# Life Cycle Cost Analysis and Deterioration Patterns of Limestone Paving
## 5 Results and Discussion
### Assessment of the Life Cycle Costs of Paving  
#### 5.2.1 Life Cycle Cost Modeling Approaches for Stone Pavements  
The life cycle costs of natural stone paving detail comprise three elements: the initial construction cost (C), the annual maintenance costs (M), and the end-of-life replacement costs (R). Figure 9 illustrates the sequence of costs over a single life cycle of natural stone paving in detail. This figure illustrates annual maintenance costs of 1% of the construction costs and assumes that the pavement will be used for one more service life cycle; therefore, the end-of-life replacement costs are avoided. The maintenance of pedestrian pavement is carried out continuously based on periodical inspections (twice per annum) and the assessment of the condition; the deteriorated slabs are replaced, and the sinking slabs are replaced after the repair of the bedding pavement layer. The annual costs of this procedure are estimated at 1% of the construction cost.  
Considering the conducted tests, it is estimated that the paving and structures covered with Jordanian stone exhibit an accelerated deterioration pattern. The life cycle of the paving components is expected to range from a minimum of 1 year (as observed in the  
Figure 8: The variation coefficient of the properties of the limestone from Jordan. NUPL—the new (unweathered) paving limestone from Jordan. UWPL—the used (one-year in situ weathered) paving limestone.  
Figure 9: Life cycle cost flow for paving stones with standard deterioration pattern (without failure conditions).  
promenade case study) to a maximum of 20 years, instead of the original 24 [66]. Staged replacement work will be necessary, with the current requirement to replace 15% of the stone slabs and to seal the cracked joints with suitable cement mortar. It is also assumed that the dismantling costs will be 0.12C--12% of the construction costs (where C is the reinstatement cost per square meter of paving).  
The research method uses field surveys designed to identify the financing needs and sources. Subsequently, a model for estimating the costs was developed, distinguishing between various financing sources, as demonstrated through two typical projects: a residential construction project for sale and an office building construction project for rental purposes (a \"yielding\" project). Running the model on these typical projects allowed for the comprehensive characterization of the life cycle costs flow, their scope, and their dependency on various parameters.  
Figure 10 depicts the actual field survey datapoints gathered. Two deterioration patterns were suggested to characterize the deterioration progress: linear deterioration and exponential deterioration. Both the patterns have a high correlation coefficient with time, despite the small number of datapoints available for similar failure conditions of natural stone pavement. This methodology was developed and validated in prior research [15; 16; 17].  
In light of this, a comparison was made between the costs to the owner under normal wear conditions (without replacements until a life cycle of 24 years) and costs under accelerated wear conditions in two wear patterns (Figure 9):  
- A linear wear pattern (uniform wear rate).  
- An exponential wear pattern (initially rapid wear rate that decelerates over time).