Abraham Mansouri

In hot‐arid climates with extreme diurnal temperature swings, achieving thermal stability through passive means remains a critical challenge in building design. This study introduces a novel 3D concrete printed (3DCP) honeycomb wall system incorporating a 30% phase change material (PCM)‐sand composite as infill. Unlike conventional strategies, this work solves the “PCM‐printability paradox” by decoupling thermal and structural functions, using sand‐stabilized PCM infill to preserve mechanical integrity while achieving unprecedented thermal performance. The cellular honeycomb geometry, enabled by additive manufacturing, maximizes internal surface area and optimizes heat exchange between infill and environment. Finite element simulations under sinusoidal thermal loading and reflective of Middle Eastern desert conditions, demonstrate an ultra‐low decrement factor ranging from 0.00170 (linear model) to 0.00440 (Gaussian model), along with a 14‐h thermal time lag. These results significantly outperform both traditional wall assemblies and previously studied PCM‐integrated systems. Beyond attenuating indoor thermal fluctuations, the PCM‐sand infill contributes valuable thermal mass to the envelope, enhancing inertia and energy efficiency. This research presents a design‐integrated path toward thermally responsive, structurally sound, and highly adaptable building envelopes, advancing the pursuit of net‐zero energy‐efficient 3DCP buildings.

Thermal resistance (R‐value) is a key metric for evaluating the energy performance of building envelopes, particularly in emerging technologies like 3D‐concrete pinting (3DCP) buildings. However, conventional methods such as heat flux meters (HFM) face challenges in 3DCP applications due to surface roughness, contact‐based limitations, and high costs. This study introduces a novel low‐cost, noncontact system integrating an MLX90614 infrared sensor and LM35 temperature sensor with an Arduino‐based platform, using the Thermometric Method (THM) to estimate R‐values from wall surface, indoor, and outdoor temperatures. A novel feature of the system is a dual‐servo mechanism that enables spatial temperature mapping over a 5 × 5 cm grid, improving accuracy by replacing traditional single point measurements with area‐based readings. Validation against the UVAL Wireless System (greenTEG) showed a maximum error of 13% under steady‐state early morning conditions, increasing to 173% in the afternoon due to thermal instability. The proposed method offers a practical, affordable, and non‐destructive solution for thermal diagnostics in 3DCP buildings, supporting the development of standardized evaluation protocols for sustainable construction.

The design freedom of three‐dimensional (3D) concrete printing (3DCP) enables complex building envelopes with integrated air cavities; however, their thermal performance in extreme climates poses a critical challenge, particularly for cavities with nonuniform geometries. This study presents a combined experimental and numerical analysis of conjugate heat transfer in a real 3DCP building envelope featuring variable‐thickness air cavities under hot‐arid conditions. A comprehensive methodological framework was employed: (1) in situ U value measurements on north and slanted east cavity walls (3.75 m tall; max cavity width, 900 mm) with and without interior insulation, (2) development of a robust numerical model to simulate conjugate heat transfer across laminar to turbulent flow regimes, and (3) whole‐building cooling load estimation for the 168 m ² structure. Results demonstrate that wide cavities (> 25 mm) develop strong buoyancy‐driven circulation ( Ra ≈ 10¹¹ at Δ T = 20 K), severely degrading insulating performance and yielding high U values of 2.67–3.29 W/(m ² K) for uninsulated walls—approximately 30% higher cooling loads than standard construction. Crucially, parametric analysis reveals that filling cavities with low‐conductivity porous media (e.g., sand and k = 0.27 W/[m K]) effectively suppresses convection, restoring thermal performance to near pure conduction levels and reducing U values by up to 82% when complemented with insulation. These findings provide essential, practical strategies for optimizing energy efficiency in future 3DCP buildings constructed in hot‐arid climates.

A three-dimensional finite element framework was developed to evaluate and optimize the performance of internal impressed current cathodic protection (ICCP) systems in elevated water storage tanks, with electrochemical kinetics incorporated through the Butler-Volmer equation to simulate potential distribution and current demand under realistic operating conditions. The influence of structural configuration was examined by comparing conical and ellipsoidal tank bases, while parametric studies assessed the effects of water resistivity, cathodic exchange current density, and anode arrangement. Results demonstrated that water resistivity below 10 Ω·m enhanced edge protection, whereas higher values exacerbated vulnerability at sharp geometric transitions. Increasing the number of anodes from three to five without altering total current output yielded negligible improvements, while a 10% reduction in cathodic exchange current density substantially enhanced potential uniformity. In the riser pipe, reducing the number of anodes from 26 to 22 led to a 10% decrease in potential distribution, placing portions of the surface outside the protected range. The findings highlight the importance of precise anode placement and system calibration to ensure compliance with standard protection criteria, and the proposed modeling approach provides a rigorous tool for the design of ICCP systems in municipal and industrial water tanks, with potential extension to incorporate time-dependent phenomena such as polarization decay and resistivity variation.

Three‐dimensional concrete printing (3DCP) is an emerging construction technology offering significant potential to revolutionize the building industry through the digital fabrication of freeform structural components. However, current wall assembly designs adapted from traditional construction often incorporate interior air cavities that can introduce heat loss challenges during the highly integrated 3D printing process. This study presents preliminary findings from ongoing research exploring sand as an alternative cavity infill material, which offers potential solutions to these challenges while enhancing overall wall thermal mass and fire resistance. In the climatic conditions of cities such as Dubai, UAE, incorporating thermal mass can help regulate indoor temperatures, reduce reliance on mechanical cooling systems, and enhance overall energy efficiency. The addition of dry sand into the cavity of a 300‐mm 3DCP wall significantly enhances thermal performance by increasing heat‐transfer resistance by 300%, extending the time lag by 9 h, and lowering the decrement factor. These improvements contribute to greater indoor climate stability and energy efficiency.

Corrosion prevention techniques such as cathodic protection (CP) are commonly applied to extend the useful lifetime of buried steel tanks in corrosive environments. Sacrificial anodes effectively supplement CP systems through controlled galvanic corrosion. For buried steel tanks, magnesium-based anodes are regularly used due to suitable current output over extended deployment periods. However, field conditions such as temperature fluctuations and proximity effects between adjacent tanks can influence CP performance. This study numerically simulates the CP of a 3.8 m diameter, 12 m long steel tank which the upper section of the tank is located at a depth of 1 m, protected by uniformly distributed magnesium anodes. To understand the importance of the current output of extended anodes, conventional anodes (i.e., 7.7 kg, 38.7 mA) and extended anodes (i.e., 9 kg, 62.7 mA) were studied. Proximity effects on anodes placed between adjacent buried tanks were also examined. In addition, the influence of temperature and concentration parameters was investigated along with a time-dependent analysis of the protected structure. Under the hottest and coldest conditions, the bottom temperature of the computational domain (in height of 6.8 m) reached 8.7°C and 11.3°C, respectively, with noticeable concentration gradients. The temperature rise necessitated increased protective current, leading to the need for additional sacrificial anodes to meet the demand. The simulation results indicated that the anodes positioned between the two tanks experienced the highest corrosion rate. After 21.5 y, approximately 85% of the mass of these anodes will be lost, with full depletion occurring shortly thereafter. This modeling approach offers valuable insights for selecting the optimal type and placement of anodes, ensuring the long-term integrity of underground infrastructure under varying thermal conditions.

Cathodic protection (CP) is widely used to mitigate corrosion and protect the substrate. However, sacrificial anodes are often undersized or improperly positioned. This study systematically investigates how anode design factors affect the CP effectiveness through computational modelling and double-objective optimisation techniques around the optimum location and dimension of anodes. State-of-the-art algorithms including the Monte-Carlo, Nelder–Mead, co-ordinate search, constrained optimisation by linear approximation (COBYLA) and bound optimisation by quadratic approximation (BOBYQA) are employed to optimise anode locations and genetic algorithm is utilised for optimising anode dimension and the objective is maximising the current output and minimising the cost. In the current study, the BOBYQA technique proved efficient in reaching the optimal response at the appropriate time. The findings indicate that in double-objective (cost and potential) optimisation of 14.5 kg anode, minimising anode radius (from 6.5 cm to 5.4 cm) and optimising the position boosts the current output by up to 15.5%. Refined anode geometries increase the average structure potentials (806 → 822 mV) by over 15 mV, translating to extended service lifetimes. In the comparison of single (cost) and double (cost and potential)-objective optimisation, about 15% more current reaches the structure and causes about 2% less anode mass loss for the same anode dimensions. Also, the results show the 7.7 kg anode performs better than the 14.5 kg anode and so output current and the percentage of current that reaches the structure of the 7.7 kg and 14.5 kg are 0.66 A and 0.46 A and 66% and 60%, respectively.

Cathodic protection as a complementary technique is widely considered in the industry along with the selection of suitable materials as well as efficient coating considerations. In cathodic protection (CP), anode produces a current output to protect the structure (cathode) and part of the current output is wasted by the grounding system. We developed a 3D, and time-dependent numerical model to simulate the anode corrosion (using arbitrary Lagrangian-Eulerian method), find the deposit formation (by interface tracking level set method), anode mass loss and current wasted by the grounding system. We also defined a CP efficiency as anode mass loss times the current percentage received by the structure. The CP efficiency can be utilized for anode quantity and placement pattern. The results showed when the conductivity of corrosion products (deposit) is lower than that of soil, the current output from the anode decreases over time. When the deposit conductivity is higher than that of soil, the current output from the anode increases in time, reaches a peak, then decreases. This is due to the competition among three factors: anode surface increase, medium conductivity change, and inhibition effect of the deposition layer. For the studied case, almost 54% of the current from the anode is wasted by the grounding system. To illustrate the significance of CP efficiency, this study compares three alternative anode configurations with the original design. It is observed that for a 14.5 kg anode, burying the anodes 2 m deeper enhances the mean potential distribution on the structure by 4%. Additionally, the configuration featuring the 7.7 kg anode, owing to its superior dimensional design, demonstrates improved performance compared to other configurations.

Cathodic protection as a complementary method is one of the most effective ways to prevent corrosion, along with coating and choosing the suitable material. There are different ways to protect the storage tank bottom. Due to the presence of the geo membrane layer and its effective and pivotal role, the use of mixed metal oxide (MMO) anodes is highly recommended. In the current study, the protection process of the above-ground storage tank bottom is simulated using MMO backfilled wire (concentric rings) and ribbon anodes (mesh grid system). In this regard, several parameters must be considered in reaching the protection criteria. The simulation results show that the effect of the limiting oxygen current density, soil resistivity and the anodic current have the greatest role. Anode depth and the spacing between the anodes are also critical factors if they have large values. Due to the importance of the number of conductor bars and feeding cables, two configurations have been presented for ribbon anodes. These configurations have a direct impact on grid resistance, rectifier size, and related costs. Finally, an economic comparison has been made regarding the use of sacrificial and MMO anodes in the form of ribbon next to wire anodes. The results show that, in the use of ribbon anodes, MMO anodes have better performance than magnesium and zinc sacrificial anodes, and the cost required for MMO linear anodes is far lower than the method of sacrificial ribbon anodes. In the present study, the cost of the MMO linear anode system is approximately 20% of zinc and magnesium sacrificial ribbon anode system cost.

Cathodic protection as a complementary method is one of the most effective ways to prevent corrosion, along with coating and choosing the suitable material. There are different ways to protect the storage tank bottom. Due to the presence of the geo membrane layer and its effective and pivotal role, the use of mixed metal oxide (MMO) anodes is highly recommended. In the current study, the protection process of the above-ground storage tank bottom is simulated using MMO backfilled wire (Concentric Rings) and ribbon anodes (Mesh Grid System). In this regard, several parameters must be considered in reaching the protection criteria. The simulation results show that the effect of the spacing between the anodes, the limiting oxygen current density and the anodic current have the greatest role. Anode depth and soil resistance are also critical factors. Due to the importance of the number of conductor bars and feeding cables, two configurations have been presented for ribbon anodes. These configurations have a direct impact on grid resistance, rectifier size, and related costs. Finally, an economic comparison has been made regarding the use of sacrificial and MMO anodes in the form of ribbon next to wire anodes. The results show that, in the use of ribbon anodes, MMO anodes have better performance than magnesium and zinc sacrificial anodes, and the cost required for MMO linear anodes is far lower than the method of sacrificial ribbon anodes. In the present study, the linear anode system has an estimated cost of approximately 20% less than the ribbon sacrificial anodes made of magnesium and zinc.