Sorptivity Values Research Articles

Finer Measurement Scales for Induced Hydrophobicity Using the Water Droplet Penetration Test

The Water Droplet Penetration Test (WDPT) is commonly used in most soil water repellency (SWR) research and is particularly prominent in field studies after wildfire events. Suppose a water droplet does not infiltrate the soil within the first five seconds. This soil is considered to contain some degree of water repellency, classified by the overall penetration time. Our results show an inflection point in the plot of the height of a droplet vs. droplet penetration time during a WDPT trial. This inflection point is indicative of a combination of two possible flow patterns influencing droplet penetration, one governing and the other—caused by particle lift—drastically impeding the infiltration rate. The reorganization of the intrinsic particle lift at the air–water interface leads to contact angles hindering the expected penetration, delaying the expected infiltration rate to degrees larger than a continuously flat porous hydrophobic surface would. The particle lift creates an instability that can create two competing regimes, leading to two sets of water droplet penetration times. The similarity among sorptivity values for coarse grains at higher hydrophobicity levels, medium grains at intermediate hydrophobicity levels, and fine grains at lower hydrophobicity levels suggests that interpretation of the WDPT needs to be adjusted based on grain size.

Optimizing the compressive strength of low-grade hydrous clay and copper slag‐based sustainable ternary blended geopolymer mortar

Ternary blended geopolymers represent a new class of sustainable binders with improved properties when compared to mono and binary blended geopolymers under ambient conditions. The study focuses on low grade industrial waste materials; locally sourced hydrous clay (HC) waste and copper slag (CS), to create novel Ternary Blended Geopolymer Mortars (TBGM). The addition of CS had a positive effect on strength development. The incorporation of 40 % CS as fine aggregate replacement, improved the proportion of HC in precursors from 10 % to 30 %. The design parameters considered were sodium silicate to sodium hydroxide solution ratio (SS/SH) at (2,2.5,3), the alkaline solution (AL) to binder (B) material ratio (AL/B) at (0.35,0.4,0.45), and the molarity of the sodium hydroxide solution (M) at (8,10,12) respectively. Box Behnken Design (BBD) with response surface methodology (RSM) was used to reduce the number of trial experiments to 15 from a total of 27 and, to statistically optimize and evaluate the interactions of SS/SH, AL/B, and M on the performance of TBGM. The compressive strength of 72 N/mm2 at the SS/SH, M and AL/B as 2.5, 12 and 0.4, respectively, was in good agreement with the experimental result of 78 N/mm2 at similar proportions. From the diagnostics and response plots of RSM, it can be inferred that the molarity of NaOH and AL/B and its combined interaction had more critical influence on the compressive strength of TBGM compared to SS to SH ratio. The microstructural and durability investigation further validated the optimization studies, as the optimum mortar specimen exhibited a denser microstructure with reduced shrinkage and sorptivity values.

The driving force of water absorption in cementitious materials: An analysis of surface-free energies and pore structure

Upon the initial contact of hydrophilic cementitious materials with water, capillary absorption becomes the dominant phenomenon leading to durability deterioration of structures. The water absorption characteristics of such materials are governed by the interplay between pore structure and surface-free energies, with the latter being a factor often overlooked. In this study, advanced inverse gas chromatography (IGC) measurement techniques were employed to investigate the one-dimensional capillary water absorption of ordinary Portland cement (OPC) and alkali-activated slag (AAS). Results revealed water sorptivity values for OPC, AAS(NaOH), and AAS(Waterglass) as 0.0112, 0.0137, and 0.0187 mm/s0.5, respectively. This phenomenon can be attributed to the higher total surface-free energies observed at the liquid-solid interface in AAS materials, measuring 100.10 and 119.56 mJ/m2, compared with 74.25 mJ/m2 for OPC, consequently increasing capillary pressures. Moreover, it is observed that OPC exhibited a more complex pore tortuosity in comparison to AAS. This study underscores the dual role played by both capillary pressures and pore tortuosity in determining the water absorption characteristics of cementitious materials.

Impact of manufactured sand and sintered fly ash aggregate on the mechanical and durability characteristics of normal-strength soncrete

This study examined the impact of substituting Natural Coarse Aggregate (NCA) with varying quantities of sintered fly ash aggregate (SFA) in concrete. To ensure sustainability, manufactured sand (M-Sand) was consistently substituted for river sand in all mixtures. Slump values increased as the SFA content increased, which positively impacted workability. The results suggest that a complete replacement of the coarse aggregates can achieve substantial weight reduction potential. Even though compressive strength, split tensile strength, flexural strength, and Young's modulus decreased as the SFA content increased, all compositions (SFA0, SFA50, and SFA100) surpassed the minimum field requirement of 20 MPa compressive strength. Impact testing adversely affected the impact strength of the SFA50 mix, while SFA0 and SFA100 demonstrated comparable failure modes. It is important to note that replacing 50% NCA with SFA resulted in an increase in concrete durability, as demonstrated by a lower average sorptivity value. The results of this study indicate that SFA is a potential partial replacement for NCA. It provides advantages in terms of workability, weight reduction, and potential enhanced durability, while still maintaining adequate strength for field applications.

Mechanical, freeze-thaw, and sorptivity properties of mortars prepared with different cement types and waste marble powder

The cement production process contributes significantly to CO2 gas emissions and environ- mental pollution. To reduce this adverse effect, the substitution of waste marble powder as a cement additive was investigated. In this study, the properties of mortar specimens were analyzed by using waste marble powder as a partial substitute for three different cement types: CEM I 42.5R Ordinary Portland Cement (OPC), CEM II/B-L 42.5R White Cement (WC) and CA-40 Calcium Aluminate Cement (CAC). Waste marble powder has been replaced with ce- ment at 5%, 10%, and 15%. The compressive and flexural strength, capillary water absorption, and sorptivity values of the prepared mixtures were determined before and after freezing and thawing. It was carried out after 28 days of water curing on 50 x 50 x 50 mm specimens for compressive strength and 160 x 40 x 40 mm specimens for flexural strength test. Freeze-thaw testing of the mixture samples was conducted according to ASTM C666 Procedure A. Test re- sults showed that the highest compressive strength before freeze-thaw was obtained in calcium aluminate cement-based mortars containing 10% by weight waste marble powder replacement for cement. The appropriate waste marble powder ratio was determined as 10% in all cement types used in the study. Before freeze-thaw, the mechanical properties of CAC-based mixtures were higher than those of other cement types. However, as the number of freeze-thaw cycles increased, the strength losses were more significant compared to OPC and WC.

Assessment of Water Transport and Chemical Attack of Meta-Illite Calcined Clay Blended Cement in High-Performance Concrete.

Rapid urbanisation causes a rise in the need for infrastructure, which in turn fuels the creation of additional concrete and further increases cement supplies. Activation of illite-based clay mineral and usage in concrete production is one of the sustainable ways to address the cement industry anthropogenic issues. This study evaluates the durability properties of water transport (water absorption, and capillary water absorption), and resistance to aggressive environments (5% solutions of hydrochloric acid, HCl; sodium sulphate, Na2SO4; and calcium chloride, CaCl2) of meta-illite calcined clay (MCC)-based high-performance concrete (HPC). For this purpose, concrete was produced with 5, 10, 15, 20, 25 and 30% MCC content in partial substitution of CEM II. Results from the water absorption tests indicate an average percentage value of 3.57%, 3.35% and 2.52% for all the observed mixes at 28, 56 and 90 days, respectively, with MCCC-10 HPC having an average best value of 2.23% across the curing ages. On all observed days, the 5 to 15% cement replacements had very close average water sorptivity value of 0.125 ± 0.001 mm/min0.5 with the control mix (0.113 ± 0.011 mm/min0.5). The aggressive environments exposure findings of the hardened MCC-based HPC specimens of 10 to 20% recorded an approximately 15% compressive strength loss in HCl, Na2SO4 and CaCl2 solutions over the 90 days of curing. In all, the HPC mixes of 5 to 15% MCC content obtained an average durability performance factor of 89%. As a result, these findings imply that MCC can replace cement in up to 15% of HPC production.

Comparison of Soil Hydraulic Properties Estimated by Steady- and Unsteady-Flow Methods in the Laboratory

In this study, soil hydraulic conductivity (K) and soil sorptivity (S) values estimated by applying various steady- and unsteady-flow methods using cumulative infiltration data of three disturbed soils (sandy loam, loam, clay) obtained from a disc infiltrometer in the laboratory at various negative pressure heads were compared. The steady-flow methods used were those of Ankeny et al. and Reynolds and Elrick as well as Logsdon and Jaynes, while the unsteady-flow methods were those of Haverkamp et al. (two-term (2T) and three-term (3T) infiltration equations) and Zhang. The method of White et al., which is a steady-flow method but also uses unsteady-flow infiltration data, was also examined. The results showed that the three steady-flow methods, as well as the Zhang equation, for values of the van Genuchten coefficient n > 1.35, tend to give similar values of K. The 2T infiltration equation with β = 0.6 provided hydraulic conductivity values greater than those estimated by the steady-state methods but gave negative K values in some cases. The values of the coefficients C1 and C2 of the 2T equation were affected by the infiltration time. The coefficient C1 increased while C2 decreased with increasing time when the cumulative linearization method (CL) was applied, but the change in C1 tended to be smaller than that in C2. The inverse solution of the 3T equation using the Excel Solver application for β = 0.75 and β = 1.6, when positive values of K were obtained, approached better the K values estimated by the steady-flow methods compared with those estimated using β = 0.6. Regarding the estimation of S from the unsteady-flow equations (2T, 3T, Zhang), comparable S values were obtained by all equations. The differences between the S values of the various methods are smaller compared to those of K, and S is less affected than K in terms of time. The problem of negative estimates of K might be attributed to the fact that the soils used in this study are classified as soils situated in the domain of lateral capillarity or are not completely homogeneous or soil compaction is observed at some depth. In the case where the soils are not completely homogeneous, the Sequential Infiltration Analysis (SIA) method with β = 0.75 corresponding to the soil types studied was proved to be effective in estimating K values.

Potential improvement of clinker sand in the mechanical high temperature and transport properties with GGBS-based prepacked geopolymer composite

In this study, a new generation prepacked geopolymer composite (PGC) material that can meet different needs was obtained by combining geopolymer concrete (GPC) and prepacked aggregate concrete (PAC) technology. In the production of PGC, 5-8 mm quartz aggregates were placed in molds and, geopolymer mortar was injected between these aggregates. Aluminosilicate based blast furnace slag (GBFS) was used as binding in geopolymer mortars; sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) was used as alkali activator. In addition, clinker aggregate in different proportions was used as fine aggregate (0–4 mm) in the production of mortar. Within the scope of the study, the physical, mechanical, permeability and high temperature resistance properties of PGC were investigated. The produced samples were cured at 30 and 60 °C for 6 and 8 hours. Hardened unit weights of PGC vary between 2342 and 2539 kg/m3, and sorptivity values vary between 0 and 0.04 kg/m2.min0.5. While the increase in curing temperature and curing time increases the hardened unit weight values, it decreased permeability values. While the increase of clinker aggregate in the mortar phase does not change the hardened unit weight, it significantly reduced permeability. When the PGC samples are cured at 30 °C, the compressive strengths are 20.38–39.03 MPa; when curing at 60 °C, the compressive strengths are 35.21–57.04 MPa. Flexural strengths, 2.35–6.96 MPa with 30 °C cure, achieved 4.27–9.93 MPa results with 60 °C curing. Increasing the curing time and curing temperature significantly increased the compressive and flexural strengths. The increase in the amount of clinker aggregate added to the mortar phase decreased the strength values. While the compressive strength values of PGC mixtures do not fall below 15 MPa after being exposed to 300 °C high temperature; after the application of 600 °C high temperature, it lost up to 70% of its strength. Increasing the curing time and curing temperature, increased the high temperature resistance. The increase in the amount of clinker aggregate in the mixtures, decreased the strength loss rate.

Sorptivity Analysis of Lightweight Concrete Based on Fly Ash and Bottom Ash

Lightweight concrete has a density lower than conventional concrete, which ranges between 1,400-1,800 Kg/cm3. The use of lightweight concrete as a more sustainable construction material continues to be developed to reduce the weight of the building. Fly ash as a residue from coal combustion has a high SiO2 content as a cement substitute. Bottom ash with a light density can also be used as a substitute for fine aggregate. Sorptivity test in lightweight concrete aims to determine concrete's ability to absorb water and how the pores in concrete behave. Sorptivity testing was carried out by a 5x5x5(cm3) mortar sample that was immersed in water. Then the mortar was weighed based on time intervals of 1, 5, 10, 20, 30, and 60 minutes, then continued for 2, 3, 4, 5, and 6 hours and 1, 2, 3, 4, 5, 6, 7, and 8 days. The results showed that the use of fly ash and bottom ash could increase the sorptivity value in the mortar up to 0.45%, where the function of the fly ash and bottom ash is to fill the pores in the mortar so that the water content that seeps into the mortar is reduced. Thus, the use of fly ash and bottom ash to support ecologically friendly and lighter building results in more sustainable material properties.

Pengaruh Binder Akrilik terhadap Sifat Fisik dan Mekanik Mortar Polimer

Initial damage to the structure occurs in the outer layers of the affected surface exposure to the peat environment and the static and dynamic movement of the structure. To prevent structural damage, the latest technological innovations are needed in the use of mortar constituent materials to increase the strength of the mortar. Polymer mortar is a composite material formed from a mixture of fine aggregates, cement, water and polymer binders or binders with a certain level. The purpose of this study is to determine the effect of the use of acrylic binders on the physical and mechanical properties of polymer mortars and the influence of peat water on the future of the mortar. The substitution of acrylic binders with water consists of 3 substitutions, namely 20%, 30% and 40% and 0% as controls. The results of the search for acrylic binders on the mortar mixture obtained a minimum physical property value at 30% acrylic use in the 28-day test, namely. The porosity value of the mortar is 9.80%, the waterabsorption value of the mortar is 4.67% and 4.72%, and the sorptivity value of the mortar is 0.70. From the value of physical properties obtained the degree of tightness of the polymer mortar well with the use of acrylic binders in the mixture. For the mechanical properties of polymer mortar, compressive strength testing is carried out with optimum compressive strength at the use of 30% acrylic. The value of the compressive strength of the mortar is 33 Mpa.

Durability performance of concrete containing recycled coarse aggregates derived from laboratory-tested specimens

PurposeThe durability of concrete containing recycled aggregates, sourced from concrete specimens that have been tested in laboratory testing facilities, remains understudied. This paper aims to present the results of experiments investigating the effect of incorporating such type of concrete waste on the strength and durability-related properties of concrete.Design/methodology/approachA total of 77 concrete cylinders sized Ø100 × 200 mm with varying amount of recycled concrete aggregate (RCA) (0%–100% by volume, at 25% increments) and maximum aggregate size (12.5, 19.0 and 25.0 mm) were fabricated and tested for slump, compressive strength, sorptivity and electrical resistivity. Disk-shaped specimens, 50-mm thick, were cut from the original cylinders for sorptivity and resistivity tests. Analysis of variance and post hoc test were conducted to detect statistical variability among the data.FindingsCompared to regular concrete, a reduction of slump (by 18.6%), strength (15.1%), secondary sorptivity (31.5%) and resistivity (17.0%) were observed from concrete containing 100% RCA. Statistical analyses indicate that these differences are significant. In general, an aggregate size of 19 mm was found to produce the optimum value of slump, compressive strength and sorptivity in regular and RCA-added concrete.Originality/valueThe results of this study suggest that comparable properties of normal concrete were still achieved by replacing 25% of coarse aggregate volume with 19-mm RCA, which was processed from laboratory-tested concrete samples. Therefore, such material can be considered as a potential and sustainable alternative to crushed gravel for use in light or nonstructural concrete construction.

Optimization of without SCM concrete exposed to seawater according to minimum cost and CO2 emissions: Sustainable design with ABC algorithm

The service life of marine concrete structures is relatively shorter due to various salts in seawater. In this context, assistance is obtained from the exposure classes in standards such as EN 206. In this study, an ABC-based (artificial bee colony) algorithm was developed that considers the CO2 emissions and cost analysis of concrete designed according to EN 206 standards. The number of studies involving algorithms in designs according to regulations and standards is very few in the literature. In addition, Supplementary Cementitious Materials (SCMs) are generally used in concretes exposed to sea water. This study investigated the physical, mechanical, durability, microstructure, cost and sustainability properties of concretes without SCM. This study produced nine concrete mixes with different cement dosages (260–300–340 kg/m3) and a water/cement ratio (0.45,0.55, and 0.65). The mixes were cured in normal water (NWC) and seawater (SWC). As the cement mixes’ cement dosage increased, the water absorption and apparent porosity values decreased. Since the increase in the w/c ratio increased the capillary void content of the mixes, it enhanced the porosity and sorptivity values. While the 28d compressive strength of NWC-applied concretes varies between 31.3 and 39.8 MPa, the compressive strength of SWC-applied concrete varies between 30.7 and 36.8 MPa. After 80 wetting-drying cycles, the compressive strength of the concretes decreased below 20 MPa. The CO2 emission values of the concrete vary between 270 and 343 kg and their costs range between 17.9 and 21.5 $/m3. According to the ABC algorithm, it was determined that cement dosage should be 260 kg/m3, w/c ratio should be 0.45 for high compressive strength, low cost, and CO2 emission. As a result, it has been determined that a lower cost and more durable concrete design can be made if methods such as the ABC algorithm are combined with EN 206 standards.

Effect of washing aggregate sludge waste on the properties of alkali-activated blast furnace slag

The growing production of aggregates in quarries leads to the generation of solid wastes and an expansion of energy footprint. Since these solid wastes are generally stored in landfills, they cause environmental and economic problems. This paper sought to provide a sustainable alternative for the valorization processes of one of these solid wastes, washing aggregate sludge (WS) obtained from a specific aggregate quarry, by investigating the possibility of its utilization as a supplementary precursor material in alkali-activated paste and mortars. The mixtures were produced by replacing the blast furnace slag (BFS) with WS by 0, 25, 50, and 75 wt%, and the effect of WS on the physical, mechanical, durability, and microstructural properties of samples was comprehensively studied. The results revealed that the incorporation of WS consistently extended the setting time of mixes, providing a suitable setting time range for ease of handling, and the setting time of mixtures was predominantly influenced by the initial SiO2/Al2O3 molar ratio. The mechanical and physical test results indicated that the increase in WS replacement ratios increased the water absorption, voids content, drying shrinkage, and sorptivity values, and reduced the compressive strength of alkali-activated mortar samples. On the other hand, an increase in WS ratio efficiently increased the residual compressive strength values of mortar specimens during wetting-drying cycles, indicating its suitability for warm and moist climatic areas. The microstructure analysis revealed that C-A-S-H type gels were mainly formed in the reference mix (100% BFS), whereas N-A-S-H along with C-A-S-H type gels were detected in the specimens produced with a higher WS ratio. The incorporation of WS up to 25% to produce BFS-based AAM as a construction material can be a competent method to efficiently utilize WS waste which may also protect the environment and ensure sustainability.

Durability performance and microstructure analysis of nano engineered blended concrete

In the present study, the performance of the nano engineered blended concrete was evaluated for the durability performance by conducting Rapid Chloride Penetration test, water absorption and sorptivity which represent the measure of water penetration through the matrix when exposed to aggressive agents present in the environment. All the formulated mixes of blended concrete bearing vetrified tiles powder, silica fume and fly ash with and without nano reinforcement were tested and analysed at 28, 56 and 91 day curing periods. The dosage rate of the Carbon Nano Tubes varied from 0.01% to 0.1% by weight of the binder. From the analysed results, the mix with 0.05% of the Carbon Nano Tubes present by weight of the cementitious materials exhibited noticeably less water absorption value of less than 3%, less sorptivity value and very less I value obtained from the Rapid Chloride penetration test. The SEM-EDS analysis was carried out to determine the morphology of the matrix and the intensities of the crystalline phases formed, was determined by XRD analysis. From the analysis carried out, it was observed that the mix with 0.05% of the addition of Carbon Nano Tubes serves to be the optimum mix. The same mix has also proven to be highly durable which can be implemented as a engineering concrete to be used in harsh environments.

Effect of microplastics on silty loam soil properties and radish growth

Abstract Microplastics (particles of plastics <5 mm) affect the physical, biological and hydrological properties of agricultural soil, as well as crop growth. We investigated the effect of the addition of three microplastics (high-density polyethylene (HDPE), polyvinyl chloride (PVC), and polystyrene (PS)) at a concentration of 5% (w/w) to a silty loam soil on selected soil properties and growth of radish (Raphanus sativus L. var. sativus). Changes in the soil properties and radish growth in three microplastic treatments were compared with the control. Soil properties (bulk density, hydraulic conductivity, sorptivity, water repellency) were estimated for each treatment at the beginning and at the end of the radish growing period (GP). The bulk density was significantly lower in the HDPE and PVC treatments compared to the control within the measurement at the beginning of the GP and in all microplastic treatments compared to the control at the end of the GP. The values of hydraulic conductivity and water sorptivity did not show significant differences between any treatments within the measurement at the beginning of GP, but they were significantly higher in the HDPE treatment compared to the control at the end of the GP. The growth of radish was characterized by the plant biomass and effective quantum yield of Photosystem II (Y (II)). We did not find a statistically significant difference in the total biomass of radish between any of the experimental treatments, maybe due to used concentration of microplastics. The mean value of Y (II) was significantly higher in all microplastic treatments compared to control only within the last measurement at the end of the GP. A statistically significant change of Y(II) in all microplastic treatments may indicate functional shift in soil properties; however, the measured values of the soil characteristics have not shown the significant changes (except for the bulk density values in all microplastic treatments and hydraulic conductivity together with sorptivity in HDPE treatment within the measurement at the end of GP).

Performance of glass powder substituted slag based geopolymer concretes under high temperature

Geopolymer concretes provide advantages in terms of recycling waste materials. Geopolymer concretes are advantageous in terms of both limiting the use of Portland cement and recycling waste materials. In this study, 5 different geopolymer concrete mixture groups were prepared by replacing slag with 0.5%, 10, 15 and 20% by weight glass powder (GP). Geopolymer concrete samples prepared by using 12 M sodium hydroxide solution as an alkali activator were cured in the laboratory environment. The samples, which completed their curing periods, were kept at 150, 300, 450, 600 and 750 °C temperatures for 1 h. Compressive strength, weight change and sorptivity values of these samples were determined. These results were interpreted together with the visual inspections and microstructure analyzes (SEM and EDS) of the samples. As the GP substitution rate increased, the mechanical properties of geopolymer concretes decreased. However, GP improved the performance of geopolymer concretes exposed to high temperatures. Cooling in air affected the samples less negatively than cooling in water. While the Ca/Si ratios of the samples decreased at 450 °C and above, the Si/Al ratio increased.

Assessment of Contamination Management Caused by Copper and Zinc Cations Leaching and Their Impact on the Hydraulic Properties of a Sandy and a Loamy Clay Soil

Soil hydraulic properties are crucial to agriculture and water management and depend on soil structure. The impact of Cu and Zn cations on the hydraulic properties of sandy and loamy clay soil samples of Central Greece, was investigated in the present study. Metal solutions with increased concentrations were used to contaminate the soil samples and the effect on hydraulic properties was evaluated, demonstrating the innovation of the current study. The soil samples were packed separately into transparent columns and the initial values of hydraulic conductivity, cumulative infiltration, infiltration rate and sorptivity were estimated. In order to evaluate soil adsorption, metal concentrations were measured at the water leachate. After the contamination of the soil samples, the hydraulic properties under investigation were determined again, using distilled water as the incoming fluid; the differences at the hydraulic parameters were observed. After doubling metal concentrations into the incoming solution of loamy clay soil, metal adsorption and the values of the hydraulic parameters increased significantly. Loamy clay soil showed interaction between the clay particles and the positive charge in the incoming fluid, which led to a possible increase in aggregation. Furthermore, aggregation may led to pore generation. Contamination of sandy soil exhibited no impact on aggregation and soil structure. In order to evaluate the differences on the hydraulic properties and soil structure, the experimental points were approximated with two infiltration models.

MECHANICAL PROPERTIES AND FRACTURE PREDICTION OF CONCRETES CONTAINING OIL PALM SHELL AND EXPANDED CLAY FOR FULL REPLACEMENT OF CONVENTIONAL AGGREGATES

In order to reduce the continual depletion and exploitation of natural resources, this paper examines the mechanical properties and fracture prediction of sustainable lightweight aggregates concretes comprising agro-industrial waste or/and artificial aggregate, considering a full replacement of conventional coarse aggregate. The fresh and hardened properties are examined, from which three out of the five design mixes can achieve structural concrete specifications. It is observed that compression, tensile, and flexural strengths of the mixes exhibit a similar behaviour trend, as relatively higher values can be obtained from homogenous coarse aggregates compared to heterogeneous aggregates for different proportions of oil palm shell (OPS) and expanded clay replacement. The experimental results showed compression strength of 13 to 32 MPa, splitting tensile strength of 1.32 to 2.97 MPa and flexural strength of 1.67 to 5.24 MPa for the investigated mixes at concrete age of 28 day. Most of the mixes able to achieve structural use. Amongst the mixes, those containing expanded clay lowered the corresponding sorptivity values. Although statistics prove that the prediction models of tensile and flexural strengths can represent existing experimental findings, further investigations are recommended for a better properties forecasting of lightweight aggregate concrete containing OPS and expanded clay.

Lightweight masonry block without Portland cement

ABSTRACT Huge amounts of fly ash - a substance that does not conform to the ASTM C618 classification due to its chemical properties - have been abandoned in landfills around the world, despite their self-cementing property. It has not been used in concrete making applications due to its large amounts of free lime and sulfate contents. The fly ash in these plants is dumped in landfills, causing serious environmental hazards. Fly ash is disposed to the landfills by belt conveyors after being humidified with water. Therefore, the fly ashes humidified in the landfill areas are hydrated in nature. This hydration is further intensified in landfills by rain and snow. Thus, the free lime content of fly ash decreases due to its long hydration process. In this work, the lightweight masonry blocks were produced by mixing normal and hydrated fly ashes or normal, hydrated fly ash and lime without Portland cement. The compressive strength, water absorption, sorptivity, density, porosity, and thermal conductivity values of the samples produced were determined. The results obtained from these tests showed that lightweight masonry blocks could be produced by using these waste materials in building applications.

Haverkamp Modelin 4 Terimli Uzantısını Kullanılarak Teras Zeminin Doygun Hidrolik İletkenlik ve Sorptivite Tayini

Uzunçayır water retention Dam is located in the Tunceli province. This semi-arid mountainous region in eastern Turkey is prone to erosion. To combat this phenomenon, terraces along the edge of the Munzur University campus were built on sloping ground with pine plantations. The objective is twofold, on the one hand to mitigate soil erosion and protect the dam from sediments deposits, and on the other hand to promote the infiltration of rainwater and the vegetation of the sloping soil. However, the so-called ecofunctions of the terraces over the time are not proven. Monitoring the infiltration capacities of the terraces over time and space will allow a better understanding of their contribution to the hydrology of the watershed and their effect on soil erosion. The Beerkan infiltration technique offers simple and inexpensive experimental protocols. In addition, treatment methods are constantly improving. More recently, the four-term expansion of the implicit Haverkamp cumulative infiltration equation has been proposed. This complicated but robust formulation was used in this study to estimate the soil sorptivity S and saturated hydraulic conductivity Ks of terrace soil at Tunceli. The average Ks value of studied site was estimated to be 0.0852 mm/s with a standard deviation of 0.0112 mm/s. The soil sorptivity values were more extensive with mean value of 2.1227 mm/s0.5 and a standard deviation of 0.5855 mm/s0.5. The fit of the model used was perfect, showing that fast and robust estimation of S and Ks are possible using the new model.