## 5 Construction of NME Stabilised Granular Pavement Layers--Practical Aspects
### NME Stabilisation Using Conventional Mixing Equipment (Water-Bowser and Grader)
#### 6.4.2 Construction of Multi-Lane Dual Carriageway Highways  
The construction of the sub-base of the multi-lane highway shown in Figures 7 and 8 (using a centralised mixing plant) as well as in Figure 10a (using a recycler) for the construction of the NME-stabilised base-layer was constructed using conventional traditional road construction equipment, i.e.,:  
* Water-bowser containing the anionic NME stabilising agent pre-mixed with the calculated construction water;
* Normal graders for the mixing and final cutting of the levels of the layer; and
* Conventional compaction equipment. The construction of the sub-base-layer of the dual carriageway with 0.7 percent (about 0.4 percent residual bitumen) of a G5/6-quality material (refer Figure 1) using conventional construction equipment is shown in Figures 14 and 15. The anionic NME stabilising agent is pre-mixed with the calculated construction water as demonstrated in Figure 5. Of specific note after construction of the first road section is the comment made by one of the grader operators expecting that the use of the new-technology application would be difficult, stating \"the process is nothing more than the construction of a normal granular layer using dirty water\". Figure 12: Recycled road with NME stabilisation opened to local traffic to provide access to houses, with no protective prime or surfacing added (note the same, pink-painted facade of the same house shown in Figure 11a). Figure 13: **(a)** Hand application of a quick-drying anionic-diluted NME prime coat to protect the base before application of the surfacing; **(b)** application of a tack coat 2 months after construction of the base-layer (opened to traffic); and **(c)** application of the surfacing. Note the little damage to the base-layer after two moths open to traffic during the holiday and rainy season. Figure 14: The granular material for the construction of the sub-base is spread along the section to be stabilised and compacted, allowing for the compaction factor. (**a**) The water-bowser containing the anionic NME pre-mixed with the required construction water is starting with the spraying of the NME mix. (**b,c**) The water-bowser is closely followed by graders that are mixing the NME stabilising agent with the construction water over the pre-determined length and width of the road. (**d**) Due to the turning movements and continued process of spraying and mixing, the construction of a section of road using conventional equipment is considerably more time consuming compared to the use of central mixing plants with paving equipment or with recycling equipment. Figure 15: Compaction of the layer with the anionic NME mixed into the layer using conventional equipment; (**a**) using a sheep-feet roller; (**b**) followed by a vibratory steel-drum roller and a pneumatic roller to create a smooth surfacing; and (**c**) a small percentage of the NME mix is retained in the tanker as an enrichment of the top of the layer before final compaction (note that, similar to normal emulsion stabilisation, clean water should not be sprayed onto the layer). The following aspects is of importance to note when using conventional equipment for the NME stabilisation of granular materials:  
* Material of a quality not previously considered for use in the base and sub-base-layers as a function of the required bearing capacity can successfully be stabilised meeting all the engineering requirements in terms of density and the specified UCS (dry and wet) and ITS (dry and wet) [5; 15; 17; 18; 20]. The compaction of a 400 m section of a G1 [21] layer to the required density will easily require a continuous process of compaction lasting 2 full days.