Insights from bond-slip investigations in different reinforced concrete mixtures for LNG containment

Understanding the concrete-steel interface's behavior at cryogenic temperatures is important for designing concrete for direct liquefied natural gas (LNG) containment; such behavior is currently unclear. Hence, the work conducted involved pull-out testing in providing insights on the bond-slip relationship and the development of internal strains, which have seldom been measured in cryogenic concrete. Deformed cryogenic steel rebars (16 and 19 mm diameter) were embedded in cylindrical concrete specimens made with either traprock or limestone aggregates, with and without air entrainment (AE). Embedded foil and vibrating wire gages monitored the concrete and rebar's internal strains during cooling and pull-out testing. Pull-out testing involving applied stresses ranging from 34.5 to 241.5 MPa was conducted at normal and cryogenic temperatures. Bond stress was similar in both aggregate types but increased with rebar diameter within the applied stress range. The gages indicated that the rebar and concrete showed similar strain patterns in AE and non-AE traprock, and the AE limestone concretes during cryogenic cooling. However, the rebar gages responded to expansive movements below −20 °C in the non-AE limestone concrete. Bond stiffness degradation occurred at higher applied tensile stresses with AE in limestone concrete but at similar tensile stresses in AE and non-AE traprock concrete

Effect of gas-to-liquid biosludge on soil properties and alfalfa yields in an arid soil

Soils in Qatar are relatively poor in fertility. Hence, imported top soils and soil enhancing materials are used to improve agricultural yields. Therefore, this work investigated the potential of using gas-to-liquid (GTL) biosludge as a soil conditioner. It sought to increase crop yields in an arid soil with positive environmental footprint in terms of fertilizer application savings, waste utilization and minimization of landfilling. A fodder crop, alfalfa (Medicago sativa), was grown under semi-controlled pot conditions for 12 months. The plant-growth media involved soil, soil + fertilizer, soil + 3% compost, and soil plus five (0.75–12%) biosludge contents. Pertinent properties of the soils, the resulting leachates, and plant growth parameters were analyzed at set periods. Biosludge content generally increased the total porosity and volumetric abundance of different pore types, which in turn affected plant performance, especially the plant height. Alfalfa yield in terms of plant height, aboveground fresh biomass weight and the number of tillers decreased with increasing biosludge content. Mixtures with 0.75–3% biosludge content showed comparable or better plant yield in contrast to the soil, fertilizer and compost controls. The concentration of chemical species in the leachate and plant biomass of biosludge treatments were either lower or similar to the fertilizer and compost controls. Regression modeling identified leachate phosphorus concentrations, soil iron concentration and clay content as the most influential variables for the aforementioned plant performance parameters. The results suggest that GTL biosludge could potentially enhance arid soil properties and improve alfalfa yields

Dataset on the influence of gas-to-liquid biosludge on arid soil properties and growth performance of alfalfa

The dataset presented here is related to our research article entitled “Effect of gas-to-liquid biosludge on soil properties and alfalfa yields in an arid soil” [1]. It relates to selected performance parameters of alfalfa grown in an arid soil amended with five different (0.75–12%) gas-to-liquid biosludge contents, and selected properties of the soil determined using several material characterization techniques. A detailed description of the raw data relating to figures on alfalfa performance parameters such as fresh biomass weight, plant height, the number of tillers, and biomass elemental content in the companion article is provided alongside additional data on the number of days to flowering. The underlying data for leachate from the soil and underlying spectra and diffractograms for the proton nuclear magnetic resonance (1H-NMR) and X-ray diffraction (XRD) data, respectively, shown in the companion article are presented. These show changes in the pore structure characteristics and the mineralogical composition of the soil, soil-fertilizer, soil-biosludge, and soil-compost mixtures tested over time. Additional data showing the effect of the amendments on the bulk and particle densities of the soil is presented. The dataset demonstrates the influence of the industrial biosludge on arid soil properties and alfalfa yields (Kogbara et al., [1])

Recycling industrial biosludge for buffel grass production in Qatar: impact on soil, leachate and plant characteristics

The agricultural industry in Qatar is highly dependent on using soil enhancing materials due to challenging soil and climatic conditions. Hence, this work investigated the potential of industrial biosludge from the wastewater treatment plant (WWTP) of a Gas-to-Liquids (GTL) plant to enhance an arid soil compared to fertilizer and compost. A fodder crop, buffel grass (Cenchrus ciliaris), was grown in semi-controlled pots containing a typical Qatari agricultural soil and admixtures over a 12-month period. The treatments included soil plus five biosludge percentage contents: 0.75, 1.5, 3, 6 and 12%. These were compared with soil only, soil plus 20-20-20 NPK fertilizer and soil plus 3% compost controls. Analyses of soil physical and chemical properties, the resulting leachate, and plant growth characteristics were conducted at set periods. The results indicate that up to 3% biosludge content led to better plant growth compared to the controls, with the optimum at 1.5% biosludge content for all growth characteristics studied. Biosludge addition to soil increased the volume of different pore types, especially micropores, which enhanced water retention and influenced plant growth. Regression modelling identified leachate Si and Fe concentrations, and biomass K content as the most influential variables for fresh biomass weight, plant height and the number of tillers, respectively. Biosludge addition to the soil around the optimum level did not cause detrimental changes to the resulting leachate and plant biomass. The findings of this work could lead to minimization of biosludge landfilling and allow for savings in fertilizers and irrigation water in arid regions

Dataset comparing the growth of fodder crops and soil structure dynamics in an industrial biosludge amended arid soil

The dataset in this work compares the response of two fodder crops, alfalfa (Medicago sativa) and buffel grass (Cenchrus ciliaris), to industrial biosludge amendment of an arid soil in the State of Qatar. It also evaluates the response of soil structure parameters in the biosludge-amended soils containing the different fodder crops. The dataset relates to our previously published works detailed subsequently. The underlying data comparing the water storage capacity and pore structure evolution of the planted soils treated with 0.75, 1.5, and 3% biosludge contents, which showed good outcomes in the companion articles, alongside soil only and soil-fertilizer controls, are presented. These are shown in terms of the percentage of irrigation water leached, and variations in the logarithmic mean T2 (i.e., T2LM - a proxy for mean pore size) and cumulative porosity, respectively. Data on plant growth parameters such as the number of days to flowering, plant height, and aboveground fresh biomass weight in individual replicates of the different treatments as a percentage of the soil-fertilizer control are also shown. The dataset shows the different responses of both plants and the planted soils to amendments with industrial biosludge from the wastewater treatment plant of a gas-to-liquid (GTL) plant

Properties of a Terpolymer-Treated Soil: A ¹³C NMR Study

The Young's modulus and the secant modulus of a terpolymer-treated soil as a function of the polymer's characteristics are discussed in the context of a more general inelastic property known as the toughness parameter. The soil chosen was a sample of the State of Qatar subsoil. The terpolymer, designated TPAM, was characterized by a backbone structure of acrylamide, anionic carboxylate, and cationic (3-acrylamidopropyl-trimethylammonium chloride) repeat units. The backbone unit ratio was estimated from ¹³C NMR analyses. TPAM was synthesized by straightforward NaOH hydrolyses of an acrylamide/cationic copolymer. The correlations between the NaOH molarity of the hydrolysis solution, with the corresponding ratio of the anionic and cationic units, were shown to have a significant influence on the value of the toughness parameter. It is speculated that controlling the anionic and cationic ratio of a terpolymer is a general approach to optimize the toughness parameter of treated soils. Measurements of the molecular weight of TPAM were made, and comments on the importance of this feature are given. The equivalent viscosity was also recorded. It is pointed out that the work is particularly relevant to the practical problem of subsoil pavement stabilization in which the terpolymer acts as a soil binder. Suggestions on further work are given.The authors would like to acknowledge the Qatar National Research Fund (a member of the Qatar Foundation) for their support under the NPRP award [NPRP 5-508-2-204]

Subgrade soil stabilization using ionic polymer variants

his study evaluates the potential applications of designated variant ionic polymeric pavement subgrade binders. The polymer binders such as anionic and cationic variants were synthesized and confirmed by physico-chemical characterization techniques. These binders were then applied to two types of soils. The effectiveness of stabilization was evaluated based on the data from standard mechanical tests such as compressive strengths and toughness. In general, the results revealed that application of an ionic moduli binder can improve properties of the subgrade. The strengthening of the soil was attributed to charge neutralization and hydrogen bonding while better dispersions of binders resulted in enhanced toughness and strength. Scanning electron microscopy also confirmed the soil and polymer networks

Co-polymer soil subgrade binders

This invention is in the field of road construction as it relates to improving the quality and lifetime of asphalt roads and pavement surfaces. The invention relates to methods and compositions utilizing co-polymers in combination with soil to form improved subgrade soil binder compositions for supporting asphalt roads and pavement surfaces.U

Co-polymer soil subgrade binders

This invention is in the field of road construction as it relates to improving the quality and lifetime of asphalt roads and pavement surfaces. The invention relates to methods and compositions utilizing co-polymers in combination with soil to form improved subgrade soil binder compositions for supporting asphalt roads and pavement surfaces.U

Co-polymer soil subgrade binders

This invention is in the field of road construction as it relates to improving the quality and lifetime of asphalt roads and pavement surfaces. The invention relates to methods and compositions utilizing co-polymers in combination with soil to form improved subgrade soil binder compositions for supporting asphalt roads and pavement surfaces.U