Journal of Building Research

Micro piles were first used as a cost-effective method for stabilizing historic structures and more recently, micro piles have increased in use around the world, being used in bridges, antenna towers, slope stabilization and residential buildings. In this paper, the behavior of micro piled raft foundations in dry sandy soils has been studied numerically. This research aims to verify the validity of the proposed finite element model to be adopted in estimating the precipitation and soil stresses of micro piled raft foundations. The proposed model is based on the solid element to simulate the raft foundation, the pile and the soil mass. An explicit dynamic method was used to simulate the nonlinear static aspects of the piled-raft foundations in order to avoid the computational difficulties associated with the implicit finite element analysis. The validation of the program is based on the comparison of the results of the proposed finite element model with those of the previously conducted mini-experimental work. The comparison of the numerical and experimental results indicates that the proposed finite element model is accurate and sufficient and can be used in future work to simulate more complex practical problems for piled- raft foundations. The validation of the model used can be utilized to perform a parametric study to evaluate the effect of different factors on the foundations such us the number, the length and the diameter of the piles. The numerical results indicated that there is a significant decrease in the displacement of the Piled- Raft foundation compared to the Raft foundation for the same applied load, by increasing the numbers, diameters or lengths of the micro piles. The result of study could be utilized as guidelines for achieving economical design for micropiles raft foundation.

In this research, a thermal bonding mortar was developed for use in bonding thermal building units such as thermal bricks and thermal concrete blocks of various sizes, types, and applications in industrial furnaces. The mortar was composed of kaolin as a fine aggregate, raw kaolin, and locally produced white cement as an alternative to thermal cement. A 2% addition of sodium silicate solution was also included to form the dry mix. A heat-resistant fiber, namely fiberglass, was incorporated at varying ratios of 0.5%, 0.75%, 1%, and 1.25% by weight of the dry mixture to enhance the bonding properties of the mortar resulting in six types of mixtures, including a reference mix and five others containing the different fiber percentages. Laboratory tests were conducted on the mortar samples before burning (density, absorption, porosity, bonding strength). After which all samples were burned at a temperature of 1200°C, followed by after burning tests (density, porosity, absorption, longitudinal shrinkage). The test results indicated that mixture (D), consisting of 75% kaolin clay, 20% white cement, and 5% raw kaolin with the addition of 1% fiberglass by weight of the dry ingredients, exhibited the highest bonding strength of 1.5 N/mm². The physical test results conformed to the American Standard Specifications (ASTM C64), confirming good thermal resistance at the specified burning temperature of 1200°C.

This research investigates the effect of various pozzolanic materials on the physical, mechanical, and thermal properties of foamed concrete. An extensive experimental plan was designed for this purpose, consisting of foamed concrete mixtures with five pozzolanic additives (silica fume, glass powder, fly ash, leaf stem ash, and slag), all of which were used as a 15% substitute for cement. Porcelanite was used as a fine, lightweight aggregate for all mixtures with the exception of the reference mix. A 3:1 foaming agent-to-water ratio was used for all mixtures, which resulted in a foam density of 42 kg/m³. The test results confirmed that foamed concrete with a density of 1100 to 1290 kg/m³ would have a compressive strength of nearly 16 to 20 MPa at 28 days when pozzolanic additives are used. The use of these materials as additives also significantly reduced thermal conductivity. Specifically, the mix containing 15% leaf stem ash performed better than the other pozzolanic replacements, exhibiting the best thermal, mechanical, and physical properties.

In light of the world's focus on reducing carbon dioxide emissions and the recommendations of the Paris Climate Conference, it has become essential to address industries that contribute to the significant release of this gas, with the cement industry being a primary concern. Iraq, like other countries, must adopt a strategy for developing an environmentally friendly clinker cement industry that can be implemented in multiple phases. The first phase involves investing in comprehensive applicable studies related to the production of eco-friendly cement models, such as studies on lime cement, blended cement, and pozzolanic cement, then applying the findings of these studies into practice. The second phase requires optimal adherence to binding materials, avoiding overuse of cement, and substituting it with locally available alternatives like aggregate and gypsum, particularly in construction work where cement is not essential. The third phase of this strategy represents the necessity of initiating laboratory experiments to prepare laboratory samples of clinker at low temperatures. This has been undertaken by the working team despite the lack of advanced scientific equipment. Raw materials have been added to limestone, such as magnesium oxide and kaolinite, with the mixture being fired at low temperatures (1100-1350 °C). Although no clinker has been produced due to the absence of the required chemical reactions, this still represents a step in the right direction.

Refrigerators with thermoelectric cooling reduce high mechanical failure rates and maintenance costs then they don’t have any moving parts, in addition to offering efficient cooling and effective temperature management. The search developed a new thermoelectric refrigerator to store drugs and vaccines for medicinal usage. This refrigerator with a Peltier module (12706) operates at 14.4volts, with solar panels providing 21.1 volts and 100 watts of power. The system also includes a 4-liter plastic box with thermal insulation, an internal heat sink, a finned heat pipe heat sink, an aluminum layer, and a voltage regulator. This system also includes a 4-liter plastic box with thermal insulation, an aluminum layer, an internal heat sink, a voltage regulator, and a finned heat pipe heat sink. The efficiency of this refrigerator was measured by two trials. A normal heat sink and a 15-volt, .6-am DC power supply were employed in the second check, the solar panels and a finned heat pipe heat sink were used in the first. Conversely, to the normal heat sink, which had a coefficient of performance (COP)of 0.7, the second test COP was 2.4 at -4oC. The Peltier modules with the finned heat pipe heat sink enhanced the total efficiency by 1.5%.

Refrigerators with thermoelectric cooling reduce high mechanical failure rates and maintenance costs then they don’t have any moving parts, in addition to offering efficient cooling and effective temperature management. The search developed a new thermoelectric refrigerator to store drugs and vaccines for medicinal usage. This refrigerator with a Peltier module (12706) operates at 14.4volts, with solar panels providing 21.1 volts and 100 watts of power. The system also includes a 4-liter plastic box with thermal insulation, an internal heat sink, a finned heat pipe heat sink, an aluminum layer, and a voltage regulator. This system also includes a 4-liter plastic box with thermal insulation, an aluminum layer, an internal heat sink, a voltage regulator, and a finned heat pipe heat sink. The efficiency of this refrigerator was measured by two trials. A normal heat sink and a 15-volt, .6-am DC power supply were employed in the second check, the solar panels and a finned heat pipe heat sink were used in the first. Conversely, to the normal heat sink, which had a coefficient of performance (COP)of 0.7, the second test COP was 2.4 at -4oC. The Peltier modules with the finned heat pipe heat sink enhanced the total efficiency by 1.5%.