Constructability of road pavement layers using New-age (PDF)

Article Constructability of road pavement layers using New-age (Nano) Modified Emulsion (NME) stabilisation of naturally available granular materials in roads varying from highways to local ac- cess roads Gerrit J Jordaan 1,2,* and Wynand J vdM Steyn 3 1 Department of Civil Engineering, University of Pretoria, Pretoria 0002, South Africa 2 Jordaan Professional Services (Pty) Ltd., Pretoria 0062, South Africa 3 School of Engineering and Department of Civil Engineering, University of Pretoria, Pretoria 0002, South Africa; [email protected] * Correspondence: [email protected]; Tel.: +27-(0)-824164945 Featured Application: The general use of New-age (Nano) Modified Emulsion (NME) is appli- cable for the construction of high-order multi-lane highways to lower-order access roads in vil- lages/townships. These nanotechnology solutions are suitable for use with construction equipment ranging from the most sophisticated to the elementary, including labour-enhanced construction methods. NME enhancement/stabilisation of materials for use in roads enable the use of marginal material in all categories of roads. The general acceptance of these new disrup- tive technologies will be driven by the ease of use, time and cost implications and robustness of the technology during construction in practice, with associated reduction in risks and costs. Abstract: The introduction of any new disruptive technology in a traditionally well-established industry, such as the road construction industry, is usually associated with considerable resistance. This is especially relevant when the new technology is based on the use of granular materials tra- ditionally considered to be of an unacceptable quality in combination with relatively new concepts such as New-age (Nano) Modified Emulsions (NME). In such cases, the fact that the material de- sign methods are based on fundamental scientific principles and have been proven in laboratories and through Accelerated Pavement Testing (APT), may be of little influence. However, the general acceptance of new disruptive technologies, e.g. telecommunications and Information Technologies (IT), have been based on the considerable advantages it presented. The same principles are appli- cable to the general acceptance and use of NME stabilisation/enhancement of materials in the road construction industry. This article is aimed at the practical demonstration of the advantages of the use of nanotechnologies in the construction of the highest order roads (i.e. inter-city multi-lane highways) to lower order access roads (i.e. Low-Volume-Roads (LVR) and even local accesses to farms and in villages/townships). The implementation of NME technologies is directly associated with ease of use, time and cost savings and the addressing and reduction of risks. Keywords: Constructability using nanotechnology applications, nano-silane stabilisation of gran- ular materials, highway construction, central plant mixing; recycling, rehabilitation using nano-silane technologies, materials compatibility, nanotechnology construction related problems, maintenance advantages of nanotechnology solutions 1. Introduction The introduction of any new disruptive technology [1] in a traditionally well-established industry such as the road construction industry, is usually associated with considerable resistance. This is especially relevant when the new technology is based on the use of granular materials traditionally considered to be of unacceptable Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1 © 2021 by the author(s). Distributed under a Creative Commons CC BY license.  quality in combination with new relatively new concepts such as New-age (Nano) Mod- ified Emulsions (NME). In combination with fundamental concepts in terms of practical pavement engineering, such as Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS), to evaluate the suitability of the use of stabilised granular materi- als in road pavement layers, nanotechnology advantages may be met with resistance in practice by traditionalists unfamiliar with these material evaluation techniques. In such cases, the fact that the stabilised granular material design method is based on funda- mental scientific principles [2,3,4,5,6,7,8], been evaluated and proven in National Re- search and University laboratories [4,9,10], evaluated in practice through Accelerated Pavement Testing (APT) [11,12,13] and implemented on several roads in southern Africa [14] may have little effect on the construction industry. In order to be of benefit and to assist in addressing the considerable backlog in transportation infrastructure in (especially) the developing regions of the world, the practical aspects associated with new technologies must be proven to such a degree that all doubts are sufficiently addressed in order to overcome a natural resistance to change. A good transportation infrastructure network forms the backbone and is a pre-requisite to economic development of any country. Hence any potential considerable savings in the unit costs for the provision and maintenance of road infrastructure (without com- promising quality and durability), need to be adopted without delay. This can be ac- complished through pre-empting any construction related concerns and addressing po- tential problems and risks for general acceptance to be achieved. Accelerated acceptance of the introduction of new disruptive technologies, such as in the telecommunications industry (cell/mobile phones) and Information Technologies (IT) (computer technologies), have been based on the considerable advantages these technologies presented to the general population. The same principles are applicable to the general acceptance and successful use of NME stabilisation/enhancement of granular materials in the road construction industry. Proven benefits and risk reductions to the road construction industry will lead to the adoption of nanotechnology solutions despite traditional resistance to change. This article is aimed at the demonstration of the ease of use and the practical advantages of the implementation of NME stabilisation of naturally available granular materials. The applicability of these technologies is demonstrated for the construction of the highest order roads (i.e. inter-city multi-lane highways) to lower order access roads (i.e. Low-Volume-Roads (LVR)) and even local accesses to farms and in villages/townships. No technology is without risks. However, a rigorous process of risk assessment and the development of a scientifically based material design method [8], laboratory evalua- tions [4,9,10] and full-sale APT loading assessments [11,12,13], allowed for design risks to be identified and as far as possible, to be addressed in practice. However, contractors often experience unforeseen risks, many of which can be prevented or limited through the timeous identification thereof and the demonstration of the consequences and possi- ble solutions to construction problems through practical examples. Over and above construction procedures, this article also identifies and addresses some of these more subtle (but logical) construction problems that can easily be prevented by following sound construction practices. NME stabilising agents are highly “forgiving” even in cases where engineering cri- teria are initially not met due to unforeseen circumstances (e.g. weather conditions or construction equipment problems). In such cases, remedial actions are often possible without major cost implications. These corrective actions are usually associated with a better understanding of the impact and interaction of the NME technology on the gran- ular materials and the basic engineering properties to be achieved in terms of UCS, ITS and durability (Retained UCS (TCS) and Retained ITS (RTS) criteria. Basic principles to construction practices forms the basis for the successful implementation of any technol- ogy/procedures and, in some instances, NME stabilising agents may expose unsound practices. Cost-effective solutions to possible construction related problems are crucial to be understood as a function of the inherent characteristics of the NME stabilising agents. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  Nanotechnology solutions can, in line with the construction and rehabilitation of roads, also contribute significantly to the cost-effective maintenance of the existing surfaced road networks, providing water-resistant solutions while creating numerous employ- ment opportunities through improved maintenance (routine as well as periodic) actions of a valuable national asset. 2. Construction Industry Acceptance of New Technologies The introduction and general acceptance of any new technology in an established industry are a function of a number of factors, including: Primary construction related interest factors influencing new technology introduc- tion: • Influence on profitability; • Required equipment and cost thereof; • Ease of construction; • Production rates to be achieved; • Delays caused by slow drying/setting of materials; • Risk associated with implementation; • Actions required to reduce risks; • New skill-set requirements for practical implementation; • Industry resistance to change as a function of comfort with design approaches and vested interests, and • Perceived treads to established monopolies. Secondary interest factors: • Toxicology (normally addressed through legal requirements), • Environmental factors (normally addressed by legislation), and • Addressing the unknown – the fear-factor, by demonstrating safety, opportunities, benefits and addressing scepticism among traditionalists. Most of these primary and secondary factors have already been discussed in detail in the various publications referred to [2,3,4,5,6,7,8]. The practical construction issues, e.g. the use of equipment, identification of and solutions to potential problems and the ad- dressing of opportunities, e.g. maintenance advantages presented through the imple- mentation of nanotechnology solutions, are addressed in this article. The versatility and ability of anionic NME stabilisation/enhancement of granular materials to address needs at all levels of the road construction industry are of prime importance. It enables the fiscus and authorities to provide more infrastructure at con- siderably reduced costs without compromising engineering quality. As demonstrated in this article, the implementation of NME technologies will reduce risks to contractors (ease of implementation/operations, generating of opportunities for entering the market space, generation of more projects with the same available funds) and create opportuni- ties to maintain or increase profitability. 3. Defining Marginal Materials The use of marginal materials in road pavement design and construction is usually associated with Low Volume Roads (LVR). This general perception among pavement engineers in terms of the optimum utilisation of granular materials, require a mind-shift in traditional perceptions with the introduction with applicable, proven nanotechnolo- gies. With the enhancement, protection and stabilisation of granular materials using proven nanotechnology applications (organofunctional silane technologies), the tradi- tional perception of marginal or unsuitable granular materials for use in specific pave- ment layers as a function of design criteria, is far from accurate. It is by far more easy to adjust and enhance the material properties of a relatively good quality granular material (just not meeting the standards of freshly crushed stone), compared to the enhance- ment/improvement of the quality of very poor-quality materials, containing high per- centages of secondary minerals. The definition of “marginal” materials and the use Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  thereof in various road categories is discussed using the basic, easily comparable, relative qualities of the South African granular material classification system [15] as summarised Figure 1. For a full understanding of the granular material classification system as well as scientific basis of the nanotechnology solutions, the various references should be studied. Figure 1: Summary of the comparative relative qualities of granular materials as defined using the South African road building material classification system [15] (definition of Mod AASHTO refer [16,17]) – prices associated with the various materials vary depending on the availability from region to region and are based on material costs in South Africa (2021- excluding haulage costs) – depending on the scarcity of high-quality granular materials these prices may vary considerably The traditional material classification system presented in Figure1 [15] and the use thereof in practice, is, off-cause a function of the design traffic loading, usually expressed in terms of the Equivalent number of dual wheel 80 kN single axle loads [16] (E80s) cal- culated over the design period [17]. The design E80s are closely associated with the Cat- egory of the Road, the expected Level Of Service (LOS) and the number of vehicles (ca- pacity) of the road as per normal new road or rehabilitation design. The Category of road will also determine the accuracy of design [e,g.8,18,19] as well as the required structural and functional characteristics which must be addressed through the application of nor- mal accepted guideline documents developed and used throughout the world in various countries. As an introduction to and the understanding of the relevance of the construction techniques, the comparative design catalogue (design pavement structures for design traffic loadings of 1 million standard dual wheel axle loadings (E80s) to 30 million E80s) and the material requirements are repeated in Figures 2 [8], 3 [8] and 4 [19]. It should be noted that the application of the NME technology is not limited to 30 million E80s. The APT results (tests performed by the South African CSIR [11,12]) have demonstrated that designs can, with ease, be done for traffic loadings to at least a 100 million E80s. The de- sign of LVR and access roads have also been addressed in more detail in a comprehensive design document applicable to all environmental Climatic Zones of the World [19] with applicable materials criteria summarized in Figure 4 [19]. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  From the comparative design catalogue (Figure 2), it is seen that for the higher order roads, using conventional designs, a high-quality crushed stone is prescribed for the construction of the base layer (as an alternative to full-depth asphalt designs). This ma- terials are usually only available from commercial sources at a considered cost which, in addition, is also associated with haulage costs that could be substantial, depending on the availability of the material relative to the distance from the construction site. Haulage costs may be a major factor in areas between the Tropics close to the Equator and in de- sert areas where sources of high-quality crushed stone may be a scarce commodity. In comparison, naturally available materials (gravels of a G5 to G8 quality (refer Figure 1) or sand of various gradings), may be more readability available close to construction sites. The use of the naturally available granular materials together with a material compatible anionic NME stabilising agent, may result in considerable savings in material costs as a basic input into life-cycle cost analyses [18]. Naturally available materials close to, but not meeting the classification crite- ria/properties of freshly crushed stone, usually still contain a solid core of primary min- erals with some presence (relatively small percentages) of secondary minerals which developed as a result of some chemical weathering. The neutralisation of any possible negative effect of these secondary minerals, using applicable nanotechnologies, are rela- tively easy to achieve by following the recommended materials design method [8]. The opposite is the case with materials of very poor quality as defined for use in road pavement structures (these materials may be classified as very good for purposes such as agriculture). In these cases, the bulk of the naturally available material may con- sist of secondary minerals with the structure of the particles of the primary minerals al- ready compromised due to the process of chemical weathering [8]. It follows that the crushing strength of the primary minerals present in the naturally available may already have been compromised. Although more complicated, the characteristics of these mate- rials can also substantially be improved using applicable nanotechnologies [8]. In these cases the material may be improved for use in the upper layers (base and/or sub-base of LVR or even roads with design traffic loading up the 3 million E80s, or the supporting layers of pavement structures with higher design traffic loadings. In terms of traditional designs, G3 to G6 materials are considered marginal or un- acceptable for use in roads with a design loading in excess of 10 million E80s. However, in combination with a material compatible anionic NME stabilisation agent, this quality of material is chemically improved to be suitable for use in the base and sub-base layers of these roads. Depending on the mineralogy of the materials and the implementation of a scientifically based materials design approach [8], a material compatible anionic NME stabilising agent can be used with confidence with G3 to G6 materials to meet all engi- neering specifications for design traffic loadings in excess of 10 million E80s, without compromising quality. In fact, the material compatible anionic NME stabilising agent will protect every particle of the granular material used in the construction of the pave- ment layers from access to moisture (water) and prevent any possible weathering during the design period of the road [8]. Hence, long term durability is improved with an asso- ciated reduction in future periodic maintenance requirements. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  Figure 2. [8]: Comparative pavement designs based on high-quality crushed stone and/or cement-treated materials with relatively thin surfacings and the newly recommended NME stabilised designs using naturally available materials. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  Figure 3 [8]: Minimum recommended standard specifications for New-age (Nano) Modified (NME) stabilised materi- als, addressing four different classifications in terms of engineering requirements. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  Figure 4 [19]: Minimum recommended standard specifications for New-age (Nano) Modified (NME) stabilised mate- rials, addressing Low Volume Roads (LVR) and access roads to remote communities and in villages/townships Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  4. Basic NME Requirements Meeting the Needs of Constructability in often Difficult Conditions Construction operations, especially in the developing regions of the world, often present contractors with severe challenges in terms of various factors unfamiliar to the developing world, including: • Logistical problems getting materials timeously on site due to infrastructure and cli- matic conditions and limited production facilities; • Maintenance problems with regard to construction equipment (limited access to spare parts); • Uncertainties with regard to sureties and irregular payments; • Community factors as a result of high unemployment rates and factional (political) influences and related delays due to often unrealistic expectations of employment created in areas with high needs and poverty, etc. Al of these challenging conditions require that a basic requirement of any product delivered for stabilisation/enhancement of naturally available granular materials must be resilient in nature in these areas. Suppliers need to guarantee the stability of any NME stabilising agent for lengthy periods of time under extreme climatic conditions, often with minimum ability of regular maintenance of the stabilising agent (e.g. circulation of the stabilising agent stored in flow-bins or tankers in the sun under challenging condi- tions). These requirements should be addressed clearly in special provisions within con- tracts, requiring contractors and their suppliers to guarantee the stability of the NME stabilising agent over a period of time (minimum recommended storage time of 4 months), as dictated by local conditions. Any specified stabilising agent must be able to be applied at ambient temperatures without prior heating and circulation and mixed with the construction water with ease to enable quick and reliant distribution and mixing. Product manufacturing must ensure that particle sizes are minimized to ensure that distribution with construction water can be maintained with a minimum risks of blockages to ensure that nozzles of equipment are staying open (provided equipment is clean at the start of operations) during applica- tions. These requirements will prevent frequent delays caused by blockages which will require frequent cleaning operations, resulting in unnecessary stoppages during con- struction. Practical experience in southern Africa has shown that high-quality anionic NME stabilising agents are able to meet these conditions with ease. 5. Construction of NME stabilised pavement layers in practice – basic requirements 5.1. Weather conditions Weather conditions and limitations to construction as per normal road construction projects are applicable of the construction of road pavement layers using NME stabilising agents. The NME stabilising agents must be added to the construction water prior to the addition thereof to the granular materials that are being stabilised. The in-situ moisture of the materials will determine the total construction water required (together with the stabilising agent), in order to achieve optimum construction compaction conditions. Ex- perience has shown that the best conditions are normally achieved at moisture contents just below Optimum Moisture Contents (OMC). Hence, it is recommended that the total of the added fluid content of the NME stabilising agent be taken into account in the cal- culation of the required construction water to be added. For example, if the OMC of the granular material to be stabilised is 8 per cent and the granular material to be stabilised contains 5 per cent moisture, the construction water with the NME stabilising agent to be added is (8 – 5) 3 per cent. In the case where the optimum NME stabilising agent has been established through laboratory testing to be 1 per cent. The 1 per cent NME stabilising agent need to be added to 2 ( 3-1) per cent con- struction water prior to the mixing with and stabilising of the granular materials. Some modern recycling equipment allows more than one feed into the recycler. Under no cir- Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  cumstances should the NME stabilising agent and construction water be fed into such equipment separately. Water in the carrier of the NME stabilising agent and the separate addition of water and the stabilising agent will not allow for the distribution of the NME stabilising agent with the construction water and result into an unsuccessful stabilisation of the pavement layer. Depending on local conditions (e.g. very hot days), allowance should be made for the evaporation of water during the stabilising process by increasing the percentage of construction water. The increase of the construction water will also depend on the type of equipment used in the stabilisation process (which will influence the construction time and hence, result in an increase in the evaporation of the water). 5.2. Delivery and storage of NME stabilising agent to a road construction site The NME stabilising agent is normally delivered to site in 1 000 litre flow-bins (Figure 5) or using bulk storage tankers varying in size from 15 000 to 30 000 litres (Figure 6). Although it is often stipulated by supplier to store flow-bins or tankers in shade, ex- perience has shown that high-quantity anionic NME stabilising agents will be stabile with no separation for more than 4 months (recommended minimum required specifi- cation) in harsh climatic conditions with daily temperatures exceeding 35°C with no shading (Figure 7). In big tankers fitted with a simple circulating pump, a high-quality anionic stabilising agent has been shown to stay stable with no increase in viscosity for periods exceeding 12 months with a once-a-week maintenance (circulation using the fit- ted circulation pump). Figure 5: Arriving on site of material compatible anionic NME stabilising agents on site in 1000 litre flow-bins Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  Figure 6: NME stabilising agents delivered to site in bulk storage tankers varying in size normally from 15 000 to 30 000 litres, depending on the preparation of the contractor Figure 7: Flow bins containing a high-quality anionic NME stabilising agent exposed to high daily temperature conditions showing no separation or an increase in measured viscosity for periods exceeding 4 months 5.3. Clean equipment Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  A pre-requisite to the successful application of a NME stabilising agent is the use of thoroughly cleaned equipment. Although contractors are made aware of this aspect, it is almost without exception found that the first day of operation present problems with the use of equipment containing residue from previous operations. The organofunctional silane modification to a stabilising agent is a re-active agent that will react with any res- idue left in water-bowsers, etc. from previous operations. It has become the norm to expect reactions (as shown in Figure 8) questioning the quality of the stabilising agent when the NME stabilising agent is added to uncleaned wate-bowsers resulting in the formation of blobs sticky threads that are unusual. In order to prevent such fist day oc- currences it is recommended that equipment be inspected before being used on site for NME stabilisation purposes. Figures 9 (a and b) show some results of pre-inspections done on “clean” equipment. Figure 8: Typical example of an anionic NME stabilising agent that has been added to the construction water bowser containing residue from previous operations Figure 9: Typical examples of residue and state of equipment found during the pre-inspection of “clean” equipment dedicated by contractors for use for the stabilisation of granular materials using an anionic NME stabilising agent [] 6. Construction Options using NME Stabilising Agents with Granular Materials Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  6.1. General The construction of highways, rehabilitation of existing roads or the upgrading of rural gravel roads using in-situ materials stabilised with an anionic NME stabilising agent, lends itself towards the utilisation of a full complement of construction methods. Depending on the specific requirements (over and above the designed material end-product specifications) and needs of the Implementing Agency or the Funding Agency, the pavement structure and surfacing can be done using fully, high-accuracy, mechanised equipment or recyclers or conventional equipment or construction proce- dures aimed at the maximisation of labour-enhanced construction methods together will suitable compaction equipment. When requiring labour-intensive construction opera- tions, a mixture of suitable equipment with a high labour content together with specific appliable design options (e.g. type of surfacing) usually proves to be the most cost-effective. These requirements are usually a function of external requirements [18]. The applicable construction specifications would have been preceded by a design procedure addressing the technical and non-technical requirements of any specific road [e.g. 18,19] which may or may not influence the construction process to eb adopted. De- pending on these needs, a life-cycle cost comparison of applicable options [18] will enable the designer to recommend the most cost-effective applicable option, to compile a pro- ject-specific Terms of Reference (TOR) and Bill Of Quantities (BOQ) and project-specific special provisions. These documents are used by contractors to determine the most cost-effective equipment to utilise and submit tenders based on the requirements of any specific contract. With high rates of unemployment in developing countries being a major factor, ex- ternal influences often require bulk infrastructure programmes to address projects with the emphasis on the provision of opportunities for employment and the creation of small enterprises. In such cases, it is recommended that the Implementing Agency adjust poli- cies in order to sign separate session agreements with material suppliers and equipment rental agencies for direct payment by the Implementing Agency. The BOQ should be adjusted to require emerging contractors to price works based on the execution of the works only. Tenders for material suppliers should be based on end-product specifica- tions, requiring suppliers to meet specified minimum requirements in terms of stability of stabilising agents and meeting minimum engineering criteria, for materials as sup- plied. Allowance should be made for suppliers to have access to materials to design and optimise material compatible stabilising agents [8,19]. In the case of labour enhanced construction methods, adequate provision should be included for experienced supervi- sion of the works, with personnel able to accommodate technology transfer as part of their duties. Construction equipment suitable for the construction of NME stabilised granular material pavement layers are discussed starting from the use of the most sophisticated equipment. The practical implementation of these construction practical aspects of the use of various types of equipment are shown with some discussions with regard to the advantages and disadvantages. Discussions are done in the following sequence: • Central plant mixing and construction of base to high levels of accuracy; • Use of recyclers; • Using freely available basic conventional equipment (i.e. water -bowser and grader mixing); • Upgrading of gravel roads using basic equipment, and • Labour-intensive surfacings. 6.2 Central plant mixing and construction of pavement layers using paving equipment As discussed previously, the use of marginal materials and stabilisa- tion/enhancement thereof is not restricted to lower-order roads. The use on crushed stone Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  materials protected by the addition of small percentages of an anionic NME can be bene- ficial both in terms of durability (prevention of in-situ chemical decomposition) as well as the energy required to achieve high levels of compaction [15]. Naturally available gran- ular materials stabilised with a material compatible anionic NME stabilising agent as per a scientifically based materials design process can also, with relative ease, meet the de- sign requirement for inter-city and other highways, designed to carry relatively high traffic loadings as shown in Figure 1 [15] in association with Figure 2 [8]. These roads are associated with a high required constructed riding quality, ideally suited for the con- struction using equipment able to deliver these requirements at a low risk to contractors. The example demonstrated, showed the use of a central computerised mixing planet (Figure 10) to prepare the granular material mixed with the construction water and an anionic NME stabilising agent. The central mixing plant is able to mix the granular ma- terial (in this case a G5/6 – refer Figure 1) with a high degree of accuracy with the anionic NME stabilising agent (in the example - 1.2 per cent (containing about 0.7 per cent re- sidual bitumen)) pre-mixed with the construction water to be delivered to trucks for transportation to the road under construction (Figure 10). The water added to the mix should take into account any loss of moisture that may occur during the transportation of the mix to the construction site and the construction of the layer. Figure 10: Central mixing plant, mixing the granular material with the required construction water containing the an- ionic NME stabilising agent, using computerised control for accurate applications Figure 11 shows the constructed sub-base (in the example - G5/G6 material with 0.7 per cent anionic NME – about 0.4 per cent residual bitumen). Note the curbs put in place for the inter-city freeway that are being constructed. Figures 12 and 13 respectively show the delivery of the mix prepared in the central plant for placement by paver with the various compaction rollers ready for compaction of the 150 mm thick base layer (small roller for next to curb, smooth drum roller and pneumatic wheel roller) and the base material at the back of the paver. Figures 14 to 18 shown the compaction of the base layer and the final finishing of the layer placed to a tolerance of 2 mm accuracy. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1  The hydrophobic nature (water repellent characteristics of the anionic NME stabili- sation of the base layer was severely tested on site when more than 200 mm of rain felt during the week following the construction of the layer. Figure 19 show the water with the installed curbs acting as a channel for the flow of the water down a steep ingredient. After drying of the base layer after the severe practical test, no damage was noted (Figure 20) on the layer. It should be noted that in similar experiences with a crushed stone, ce- ment treated or normal emulsion treated unprotected layers, reconstruction of the base layer would, to all expectation, have been required due to water-damage. Figure 11: Prepared sub-base with installed curbs for the inter-city freeway under con- struction Figure 12: Delivery of anionic NME mix to site for the placement of the 150 mm base us- ing a high accuracy paver Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2021 doi:10.20944/preprints202110.0181.v1