Total Water Absorption Research Articles

Water transport mechanisms in concretes bearing mixed recycled aggregates

Aggressive agents present in the environment that penetrate concrete through its pore structure induce deterioration, compromising the service life of concrete members. Determining the viability of using recycled materials in structural concrete calls for a prior understanding of their effect on water transport, the primary vehicle for external agent ingress. This article describes durability indicators such as electrical resistivity, water permeability (pressure testing), total water absorption, effective porosity and sorptivity that directly or indirectly measure water penetration and consequently performance across the service life of concrete bearing 20% to 100% mixed recycled aggregate (MRA). The 28 d concretes studied here with up to 75% MRA exhibited <7% weight gain due to water absorption, <15 vol% porosity and <30 mm maximum depth of water penetration under pressure, all indicative of high quality concrete. In 90 d materials, the values of the aforementioned parameters were 40% lower. Even in concrete with up to 100% MRA (with 28 d readings of 50 Ω m to 100 Ω m), electrical resistivity remained unaffected, The present findings reveal that high quality high durability structural concrete can be viably manufactured with up to 75% MRA.

Water Absorption Properties of Geopolymer Foam after Being Impregnated with Hydrophobic Agents.

Geopolymer foam is classified as a lightweight material with high porous in its matrix which has great offer for applications requiring fire-resistant, thermal, and acoustic properties. However, the high sensitivity to humid environments can be a major barrier of geopolymer foam that limits the variety of applications of this material. Based on this drawback, two types of hydrophobic agent (Lukosil M130 and Lukofob ELX) were used as an impregnator to treat the surface of geopolymer foam samples. This paper presented the results of water absorption properties of the untreated and treated geopolymer foam composites. The obtained properties were flexural strength, compressive strength, density, total water absorption, the rate of water absorption, and water absorption coefficient. The results showed that the samples after being impregnated with hydrophobic agents improved significantly their waterproof property especially using Lukosil M130. Moreover, the samples treated with Lukosil M130 had positive impact on their mechanical strength.

Properties of self-compacting mortar containing nano cement kiln dust

Abstract Micro voids inside the cementitious materials mortar matrix drastically reduce the load carrying capacity of the mortar. Furthermore, the weak interface between the aggregate and mortar will promote the micro cracks initiation and cracks propagation. In this study, a nano cement kiln dust was added to the self-compacting mortar to enhances the microstructure of mortar and reduce the micro voids effectiveness. Nano cement kiln dust was prepared and used as additives to the self-compacting mortar in 1, 2, 3, 4, 5 wt.% to be used as cementitious sustainable materials. Cement kiln dust was prepared by grinding process until achieving to nano particle size, nano particle size was provided and checked by AFM and FESEM tests. Some self-compacting mortar properties was tested at 7, 28, and 90 days’ age. Fresh properties of the self-compacting mortar were evaluated by using mini flow table test and mini v-funnel test. The experimental results of self-compacting mortar shown that the mechanical properties which includes the compressive strength, direct tensile strength and flexural strength were increased as nano powder percentage increases. The physical properties such as porosity and total water absorption was decreased with the increase of nano powder contents. Dry density of the self-compacting mortar increased as nano powder percentage increase. The microstructure homogeneity and nano powder distributions of self-compacting mortar were explained by using FESEM images.

Mechanical and physical properties of stabilised compressed coal bottom ash blocks with inclusion of lateritic soils in Niger

Abstract This paper describes the results from an investigation on the production of compressed block made with coal combustion by-products and local clayey soil in Niger. Stabilisation with Portland cement and a mixture of Portland cement and lime was adopted. Mechanical, physical, hydric, and thermal characterisation of the produced bricks was carried out. Blocks with satisfactory compressive strength were produced, with samples consistently exceeding the compressive strength of 4 MPa. Stabilisation with Portland cement proved to be the most effective in terms of strength development. However, satisfactory results were obtained with partial substitution of cement with lime (up to 30%). Porosity was found to be in the range 33% to 40% for all samples. The low thermal conductivity (in the range 0.31 to 0.48 W/m·K) was presumably influenced by the high porosity. Water absorption of the bricks was found to be very fast, although total water absorption (in the range 20.6 to 28.7%) was lower than the calculated porosity, suggesting that some of the pores were not accessible by water. Samples subjected to heating showed very promising results in terms of strength and mass loss. An increase in compressive strength was recorded up to temperatures of 400 °C. This might be due to the triggering of other reactions in the binding matrix due to the chemistry of the bottom ash. A change in colour of samples (from grey to red) was observed, due to the dehydroxilation of iron hydroxide turning into ferric oxide.

Effect of graphite particles on physical and mechanical properties of nickel matrix composite

The composite materials have effective properties and characteristics for use in most modern and important applications such as space and transportation applications, especially in internal combustion engines as well as applications and marine industries. In this study, Nickel – 5 vol.% Zirconium dioxide composites with 0, 2, 4, 6 and 8 vol. % of graphite particles are prepared by powder metallurgy technique. The samples are pressed at 900 MPa for 1 min after mixing the hybrid composite powders for 15 min by using a mechanical mixer, followed by sintering at 1160 oC for 3 hours. The hybrid composites are characterized by using an optical microscope. The wear test under dry sliding conditions was performed under various loads of 5, 10, 15 and 20 Newton and at a fixed sliding distance of around 1810 m. It is found that increasing graphite content results decrease in bulk and apparent densities in contrast with total porosity, apparent porosity, and water absorption. Alternatively, the increasing volume fraction of graphite particles improves the micro-hardness, diametral compressive strength and wear resistance till an optimum value up to 4 %, then severely reduction is observed. Whereas the wear resistance decreased by increasing the applied loads for all reinforcement content. The results, in conclusion, reveal that the hybrid composites at 4 % graphite particles relatively have high mechanical and wear properties, and it could be considered a suitable because of high corrosion resistance in our daily life applications.

Analysis of the improved water-resistant properties of plaster compounds with the addition of plastic waste

The aim of this article is to analyse the water-resistant properties of gypsum compounds with plastic cable waste added in order to determine the suitability of their use as an alternative to combat moisture problems in buildings. In the experimental process, test samples were made and subjected to capillary water absorption, water vapour permeability, wet chamber, water-stove cycle and total water absorption tests, and their porosimetry was also studied using the mercury porosimetry test. The results showed a significant decrease in water absorption and retention capacity. This is due in part to the reduced pore volume of the compounds that is achieved without affecting the hygrothermal properties of the gypsum products and keeping their mechanical properties above the minimum values indicated in the regulations. Thus, the material studied is a good alternative to the gypsums currently available on the market to be applied in the areas of buildings most exposed to water and it contributes to reduce environmental impacts.

The effects of calcium stearate on mechanical and durability aspects of self-consolidating concretes incorporating silica fume/natural zeolite

Moisture and aggressive ions transfer into concrete can be considered a significant threat to the durability of self-consolidating concretes (SCCs). To restrict moisture and aggressive ions transfer into concrete, utilizing damp-proofing agents is expected to be beneficial. These admixtures can decrease permeability of concrete, especially the permeability under non-hydrostatic condition, by providing a water-repellent layer along the capillary pores. This study investigated the impacts of calcium stearate (CS), as a damp-proofing agent, on durability properties of SCCs which were prepared with various types of supplementary cementitious materials (SCMs). In addition to durability properties, the effects of CS on mechanical characteristics and properties of fresh concrete, and microstructure have been studied as well. The outcomes demonstrated that in fresh concrete, CS (up to 7 kg/m3) prompted a decrease in workability and density of fresh concrete without any significant impact on slump loss. The results of hardened concrete evaluation also showed a reduction in either density of hardened concrete or compressive strength. Plus, microstructure analysis showed that incorporation of CS deteriorates both the cement paste and the interfacial transient zone. Eventually, although CS had a negligible impact on electrical resistivity, total water absorption, and chloride diffusivity, it was absolutely effective on permeability of concrete under non-hydro static pressure. In this regard, inclusion of CS drastically reduced the depth of capillary penetration of water in addition to short and long term water absorption. As a case in point, incorporation of 7 kg/m3 of CS decreased the last-mentioned parameters by respectively 60%, 72%, and 40% compared to the reference mixture after 120 days of moist curing.

Water transport in binary eco-cements containing coal mining waste

This study explores certain indirect, water transport-related durability indicators for mortars made with cement in which 20% or 50% of the ordinary portland cement (OPC) is replaced by thermally activated coal mining waste (ACMW). The valorisation of ACMW is triply beneficial, environmentally speaking, for it reduces waste stockpiling and its processing emits less CO2 and requires less fossil fuel-based energy than OPC manufacture. Its addition was observed to generate a finer pore structure and a larger volume of pores accessible to water. In mortars with 50% ACMW, pore volume rose by approximately 30%, lowering density and consequently mechanical strength. Total water absorption declined by 13% and capillary absorption by 24% in mortars with 20% ACMW, whilst no significant variations in either parameter relative to the OPC reference were found in the materials with 50% replacement ratios. Permeability to water penetration under pressure rose substantially in both blended mortars, although as the maximum and mean depth values lay within the limits specified in Spain's structural concrete code, the materials would be classified as impermeable. The mortars with 20% replacement exhibited no greater drying shrinkage than the OPC materials, whereas the mortars bearing 50% ACMW shrank by approximately 50% more than the reference.

Durability and mechanical properties of precast concrete curb containing waste copper slag

Copper slag is a by-product which has been widely used in several industries. After being used for abrasive tools, it is discarded in the environment where it can have a harmful impact. The size of copper slag particles ranges up to a diameter of 3 mm, and is of a relatively similar size to fine sand, for which it could therefore be substituted in the production of precast concrete curbing. To this aim, the strength and the durability of curbing were evaluated through a series of tests on six different proportions of waste copper slag ranging from 0 to 100% replacement of fine sand. It is concluded that substituting 40% of fine sand with waste copper slag yields the best mechanical and durability properties. By replacing this proportion, the compressive and bending strength of concrete increased by almost 30% and 14%, respectively. However, a slight effect was found in the total water absorption and abrasive resistance. The freeze–thaw resistance of concrete curbs increased significantly after a 20% replacement by waste copper. This study reveals that it is possible to substitute fine sand with waste copper slag without any negative effect on the properties of the curbing.

Retrieving Phytoplankton Size Class from the Absorption Coefficient and Chlorophyll A Concentration Based on Support Vector Machine

The phytoplankton size class (PSC) plays an important role in biogeochemical processes in the ocean. In this study, a regional model of PSCs is proposed to retrieve vertical PSCs from the total minus water absorption coefficient (at-w(λ)) and Chlorophyll a concentration (Chla). The PSC model is developed by first reconstructing phytoplankton absorption and Chla from at-w(λ), and then extracting PSC from them using the support vector machine (SVM). In situ bio-optical data collected in the South China Sea from 2006 to 2013 were used to train the SVM. The proposed PSC model was subsequently validated using an independent PSC dataset from the Northeast South China Sea Cruise in 2015. The results indicate that the PSC model performed better than the three components model, with a value of r2 between 0.35 and 0.66, and the absolute percentage difference between 56% and 181%. On the whole, our PSC model shows a remarkable utility in terms of inferring vertical PSCs from the South China Sea.

POROSITY, PERMEABILITY AND MICROSTRUCTURE OF FOAMED CONCRETE THROUGH SEM IMAGES

This paper examined the foamed concrete (FC) for permeability of total and capillary water absorption, at 28 days of air sealed curing. The microstructure of 15 selected FC specimens was investigated to determine permeability in relation to porosity and density using Scanning Electron Microscopy (SEM) images. The FC specimens of the densities (1100, 1600, and 1800) kg/m3 were made using fine sand and brick aggregates with toner and MK inclusion as additives. The microstructural investigation of the FC revealed, porosity measure as a percentage ratio of the area under investigation to be in the range of (39.65 to 77.7) %. The pore size is in the range of (0.01 to 70) µm, depending on the type of additive, for the mixes containing toner and MK, it is in a fine range of (0.01 to 10.0) µm. For the FC specimens, the finer the pore size, the less permeable and the stronger it is. Permeability is porosity and strength dependent, whereby high porosity leads to high permeability and low compressive strength for FC mixes made with sand or brick only with no additive inclusion. Meanwhile, the FC mixes made with the inclusion of additives, such as the toner and MK20 mixes, showed an evenly spread net of independent air voids with a regular shape within their matrix, which is beneficial in decreasing permeability. Therefore, besides the porosity and strength, the fineness of the pore matrix and the shape factor of the pores are two other key factors in controlling permeability. Toner and MK20 inclusion can enhance the capillary water absorption to reach almost water tight. Besides, MK30 and MK50 inclusion displayed adverse effect on permeability. Depending on the type of filler, the additive, and the percentage ratio of the porosity of the FC matrix at (1600 and 1800) kg/m3 densities, it is possible to produce FC with compressive strength between (55.1 and 30) N/mm2.

Nanomaterials for Consolidation and Protection of Egyptian Faience Form Matteria, Egypt

Egyptian faience is one of the most important archaeological materials that contain a lot of historical and technical information about ancient Egyptian civilization. Unfortunately, the Egyptian faience objects subject to many deterioration factors, especially humidity. Water has a direct role in dissolving the soluble components, it accelerates the physiochemical deterioration processes. In the present study, four types of ready to use nanoproducts were evaluated. It was done to select the best of them to consolidate and protect some archaeological faience from Matteria magazine. The properties of the treated samples, were comparatively investigated by colormetric measurements, static water contact angle, total immersion water absorption, compressive strength, and scanning electron microscope.

Furan resin as potential substitute for phenol-formaldehyde resin in plywood manufacturing

Replacement of phenol-formaldehyde with a mixed furan resin is considered in this work as a means to improving plywood properties made with urea-formaldehyde-based adhesive currently made with an addition of phenol-formaldehyde resin. Previous research showed that the furan resins can improve water resistance and can provide long stability for the glue line. Plywood was manufactured with modified adhesives and characterized in comparison with a reference product. Thickness, physical properties (moisture content, density, and total water absorption), mechanical properties (shearing strength, bending strength, and elasticity modulus in bending), and formaldehyde emission were determined according to standardized methods. The results indicated that the addition of furan resin enhanced the water resistance by 43% and formaldehyde emission is according to E1 class. Also, the mechanical properties were improved; the shear strength for the adhesive composition with furan resin was increased by 14 to 30% compared with the reference product, depending on the testing conditions.

Preparation and characterization of low oil absorption starch via freeze-thawing

The adsorption and structure of freeze-thawed (two rounds) corn (FT-CS), wheat (FT-WS), and tapioca (FT-TS) starches were studied and compared to raw samples. The decrease in total oil absorption of freeze-thawed starches was elaborated. Freeze-thawing increased the total water absorption and slightly increased matrix oil absorption with decreased amylose content. Contact angle (CA), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) showed that the change in groups and the rougher surface correlated with oleophobicity. The decrease in specific surface area via particle size determination increased the oleophobicity. X-ray diffraction (XRD) indicated that all of the samples were A-type with decreased crystallinity of FT starch. This increased the matrix oil absorption. However, the increase in matrix oil absorption has little effect on the decrease of total oil absorption. In summary, freeze-thawing treatment effectively modified the starches and reduced the lipophilicity of the FT starch.

EVALUATION OF A NOVEL PAN BREAD FORMULATED BY WHEAT/MILLET FLOUR DIFFERENT BLENDS

The effect of substituting wheat flour (WF) with different levels (10, 20, 30 and 40%) of millet flour (MF) on rheological properties and pan bread quality were investigated. Substituting WF with MF significantly (p≤0.05) increased protein, fat contents and dough stretching while reduced carbohydrate, wet gluten, dry gluten, all solvent retention capacity parameters, lightness (L*), total color difference (∆E*) value, dough stability and water absorption. No significant (P>0.05) difference was found in physical parameters and overall acceptability of pan bread between control and wheat formulated with up to 10% MF. Generally, the increase in the millet levels caused the increase in the lightness (L*) of crust and crumb color. The crumb L* became lighter (p 0.05) was detected in hardness, springiness, cohesiveness and resilience between control and pan formulated with MF up to 30% (and up to 40% for adhesiveness, gumminess and chewiness). In addition, increasing the storage (at 25oc + 2) time increased significantly (p < 0.05) hardness, gumminess and chewiness.

Supply of water with salinity levels for Morada Nova sheep

The aim of this study was to evaluate the production performance and nutritional state of Morada Nova sheep receiving water containing levels of total dissolved solids (TDS). Thirty-two uncastrated male sheep at an average body weight of 16 ± 1.40 kg were distributed into four treatments (levels of TDS in the drinking water: 640; 3200; 5760; and 8320 mg/L) in a completely randomized design with eight animals per treatment. Performance, intake, apparent nutrient digestibility, water balance, and nitrogen balance were evaluated. The TDS levels in the water did not promote significant alterations in the performance, nutrient intake, or apparent digestibility of the animals. The intake of water supplied in the trough did not show any difference (P>0.05) for the respective treatments, with no interference with the water balance (1.46 kg/animal/day), indicating that the animals kept their water control regular through their physiological mechanisms. Total water intake (1.94 kg/animal/day), water excretion via urine (0.44 kg/animal/day), water excretion via feces (0.03 kg/animal/day), total water output (0.47 kg/animal/day) and water absorption (1.90 kg/animal/day) were not significantly affected by any of the TDS levels in the water. Total nitrogen intake was not significantly affected by the salinity levels, and thus there was no effect on nitrogen balance. The use of water with TDS levels up to 8320 mg/L did not influence the intake, nutrient digestibility, or performance of the animals, only the intake of water provided in the trough. Therefore, water containing high levels of total dissolved solids can be used in the feeding of Morada Nova sheep.

Feasibility of roller compacted concrete pavement containing different fractions of reclaimed asphalt pavement

The present study investigates the optimum fraction of RAP (coarse, fine & total) along with its optimum proportion (50% & 100%) for Roller Compacted Concrete Pavement (RCCP) mixes, based upon various fresh, mechanical and durability properties. The considered properties were optimum moisture content, fresh density, compressive strength, flexural strength, split tensile strength, total permeable voids, water absorption, initial & secondary rate of absorption, and durability properties in aggressive environments of sulfate and chloride ions. Incorporations of any fraction of RAP reduced the fresh properties of the RCCP mixes, however, had less than 4% detrimental effect on the dry density values when compared with the control mix. The compressive strength requirement of 27.6 MPa for RCCP mixes was achieved by all the RAP mixes, except for the mix containing 100% total RAP, however, the same mix achieved the minimum flexural strength benchmark of 3.67 MPa. Additionally, post-failure load carrying capacity of high RAP mixes was observed to be better than the low RAP & control RCCP mixes. Durability results indicated that incorporations of RAP for RCCP mixes could be beneficial, in terms of lower porosity, reduced water absorption, lower initial & secondary rate of capillary water absorption, however, the mixes suffered dramatic losses when subjected to aggressive environments of sulfate and chloride-rich ions. Nevertheless, low proportions of RAP (coarse & fine, separately) may be suggested for these surroundings. Similarly, individual coarse and fine RAP mixes provided with sufficient abrasion resistance depicting their suitability to act as a wearing course of the RCC pavements. Furthermore, incorporation of any fraction of RAP could evidently lower the total production costs of 1 m3 RCCP mix by ∼46% compared to the conventional RCCP mix.

Ceramic properties of Uşak clay in comparison with Ukrainian clay

ABSTRACTIn this contribution, a new raw material, Uşak clay (Usc), was investigated in order to assess its potential for the ceramic industry by comparing it with a world reference ceramic material, a Ukrainian clay (Ukc). Mineralogical characterization (X-ray diffraction [XRD], scanning electron microscopy [SEM] and Fourier-transform infrared [FTIR] spectroscopy), quantitative chemical analysis (X-ray fluorescence [XRF]) and the thermal properties of Ukc and Usc samples were investigated. Additionally, Atterberg limits, particle-size distribution and cation exchange capacity of both samples were determined. Various technological properties of Ukc and Usc were determined in the temperature range 800–1430°C. The bending and compressive strengths, total linear shrinkage, colour, water absorption and unit-volume mass values were measured. The findings from these analyses show that kaolinite-dominated Ukc and quartz-dominated Usc samples differ from each other not only mineralogically, but also in terms of their chemical, physical and technological properties. The firing colour of Usc was determined as 84% white, and so this can be considered as a light firing clay. In addition, due to its low plasticity, Usc may be utilized to reduce both the plasticity of the ceramic materials and the viscosity in slip-casting applied ceramics. Furthermore, the melting temperature of 1300°C suggests that Usc cannot be classified as refractory. However, this property does suggest an economic value for Usc in terms of developing technological characteristics at lower firing temperatures.

Improving the Properties of Clay Brick Using Polyvinyl Alcohol (PVA)

In this study, an experimental research was dedicated to investigate the properties of clay brick treated by polyvinyl alcohol (PVA). Two methods of treatment were conducted. The first contained treating clay brick by submerging the specimens in 1%, 2% and 3% of PVA solution, whereas the second involved coating the brick specimens with 6% PVA (i.e. a high viscous solution). The treated specimens were allowed to dry under ambient temperature in the laboratory before being tested. Standard tests employed for brick specimens were applied. Regarding the specimens treated using the submerging method, results showed that there was a significant contribution of PVA to the compressive strength, total water absorption and efflorescence tests, in which the specimens reached the best performance when PVA was increased to 3%. However, the brick specimens coated by PVA showed a slight increase in the compressive strength, but a noticeable decrease in the water absorption and efflorescence. Â

Viability of peach palm by-product, Spirulina platensis, and spinach for the enrichment of dehydrated soup

Abstract: The objective of this work was to develop dehydrated soup formulations using flour from peach palm by-product (PPB), Spirulina platensis or spinach, as well as to evaluate their composition by physical, chemical, instrumental, and sensory methods. Four formulations were developed: standard, PPB flour, PPB flour and S. platensis, and PPB flour and spinach. The samples were analyzed for proximate composition, chlorophyll content, total phenolic compounds, antioxidant activity, color, viscosity, water absorption, and microbiological parameters. The sensory characterization was performed by the check-all-that-apply method. The soups containing spinach or S. platensis presented the highest protein contents of 3.3 and 4.6 g 100 g-1, respectively. The soups formulated with the microalgae S. platensis showed higher contents of fibers, lipids, and antioxidants. Changes were observed in the color and viscosity of the soups. The standard dehydrated soup was characterized as shiny, creamy, with seasoning flavor and fragments, and a pale-yellow color; the formulation with spinach, as grainy, with an herb odor and flavor, seasoning fragments, and a dark-green color; and with S. platensis, with herb flavor, seasoning fragments, and a dark-green color. The developed formulations are within the microbiological standards for food established by the Brazilian legislation. The sensory analysis revealed a new market niche, and the soups containing PPB and S. platensis showed good acceptability. Peach palm flour, Spirulina platensis, and spinach are alternatives for the nutritional enrichment of dehydrated soups with high protein, ash, fiber, and antioxidant contents.