Advances in Civil Engineering

Using waste materials in road construction is a sustainable technique that will promote waste reduction, a cleaner environment, cost savings in road construction projects, and serve as an alternative material. This study evaluated the performance of hospital waste ash (HWA) modified asphalt mixtures. The modified asphalt mixtures were produced using HWA as mineral filler at 0%–100% at an interval of 10% by weight. The performance of the mixtures was evaluated with the Marshall, Cantabro, and retained strength index (RSI) tests. The Marshall parameters indicate that the modified asphalt mixtures met the General Specification for Roads and Bridges of Nigeria with satisfactory results. Except for mixes prepared with 90% and 100%, HWA-modified mixtures fulfill the RSI and Cantabro durability requirement at up to 80% filler content. However, to ensure the optimum performance of the HWA-modified asphalt mixtures, a 40% HWA is recommended.

Conductive concrete with nanographite–cupric nickel sulfate ore was prepared in this paper. As a new type of multifunctional multiphase conductive building material with conductive, electrothermal, electromagnetic shielding, piezoresistive properties, etc., nanographite–cupric nickel sulfate ore conductive concrete will have a wide range of applications in snow melting, electromagnetic shielding, cathodic protection and structural health monitoring, and other fields. In this paper, different dosage of nanographite and cupric nickel sulfate ore admixture that the mixture was excited by alkali excitation, ultrasonic vibration and combined alkali excitation and ultrasonic vibration, respectively were used to study the electrical conductivity and mechanical properties of conductive concrete, 36 groups of nanographite–cupric nickel sulfate ore conductive concrete specimens and seven groups of comparative specimens were cured for 28 days, and the unconfined compression test, three-point bending test, and electrical conductivity test were carried out. The results show that the electrical conductivity and mechanical properties of the specimens with 6% nanographite and 60% cupric nickel sulfate ore were the best, with the compressive strength, flexural strength and resistance reaching 40.83 MPa, 6.81 MPa, and 5,850 Ω·cm, respectively. Compared with the comparative specimens, the compressive strength and the flexural strength of the specimens are increased by 38.5% and 20.4%, respectively, and the resistivity is decreased by 55.7%. This shows that the alkali excitation-ultrasonic vibration activation method can not only improve the electrical conductivity of nanographite–cupric nickel sulfate ore conductive concrete pavement but also ensure the stability of its mechanical properties.

In this paper, the three-dimensional (3D) seismic plastic damage performance of the Ermenek Arch Dam (220 m), which was built in Karaman, Turkey, in 2009, is investigated by including different gallery spaces. 3D modeling of the dam is performed using the finite-difference method, and four various gallery spaces are added to the dam model considering their original oval geometries. WIPP-Drucker (WD) material model is utilized for the dam’s concrete material in creep and seismic damage analyses. Moreover, the Mohr–Coulomb material model is utilized for the foundation. Quiet nonreflecting and free-field boundary conditions are taken into account in the earthquake analyses, and reflecting (fix) boundary condition is used in the factor of safety (FOS) analyses in order to minimize the reflection of earthquake waves at the boundaries. First, the FOS analyses of the Ermenek Dam are performed considering the WD material model, and the optimum mesh space is determined according to FOS analyses. Then, 3D earthquake analyses are performed for 10 important strong ground motions that occurred in Kahramanmaraş, Hatay, Malatya, and Gaziantep in 2023. As a result of the FOS analyses, it is suggested that the mesh length of arch dams should not be chosen randomly while performing the earthquake analyses, and the FOS analyses of arch dams should be carried out using the WD material model before choosing the mesh space. Besides, it is concluded that selected ground motions for seismic analyses have created significant plastic damage around the galleries of the Ermenek Arch Dam, and gallery spaces are of great importance for the seismic plastic damage behavior of arch dams.

Understanding the effects of in-situ drying–wetting pattern on the stress-dependent water retention curve of intact loess is vital for addressing geotechnical problems in loess regions. The principal objective of this study is to investigate the influence of in-situ drying–wetting on the stress-dependent water retention behavior of intact loess. To meet this objective, six drying–wetting tests were carried out using a suction- and stress-controlled pressure plate extractor. Intact loess was sampled from three different depths: 1.0, 3.0, and 5.0 m. For specimens from each depth, two vertical net stresses (i.e., 0 and 50 kPa) were applied prior to the drying–wetting cycle. Experimental results revealed that the in-situ drying–wetting pattern greatly affected various aspects of the water retention behavior, particularly the hysteresis. The hysteresis of the specimen from 5.0 m is about 82% and 77% larger than that of the specimens from 1.0 and 3.0 m, respectively. This is because the specimen from 5.0 m has some large-size pores (i.e., >400 μm), which were not found in specimens from 1.0 and 3.0 m. These large-size pores enhance pore nonuniformity and hence the hysteresis. Furthermore, specimens from different depths consistently showed a reduction of hysteresis when the stress was increased from 0 to 50 kPa. The reduction is the most significant for a specimen from 5.0 m due to the collapse of large-size pores under compression.

In this paper, the factors causing the change in carbon emissions from direct energy consumption in the construction industry in Beijing–Tianjin–Hebei are decomposed using the logarithmic mean divisia index (LMDI) method to analyze the effect values and contribution rates of each macrofactor. Based on the decomposition results and given relevant national policies, five scenarios are set up for each influencing factor, and a regression stochastic impact on population, affluence, and technology (STIRPAT) with ridge regression analysis is applied to each scenario combination for scenario prediction, forming a scientific and reasonable theoretical system to predict the future time of carbon peaking and carbon neutrality in the construction industry of Beijing–Tianjin–Hebei. The results show that (1) energy intensity and energy structure have a suppressive effect on direct energy consumption carbon emissions in the construction industry in Beijing–Tianjin–Hebei, and the industrial structure, economy, and population will promote an increase in carbon emissions. Energy intensity and the economy have a more significant effect on carbon emissions in the construction industry. (2) The peak year of carbon emissions varies with different scenarios, and the energy efficiency scenario achieves peak carbon in 2028, the earliest peak time, and the lowest peak, as it is the optimal emission reduction projection scenario.

There are many advantages of reasonably determining the affected zone and its construction sequence for the multiline parallel pipe-jacking construction, such as convenient to reasonably arrange the pipeline section distribution mode, reducing the construction safety risk, and construction difficulty. Combined with the engineering construction practice of the multiline parallel pipe-jacking project for the north city drainage and flood control project through Chu River in Hefei, the strength reduction method has been utilized to study the surrounding stratum FOS for the pipe-jacking construction unloading under different overburden thickness Hs, different clear distance D, and different river water depth in this paper. The formula of the minimum critical overburden thickness Hs_min and the minimum critical clear distance D_min of the surrounding stratum self-stability during pipe-jacking construction unloading have been derived. The division method of the affected zone for the multiline parallel river-crossing pipe-jacking construction which behaves as the mutual influence nonself-stability zone, the mutual influence self-stability zone, and the no mutual influence self-stability zone has been proposed. For further discussion, the construction sequence of the multiline parallel river-crossing pipe jacking has been studied.