# Life Cycle Cost Analysis and Deterioration Patterns of Limestone Paving
## 5 Results and Discussion
### Properties of Unweathered and In situ Aged Paving Limestones
It should be emphasized one more time that RPHL, chosen as a reference stone in the current research, is well known for its satisfactory long-term durability in different in-use  
Figure 4: Physical engineering properties of paving stones. RPHL—reference paving hard limestone; NUPL—new (unweathered) paving limestone from Jordan; +—positive error; —negative error; CV—coefficient of variance. exposures to the various environmental conditions in Israel. There is evidence about the lifespan of RPHL external pavements, which is up to 50 years [16]. In this research, a model for the prediction of the service life of claddings under standard conditions was developed, and the service life of stone under standard conditions was defined. The one-year in-use exposure of paving limestone from Jordan to the hot and humid environment in the vicinity of the Sea of Galilee mostly led to an improvement in the water absorption characteristics of this stone and its abrasion wear (see Figure 6). The total water absorption and the surface absorption capacity of the NUPL have risen by 22% to 40% because of in-use weathering. The water absorption characteristics of the weathered (UWPL) and new (NUPL) limestone paving showed marked differences after one year of environmental exposure (Figure 6). The total water absorption and surface absorption capacity increased by 22% to 40% in the UWPL, indicating increased porosity due to weathering. However, capillary water absorption remained relatively stable, suggesting that the increased absorption occurred primarily in the larger pores and the microcracks rather than the fine capillary networks. The coefficient of variance (CV) for water absorption and evaporation was notably higher in the UWPL, pointing to non-uniform degradation across the stone slabs. This heterogeneous deterioration can compromise the overall durability of the paving. These changes--increased total absorption, stable capillary action, and high variability--collectively indicate accelerated wear in the UWPL after just one year. This rapid deterioration underscores the importance of proper material selection and maintenance of limestone paving in challenging environments. Figure 5: Water absorption and evaporation characteristics of paving limestones. RPHL—reference paving hard limestone; NUPL—new (unweathered) paving limestone from Jordan; +—positive error; —negative error; CV—coefficient of variance. The water evaporation capacity of the unused and used limestones from Jordan, the NUPL and the UWPL, respectively, was much smaller than that of the reference limestone, the RPHL; see Figure 7. The exposure of the stones to the cycles of UV radiation led to the decreased water evaporation capacity of all the studied stones. The water evaporation capacity of the limestone from Jordan after UV exposure became more insufficient, i.e., 41% vs. approximately 50% before UV exposure. Thus, 59% of the absorbed water was entrained in the NUPL and the UWPL after QUV ageing. A low water discharge might facilitate limestone decay processes [61] No difference was observed between the mean water evaporation capacity of the new and used limestones from Jordan, the NUPL and the UWPL, respectively, before and after their exposure to the QUV test. However, after the QUV test, the absolute variation in water evaporation capacity was much higher in UWPL than in NUPL, i.e., 25% vs. up to 7%, respectively. Thus, the QUV test could be adopted as a valuable method to reveal the discrepancies in the water discharge of paving limestones aged by different weathering agents. The variation coefficients of the properties of limestones from Jordan, the NUPL and the UWPL, checked before and after the QUV test, are shown in Figure 8. Surface water absorption capacity is the property that was the most affected by ageing, with variation coefficients ranging from 28% to 38%. The water evaporation capacity during 24 h varied from 3% to 16%.