder ads on the aggregate in the mix more strongly. That increases adhesion, which is the ability to stick together within the asphalt and that is important for resisting deformation under the potential weight of traffic. This increase in surface area allows the nano clay to make stronger molecular bonds than normal clay, thereby increasing the pavement’s ability to withstand both compressive and tensile stresses. This characteristic also contributes to the resistance to cracking and rutting, especially in areas with very high traffic loading. The overall effect of high surface area of nano clay on the mechanical stability of the asphalt mix is to improve the mechanical stability of binder-aggregate matrix which in turn creates a more durable asphalt pavement structure.

3.1.2. Strength and Physical Properties

Marshall Stability

Nano clay remarkably improves Marshall Stability when used around 5%. At this concentration, the Marshall Stability peaks at about 14.18 kN, indicating that the asphalt mix has better resistance to load induced deformation. The Marshall Stability describes the resistance of an asphalt mix to compressive stress and higher values indicate that loads can be applied to the mix before failure. Nano clay particles can effectively reinforce the asphalt matrix, achieve 5% nano clay concentration in the asphalt mix, and improve asphalt mix’s load bearing capacity. However, stability values decrease slightly beyond this concentration. Excess nano clay can cause particle agglomeration which makes it less effective as a reinforcing agent. It is therefore concluded that optimal nano clay concentration for improving the stability of asphalt mixes such that they are suitable to be used as road pavements exposed to moderate to high traffic volumes, is 5% [18].

Marshall Flow

Nano clay modification of asphalt mixes shows increased flexibility and resistance to deformation than the Marshall Flow values. The Marshall Flow values show a very good improvement and get as close to 2.17 mm at a concentration of 6%. This means that the mixture has exhibited an optimum combination of stiffness and flexibility to combat the permanent deformation, like rutting, which is induced by traffic load. However, Marshall Flow values decrease at higher concentrations such as 9%, indicating increased stiffness, which could crack under stress in environments that range from very high to very low temperature. At 6% concentration, the most optimal flow values for nano clay modified mixes, make it well suited for roads which receive high traffic, and which need a little bit of flexibility, flexi enough to adjust to the traffic loads but not so much that the mix deforms excessively [16,18].

Penetration Test

The impact of nano clay on the flexibility of the asphalt mix is determined from penetration testing. Penetration values then vary with nano clay concentration, reaching a balance around 5-6%. For these levels penetration values stabilize around 68 mm showing a mix that is sufficiently flexible to absorb stress yet stiff enough to resist rutting. In asphalt pavements, this balance is necessary, because over flexibility may cause deformation while over stiffness may result in a brittle and prone to cracking pavement. Extending the lifespan of the pavement at these concentrations also enhance the flexibility and rutting resistance [13].

Softening Point Test

Nano clay improves the thermal stability of asphalt by its softening point test. The softening point stabilizes, and resistance to very high temperatures is increased at concentrations between 5 and 6%. Advantageously, it provides enhanced thermal stability which is useful for pavements in hot climates where the risk of rutting, or other deformation, under elevated temperatures is reduced. It is found that the highest softening point recorded is 54.7°C at 9% nano clay concentration, which could be advantageous for particular high temperature applications while reducing reliability. This means that the concentration range of 5 – 6 % nano clay is optimal balancing thermal stability and flexibility to withstand environmental impact [13,14,15,16].

3.2. Nano Silica Modified Asphalt Mixes

3.2.1. Engineering Properties

Bulk Density

Mean bulk density of the nano silica modified asphalt mixes is 0.1124 g/cm³ which shows the material is lightweight. Reduces pavement weight and all that it entails: transport and handling cost. The density range for nano silica modified mixes studied extends from 0.056 to 0.23 g/cm³, demonstrating that the resulting material is uniformly distributed in the asphalt matrix. This distribution reduces voids in the mix and improves compaction, therefore this distribution will resist moisture intrusion, which in turn reduces the risk of potholes and cracks. By improving compaction and reducing material handling costs, the low bulk density of nano silica and the increased capacity to improve compaction of the dry granular mixture makes nano silica an attractive additive for pavement durability [13,14,15,16,18].

Specific Gravity

Nano silica has a specific gravity of 2.5443, which is on the high side, to stabilize asphalt mixes. The material’s ability to distribute loads across the pavement and prevent load deformations is based on this high specific gravity. High specific gravity materials such as nano silica are ideal for asphalt mixes that require high loads and high traffic pavements to assure stability and load bearing capacity. Nano silica improves the mix’s density and stability, increasing the pavement’s resistance to vehicular loads and increasing its useful life while reducing maintenance needs [16,18].

Surface Area

Surface area of the nano silica ranges from 111 to 690 m²/g (arithmetic mean, 342.23 m²/g). The broad surface area of nano silica enhances the contact between nano silica and the asphalt binder, resulting in higher bonding of nano silica in the mix. For these strong molecular bonds to prevent fatigue and rutting under traffic loads, a high surface area is critical. Nano silica increases the bonding potential of asphalt matrix improving its advantage under both compressive and tensile stresses. Therefore, nano silica’s large surface area makes it a suitable additive for increasing the mechanical properties of asphalt in cracking and deformation resistant applications [18].

3.2.2. Strength and Physical Properties

Marshall Stability

Marshall Stability is improved greatly by nano silica; the greatest increase appears around 4 to 6% concentration with values reaching up to 18.00 kN. Such an order of stability shows that asphalt mixed with nano silica modification be capable of bearing higher loads without deformation and is suitable for roads with heavy traffic. Results show peak stability values of approximately 20.00 kN at 8% concentrating, indicating that nano silica effectively reinforces the asphalt matrix to bear more loads without cracking or rutting. However, the degree of variability in stability at higher concentrations suggests that the mix could become too rigid, losing a degree of flex under load. As a result, nano silica concentrations in the range of 4–6 % are suggested for most load bearing performance with maximum flexibility [13,14,15,16,18].

Marshall Flow

Results of Marshall Flow tests show that nano silica modified mixes have optimal flexibility at concentrations between 2 and 4%. The flow values at this range (about 3.20 mm) indicate that the mix has enough flexibility to withstand permanent deformation from traffic induced stress. Flow values decreased dramatically at weights above 5% indicating a stiff mix, which may have good resistance to rutting but may be susceptible to cracking under stress. For pavements exposed to moderate high traffic loads, the range of concentration is 2% to 4% nano-silica falls within a balance of flexibility and resistance to deformation [13,14,15,16,18].

Penetration Test

Results of penetration values indicate that including nano silica stiffened the asphalt mix and had the greatest impact at 1–3% concentrations. Penetration values at these levels are so small, indicating stiffness so high that pavement would be able to resist deformation. But unlike most metals, this stiffness doesn’t come at the expense of flexibility at moderate concentrations: Roads that see varying temperatures can exist with flexibility. However, as the concentration becomes greater than 4%, they still increase stiffness and continue to reduce risk positively (flexibility), which could lead to brittleness. It is found that for nano silica modified mixes, the optimal penetration range is between 1 and 3# [18]. The penetration properties of bitumen are crucial indicators of its consistency and resistance to deformation. The incorporation of nano silica significantly alters these properties by reducing penetration values, leading to a stiffer and more durable binder. This reduction occurs because nano silica particles enhance the internal structure of bitumen, improving its cohesion and resistance to temperature-induced softening. Studies have shown that bitumen modified with nano silica exhibits lower penetration values compared to conventional bitumen, indicating improved resistance to rutting and permanent deformation. These enhancements make nano silica a promising additive for producing high-performance asphalt pavements with extended service life [12].

Softening Point Test

Results of the softening point indicate that nano silica enhances the thermal stability of asphalt mixes, with the greatest increase at concentration range between 0.5% to 3%. The softening points peak at 65°C showing that the nano silica modified mix can tolerate high temperatures without softening. The thermal resistance in this case is important for asphalt used in hot climates, to prevent rutting. But high concentrations of above 4% may cause excessive stiffness and the mix will tend to crack more prone under natural thermal expansion and contraction. Thus, a nano-silica concentration range of 0.5- 3 % is an optimal one in terms of maintaining thermal resistance as well as flexibility [13,14,15,16,18].

4. Discussion

4.1. Interpretation of Nano Clay Results

The results show that nano clay improves mechanical properties of asphalt, with maximum Marshall Stability and load bearing capacity at 5% concentration. When compared to studies that find clay reinforcement of the asphalt matrix enabling it to withstand compressive stress without significant deformation, this outcome agrees. Earlier research by Shafabakhsh et al. (2023) postulated that nano clay contributes structural integrity by forming a dense network within the asphalt matrix and consequently reduces air voids and improves durability and this improvement in Marshall Stability at optimal concentration concurrences [19].

Additionally, Marshall Flow values between 6% nano clay concentration exhibit balance between flexibility and stiffness to decrease the likelihood of rutting while facilitating the ability of the pavement to respond to thermal stresses. Although previous research suggested that nano clay increases asphalt flexibility by increasing binder viscosity to prevent fatigue cracking, in colder climates, the binder tends to be more brittle and thus more prone to cracking [20]. Nano clay modified mixes also soften at 5-6% and provide additional resistance to heat deformation. These findings are comparable to what Hanus and Harris found (2013), who found thermal resistance increased in asphalt containing nano clay because it has a dense molecular structure that is less susceptible to thermal cracking [21].

The results also show the advantages from using nano clay in road pavement applications simultaneously requiring flexibility and strength. Nano clay sponge at an optimal 5-6% concentration can alleviate thermal expansion and contraction problems in regions with fluctuating temperatures, keeping the pavement alive slightly longer. Nano clay being light weight also improves the asphalt density and thereby transport cost and emission that fits in with sustainable construction goals.

4.2. Interpretation of Nano Silica Results

Marshall Stability and flow are shown to dramatically improve for nano silica at a concentration range of 4 to 6%. And at these levels the nano silica enhances stiffness and the load bearing capacity as seen from the peak stability values approaching 20.00 kN. The reinforcement owed to nano silica high surface area that increases binder adhesion to aggregates to produce a stronger more durable matrix. Okem et al. (2024) studies are supportive to this effect, in which the nano silica improved the tensile strength and rutting resistance of the modified asphalt mixes [22].

Nano silica modified mixes were found to have an optimal balance of flexibility at 2-4%, consistent with the hypothesis that nano silica increases the binder’s stiffness without decreasing its flexibility. The finding here echoes the work of Lushinga et al. (2022) who found reduced rutting and increased resiliency in nano silica infused asphalt mixes due to high specific gravity and surface area [23]. These, along with the penetration and softening point values, indicate that nano silica offers thermal resistance at optimum levels for high temperature climates. Moreover, further studies confirmed that nano Silica modified asphalt has resistance to deformation under thermal stress and improves its suitability for regions with extreme temperatures [22,24].

Widely used in road construction, nano silica opens a promising remedy for heavily trafficked roads requiring both thermal stability and durability. Compared to nano silica, other modulators suffer from low specific gravity and high surface area failing to improve the resilience of pavement under high stress conditions. Nano silica inclusion in asphalt can reduce rutting and maintenance needs, resulting in lower life cycle costs and environmental footprint of road infrastructure from an environmental perspective. Additionally, we demonstrate that improved performance can be obtained for concentration values between 4 to 6% without significant increases in material costs [25,26]. In addition. both nanomaterials and waste materials (like waste plastic and fiber) have shown significant potential in enhancing asphalt performance by improving mechanical properties, durability, and sustainability. Nanomaterials, such as nano silica and nano clay, refine the microstructure of asphalt, increasing stiffness, resistance to rutting, and overall durability. Similarly, waste materials like recycled rubber, plastic, and industrial by-products (e.g., fly ash and slag) contribute to reinforcing asphalt by modifying its viscoelastic properties and improving resistance to fatigue and moisture damage [5,10,27,28,29,30].

4.3. The identification of ideal percentage of nanomaterial for the construction of road pavement

4.3.1. Nano clay modified asphalt mix percentage.

An optimal quantity of nano clay (approx. 3%) is applied to asphalt throughout analysis of road pavement using nano clay for improvement of mechanical properties. For road pavement applications, a combination of several key factors such as better Marshall Stability, reasonable Marshall Flow, and improved resistance to penetration represents better performance at this concentration.

• Marshall Stability: It also shows improved Marshall Stability at 3% nano clay. It is a value that is a function of asphalt mix ability to be deformed under load, a property important to asphalt mix durability, in high traffic area. Above this level the clay content has diminishing returns as higher constituents work against the workability of the mix and its compaction.
• Marshall Flow: The asphalt is retained to have a flow value of about 3% nano clay, sufficiently soft so the pavement is not susceptible to rutting or does not otherwise have the other deformation capacity to accommodate environmental stresses such as temperature variations.
• Penetration and softening point: Again, the trend in terms of penetration shows that the optimal balance between stiffness and flexibility is obtained with nano clay at 3%, while the binder can be less susceptible to deform under heavy loads, but less rigid. These results suggest that 3% nano clay gives the best compromise between mechanical performance and environmental sustainability. As the construction material for road pavement in the Australian environment, the increased flexibility and durability of the asphalt mixture at the expense of some cost and environmental impacts, is an ideal choice.

4.3.2. Optimal content of nano clay modified asphalt mixes

Nano silica has a strong advantage in asphalt mix compared with other nano materials, since it’s better performance in aging of binder according to the research investigation. Compared to these concentrations, mechanical improvements from nano silica modified mixes in asphalt are substantial without compromising environmental sustainability.

• Marshall Stability: Marshall Stability values peak at 3% and 4% nano silica. It suggests a significant rise in the load bearing capacity of asphalt mix to withstand deformation under heavy traffic. At 3%, the mix provides good strength and workability compromise.
• Marshall Flow: The asphalt mix would have sufficient flexibility to prevent premature cracking, without adversely affecting the asphalt’s ability to resist permanent deformation, and consequently sustain long term pavement integrity, 3% by volume nano silica Marshall Flow values.
• Penetration: With penetration values still stiffer at 3% nano silica than with conventional high silica 25% coverage, these properties are necessary if the flexibility of Australian roads is to be minimized while also reducing softening and deformation in high temperature conditions.

While the nano silica concentration for road pavement construction is in the order of 3%, nano clay concentration for the same purpose is like 3%. It results in improved mechanics of asphalt mix, with reduced environmental impact. The use of 3% nano silica increases load capacity, resistance to deformation and durability, and therefore its use for long lasting, environmentally sound roads is now realistic.

5. Conclusions

The research reported in this progress report is from a broader study of the use of nanomaterials in road pavement construction, namely nano clay and nano silica. Using the research, there are such key findings that show tremendous improvements in physical and rheological properties of asphalt mixes with addition of nanomaterials. They also address critical problems in road construction (durability, load bearing capacity, resistance to deformation, environmental impacts) and can be applied to modular systems in temporary construction and maintenance.

5.1. Nano Clay

Optimal Concentration: The results show that about 3% is the optimal nano clay concentration. The mechanical improvement of asphalt is outweighed by the negative environmental impacts which are squeezed between bursts of concentration. The environmental burdens increase once above, and the returns on related when we take increasingly, and increasingly, from the environment.

Improved Marshall Stability: Pavement strength under high traffic loading improved as shown by test results in terms of Marshall Stability at 3% nano clay content, implying greater resistance against deformation. However, in high traffic areas, extending the longevity of pavements depends on the stability of the soil.

Marshall Flow and Penetration: At the concentration of 3%, a stable Marshall Flow is required to ensure balance between stiffness and flexibility in the asphalt. It gives assurance that the pavement can withstand mechanical stress as well as variations such as temperature, which will not crack. At this concentration it is found in penetration tests that the asphalt mix resists permanent deformation although it is not excessively rigid.

5.2. Nano Silica

Optimal Concentration: Nano silica has an ideal concentration between 3 and 4%. The up range is represented by a balance between mechanical performance and environmental sustainability.

Enhanced Mechanical Properties: Maximum Marshall Stability is 3–4% nano silica, with tremendous increase in load bearing capacity. The mechanism also improves the asphalt's resistance to deformation due to traffic loads. When this is concentration, the Marshall Flow data indicates that there is sufficient pavement flexibility to avoid cracking, but enough strength to avoid permanent deformation.

Temperature Resistance: The penetration and softening point tests demonstrate that nano silica increases the mix’s resistance to high temperatures, an important characteristic for pavements found in Australia’s very hot climates. It is stiff enough to resist rutting but has sufficient capacity to tolerate traffic induced stress.

5.3. Performance Evaluation

Details of performance for asphalt mixes when modified with nano clay and nano silica were investigated. Results from these nanomaterials showed that both mechanical and thermal properties of the asphalt were improved, which led to stronger, more durable pavements. These materials also improved Marshall Flow and penetration values to indicate the asphalt’s ability to flex before cracking without cracking.

5.4. Long-Term Durability

Long term durability improvement is proposed using road pavements containing recommended concentrations of nano clay and nano silica paved. By improving the mechanical properties of asphalt, these nanomaterials extend pavement life and lower the rate of maintenance and repair costs. For high traffic loaded and extreme environmental conditions, such savings can be substantial for infrastructure projects.

The research findings suggest that nano clay and nano silica can indeed revolutionize the construction of the road pavement. Improved durability, strength and environmental performance of modern infrastructure projects is provided by their incorporation into asphalt mixes. Both materials achieve a good compromise between mechanical benefits and environmental sustainability at concentrations around 3%. However, the research indicates that even with optimal concentrations of the nanomaterials in the transport, higher levels of the nanomaterials in situ could have negative environmental impacts.

Long term performance testing, field trials and a more detailed environmental analysis of nanomaterial included in an asphalt are required along with other aspects of the currents research. Finally, for Road Construction applications, the process of producing and mixing nanomaterials could be optimized for nanomaterial performance and sustainability.

The integration of nano clay and nano silica nanomaterials is the promising avenue to developing more durable and resilient environmentally friendly road pavements. Therefore, these materials could play a vital role in future construction of roads to assess the balance between strengthening properties that improve mechanical performance, but which also help to enhance the road's environmental responsibility.