## 5 Conclusions  
The need for rapid repairing runway pavements has grown fast over the years, both for civil purposes and for peacekeeping missions. Therefore, there is the need for a technology that could be applied balancing conflicting objectives of resistance and rapidity. At this purpose, on-site repairs are more versatile than modular repairs currently used in the military sector because they can be adapted to different conditions. The specific sector of runway construction currently needs the comparison of technical performances offered by the innovative materials used for on-site repairs. In Italy, the Laboratory of the Italian Air Force (2 nd Department of Genio) analysed technical and economic performances of several types of rapid runway repairs having the C-130J aircraft was as design aircraft. 12 materials currently used for pavement repair have been tested to evaluate their laboratory and on-site performances at different times. This paper presents the first experimental results obtained on the following materials:  
* 2 bituminous emulsions,
* 5 cement mortars,
* 4 cold asphalt mixes,
* 1 expanding resin. The experimental study involved two phases:
* laboratory tests on all materials except resin to focus on:
* ease of mixing and application;
* percolability (for emulsions, mortars and concretes);
* Marshall stability (for cold asphalt mixes). * on-site experiments on the materials which performed the best for repairing. A cold asphalt mix, a cement mortar, an ordinary cement concrete and the expanding resin were used to repair four 10 m\({}^{2}\) widespread areas. All three tested mixes required time, temperature, and procedures compliant with those used to lay ordinary cement and bituminous runway pavements. On the contrary, the expanding resin required dedicated instruments to be injected. The bearing performances have been evaluated using the ACN/PCN system (for the three mixes) or LWD (for the expanding resin). \begin{table}
\begin{tabular}{c c} \hline \hline
**Material** & **Cost (\#/m\({}^{2}\))** \\ \hline B3 & 180 \\ M1 & 50 \\ M4 & 75 \\ \hline \hline \end{tabular}
\end{table} 
Table 19: Unit cost of the examined rapid runway repair (RRR). The on-site results highlighted that:  
* it is not possible to repair runway pavement with expanding resin for two reasons: its strong expansion, even up to 20 cm over the desired level, and its bearing performances. Indeed, the LWD tests showed a decreasing value of deformation moduli over maturity time;
* the tested cement mortar M4 (one-component fast setting and hardening cement mortar with graded aggregates) ensures the fastest runway reopening in presence of a permanent repair of the damaged concrete pavement: 6 h after the work, the runway can be opened to traffic for 10,000 coverages of the design aircraft;
* surface filling (up to 6 cm) with the cold bituminous mixture B3 (bicomponent premixed cold asphalt with water as catalyst) and deep filling repair with the concrete M1 (ordinary concrete mixed with CEM I 32.5) have similar performances: both allow the reopening to traffic after 18 h maturity time, but for only 1000 coverages of the C-130J aircraft. Indeed, M1 and B3 require 7.5 days-age to support 10,000 coverages. B3 and M1 are both suitable for repairing flexible and rigid pavements. Finally, it was also observed that the unit costs of the examined materials widely vary: B3 has a higher economic impact than that of M1 and M4, mainly due to the material since the costs of machines and works to have the rehabilitated pavement are comparable. The results also provide a framework and a reference for any further study into specific cases using additional materials. All test methodologies can be applied to simulate with the software FAARFIELD (Version 1.41, Federal Aviation Administration, Washington, DC, USA) a fleet of almost any civil aircraft, therefore the procedure could be replicated for further analysis.