# Life Cycle Cost Analysis and Deterioration Patterns of Limestone Paving
## 4 Materials and Methods  
This study was based on integrating the results obtained from experimental research on regression models developed for the prediction of deterioration patterns and the life cycle cost analysis of natural stone paving exposed to different decay and weathering agents.  
(a) The _one-year-long in-use exposure of limestone paving slabs_ in a pedestrian promenade built near Capernaum, the Sea of Galilee, Israel. These limestone slabs were imported from Jordan (an arid and hot climate) and exposed to service in Israel's hot and wet climate. (For more information about the environmental conditions near the Sea of Galilee, see [54; 55]. The selected limestone had no proven performance record or established service life in a hot and wet climate. The promenade designers chose Jordanian limestone based exclusively on aesthetic and architectural criteria. The contractor declared the compressive and flexural strength of the stone prior to the execution of paving works and found it met the standard requirements for building stones, see Table 1, and the maximal load scheme calculations. However, stone defects (decay) and failure (cracks) were observed in the promenade only one year after the implementation of Jordan limestone slabs; see Figure 2. This research adopted the definitions of \"defect\", \"failure\", and \"defective performance\", which are recommended by [52; 56]. The ratio of stones with defective performances (measured by the number of defective slabs) in the promenade was 15%. The chemical, physical, and engineering properties of the new (unaged) stones and one-year-long in-use aged stones were tested to reveal the causes and trends of stone deterioration upon the effect of particular environmental and service conditions.  
(b) The _accelerated short-term ageing_ of Jordan limestone and the reference limestone of proved long-term in-use service life was carried out by exposure to cycles of wetting/drying and UV radiation for 1000 h (QUV test [36]). The conditions during the QUV test were chosen under the natural regimes of rain cycles and the intensity of UV (ultra-violet) radiation in the area of the Sea of Galilee (Lake Kinneret), Israel [57]. This experimental stage was conducted to reveal the degradation trends of Jordan limestone under the effect of agents, characterizing the service conditions of external stone paving. The chemical, physical, and mechanical properties of the new and in-lab aged stones were tested, and the trends of deterioration of the stone exposed to ageing agent were revealed.  
(c) The _comparison between the performance characteristics_ of the paving limestones tested after one-year-long in-use exposure and accelerated short-term ageing (Performance characteristic: the physical quantity that is related to the critical property [52]. This stage reveals if accelerated short-term ageing exposure is reliable for the performance evaluation of external paving stones used in hot and wet climates.  
(d) _The rate of Jordan limestone degradation upon the effect of different ageing agents_ was estimated compared to that of the reference limestone. This estimated result was then used for the mathematical regression models.  
Figure 2: _Cont._