In regions characterized by extreme cold and elevated altitudes, notably in the northwest, the mechanical characteristics of construction materials such as Ultra-High Performance Concrete (UHPC) are critically impacted by ambient temperatures. This study investigates the mechanical properties of UHPC subjected to low-temperature curing environments, conducting uni-axial compressive and splitting tensile strength tests on UHPC specimens, which comprise water, dry mix, and steel fibers. These specimens were cured at varied temperatures (-10℃, -5℃, 5℃, 10℃). Utilizing damage theory principles, the loss rate in compressive strength of UHPC post-curing was quantified as a damage indicator, revealing internal degradation. A predictive model for damage under low-temperature maintenance was developed, grounded in the two-parameter Weibull probability distribution and empirical damage models. Parameter estimation for this model was achieved through the least squares method, informed by experimental data. The findings indicate a rapid increase in UHPC’s mechanical strength at all curing temperatures, with 7-day strength achieving approximately 90% of its 28-day counterpart. A positive correlation was observed between the mechanical strength of UHPC, curing temperature, and age. Despite a reduction in mechanical strength due to low-temperature curing, UHPC was found to attain anticipated strength levels suitable for construction in cold environments. The proposed model for predicting UHPC damage under low-temperature conditions demonstrated efficacy in estimating the strength loss rate, thereby offering substantial technical support for UHPC’s application in northwest regions.

In the realm of civil engineering and industrial construction, the infusion of waste materials into road pavements has emerged as a pivotal strategy for augmenting the attributes of asphalt mixtures while concurrently mitigating the environmental repercussions associated with waste. This investigation delineates a dry method for the preliminary treatment of waste paper, preceding its amalgamation into asphalt mixtures. The focal point is the incorporation of waste paper and Cement Kiln Dust (CKD) as modifiers in Stone Mastic Asphalt (SMA). It is posited that the inclusion of waste paper fibers can substantially elevate the SMA's flexibility and crack resistance. Simultaneously, CKD is purported to bolster the asphalt's strength and durability through its cementitious characteristics. A series of SMA blends were formulated, integrating waste paper and CKD in varied proportions ranging from 0.2% to 1% by weight. Subsequent evaluations encompassed analyses of air voids, density, drain-down characteristics, Indirect Tensile Strength (ITS), and Marshall Stability. The outcomes revealed that the drain-down test exhibited enhancements in volumetric parameters, notably density and air voids. Concomitantly, there was a 33% increase in Marshall Stability and a 37% improvement in ITS. Additional advancements were observed in Marshall Flow, Tensile Strength Ratio (TSR), and skid resistance. In summation, this study establishes that waste paper, when appropriately treated and amalgamated with CKD, can be efficaciously utilized in SMA mixes, yielding mixtures with superior volumetric and mechanical properties. This methodology not only augments the stiffness and minimizes binder drainage but also enhances rutting resistance. Most crucially, it paves the way for sustainable and ethical practices in the reuse and recycling of waste materials.

This study introduces a novel methodology for optimizing the design of small dams in the Western Desert of Iraq, a region characterized by its vast expanse and significant flood water influx, particularly in the Horan Valley. The approach integrates Geographic Information Systems (GIS) with a custom-developed Visual Basic program, termed the Optimal Height and Location Model (OHALM), to determine the most effective dam height and location. The initial phase of the study involved utilizing GIS to identify potential dam sites in Horan Valley, based on a set of defined criteria. Subsequently, OHALM was employed to ascertain the optimal dam height, taking into account economic factors such as minimal evaporation losses and maximal water storage capacity. The study culminated in the selection of 13 proposed small dam sites, with height estimations ranging between 12.5 to 14 meters, allowing for a total water storage capacity of approximately 303 million cubic meters. This capacity expansion resulted in an increase of the valley's water body area from 15 square kilometers to 90 square kilometers. Comparative analysis of these proposed dam heights with those of existing structures in the valley revealed a relative variance of 10.4% in the upstream, 7.2% in the midstream, and a comparable percentage in the downstream areas. The research highlights the efficacy of integrating GIS and Visual Basic programming for the strategic development of water resource management systems, particularly in arid regions. This innovative approach demonstrates the potential for significant improvements in water storage and management, addressing the critical need for sustainable water resources in arid environments.

In response to the mechanical performance alterations of PVC-P geomembranes due to improper handling or subgrade particle action during construction and operation, a series of axial tensile tests on PVC-P geomembranes with various scratch damages were conducted. Multifactorial variance analysis was performed using Python, and a multivariate regression model for the fracture strength and elongation at break of scratched PVC-P geomembranes was developed using SPSS. The precision of the regression model was evaluated using parameters such as the coefficient of determination (R²), mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE). The results indicated that the fracture strength and elongation at break of PVC-P geomembranes are significantly affected by a combination of scratch angle, length, and depth. The impact on elongation at break is greater than on fracture strength, with the scratch angle having the most significant effect. The developed multivariate regression model yielded R² values of 0.98 and 0.97 for fracture strength and elongation at break, respectively. The MAEs were 0.62 kN/m and 7.96%, and the MAPEs were 3.06% and 5.13%, respectively. The RMSEs were 0.84 kN/m and 12.08%. The high fitting accuracy of the model suggests its utility for evaluating the mechanical performance of PVC-P geomembranes with scratch damage.