Stabilization

Fuel oil flyash (FFA) produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR), unconfined compressive strength (USC) and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP), which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization

The validity of laser diffraction system to reproduce hydrometer results for grain size analysis in geotechnical applications.

The grain size analysis plays a significant role in any geotechnical study. The grain size analysis, by means of sieving, is usually used for coarse material of particle size > 75 μm. For the fine material; the sedimentation methods are frequently adopted (e.g., hydrometers). Other methods also exist such as electron microscopy, digital image analysis and laser diffraction. The fine geomaterials commonly undergo agglomeration which makes the recognition of individual grain size using digital image analysis or electron microscopy challenging. To facilitate and enhance the grain-size analysis, this study was conducted using the Laser Diffraction System (LDS). Seven samples with different nature (composition and texture) and sources were analyzed by hydrometer and LDS. For LDS, various factors were studied such as air pressure, sonication, dilution, refractive index, and distribution method (volume or number). The results were compared qualitatively and quantitatively based on soil classification systems, fractal dimensions, and other parameters. Furthermore, this study provided a novel criterion to determine which LDS distribution method (volume or number) is to be used depending on the Liquid Limit. A combined sieve-LDS system is recommended to obtain the entire grain size distribution. It is concluded that the LDS is a viable technique that can replace the time-consuming hydrometer method to assess the grain-size distribution

Development of eco-friendly hollow concrete blocks in the field using wasted high-density polyethylene, low-density polyethylene, and crumb tire rubber

A new configuration of hollow concrete blocks was fabricated in the field. Three distinct types of hollow concrete blocks were produced to assess the effectiveness of such blocks in the market. In addition, the experimentally determined thermal resistance was used to calculate the expenses, oil consumption, and CO2 emissions. Blocks made with crumb rubber failed in the ASTM C129 tests for non-load bearing compressive strength, whereas those made with the control and high-density polyethylene (HDPE) met the standard requirements. It was shown that the inclusion of rubber particles lowered the strength by 56%. The control block with the new configuration used in this investigation has a thermal conductivity of 53.4% lower than the commercial hollow blocks. While the inclusion material had a smaller impact than the arrangement of holes, HDPE thermal conductivity decreased by 6.4% compared to the control block. Likewise, the control-block wall's layout can reduce the power consumption by 53%. Moreover, the HDPE and low-density polyethylene (LDPE) blocks lowered the power consumption by 54 and 57%, respectively, saving roughly 4.26 ($/m2.year). Furthermore, the oil consumption and CO2 emissions were decreased by 56% when HDPE with 20% replacement was utilized. Reducing oil consumption as an energy source implies cleaner air and a lower carbon footprint. Therefore, it is recommended to incorporate these waste materials in the production of concrete blocks in order to reduce CO2 pollution in the world