# Advances in the Study of the Behavior of Full-Depth Reclamation (FDR) with Cement  
[PERSON]  
1 Department of Civil Engineering, University of Burgos, c/Villadiego, s/n, 09001 Burgos, Spain 1  
[PERSON]  
1 Department of Civil Engineering, University of Burgos, c/Villadiego, s/n, 09001 Burgos, Spain 1  
[PERSON]  
2 Mechanical Engineering Department, University of the Basque Country UPV/EHU, P\({}^{\circ}\) [PERSON], 2, 48013 Bilbao, Spain 2  
Sparish Institute of Cement and Its Applications (IECA), c/[PERSON], 53, 1\({}^{\circ}\), 28003 Madrid, Spain 2  
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Footnote 2: email: {h.s.t.} _Applied_  
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chemical additives (Portland cement, hydrated lime, calcium chloride, and fly ash) and bitumen additives (bitumen emulsions). The most employed stabilizers worldwide are bituminous emulsions and Portland cement [3; 6; 7; 8; 9]. In this case, full depth reclamation with Portland cement (FDR-PC) yields a base course with significant structural capacity, for which the existing road is used as a \"quarry\" or source of aggregate. With this technique, the materials in the road are reused by pulverizing them, and adding cement, water, and sometimes a small percentage of aggregate or even an additive, in the proportions established through preliminary testing. This mixture is compacted and cured to form the course with the greatest structural strength in the new pavement [6; 10; 11; 12; 13; 14]. This procedure is, without a doubt, more effective for ensuring user comfort and safety than reinforcing or rebuilding heavily cracked or deteriorated pavements. FDR with cement has a number of technical, economic, and environmental advantages [15]. It results in a longer-lasting, less erosive, and water-resistant pavements, able to withstand the stress from traffic loads that reach the subgrade more efficiently. This high-performance technique requires no manufacturing plant or transportation of materials. It is also environmentally friendly; since the materials are reused in their present location, new aggregate deposits need not be found, nor existing quarries over-mined. The elimination of transport reduces CO\({}_{2}\) emissions and the associated impact on the road and the traffic [3; 16]. Furthermore, the reclaimed pavement can be regarded as solid waste generated from deteriorated roadways [5]. Finally, a life cycle cost analysis of construction and maintenance practices indicates that the maintenance and rehabilitation strategy based on pavement in situ recycling is the least costly, providing savings to the overall economic performance of the road pavement over the life cycle [17]. In recent years, around one million square metres of pavement were recycled in Spain annually, covering a total surface area of nearly 30 million square metres between 1998 and 2018 [18]. This is a proven method that has been widely used and has shown exceptional results to date. Based on the many advantages described, it has a promising future. Pavement recycling as a rehabilitation method is a technique that was first used in the United Kingdom in the 1940s to repair secondary roads damaged during World War II [19]. However, FDR did not make a comeback until the mid 1980s, when a better understanding of the characteristics of semi-rigid pavements and the development of advanced machinery led to the inclusion of cement in the mix [1; 20]. In Spain, cold-recycling techniques first came into use in 1991 after several unsuccessful hot-recycling experiments in the early 1990s [19; 21]. The first cold-recycling trial was in Huelva, where the Ministry of Public Works recycled a 12 km stretch of road, N-431, to a depth of 30 cm [22]. Other regions subsequently undertook experiments of their own, and in some cases, such as in the region of Castilla y Leon, standardized the technique through widespread use. The number of recycled roads quickly grew, ultimately reaching the aforementioned 30 million square metres.