Water Absorption Of Specimens Research Articles

Experimental evaluation of salt corrosion resistance of potassium salt magnesium phosphate cement coating slurry

In this work, a self-compacting potassium salt magnesium phosphate cement (PMPC) coating slurry was prepared by improving the water binder ratio and adding an appropriate amount of water glass (WG) and silica microfume (SMP). By performing long-term solution immersion tests, the following conclusions can be drawn: the remaining flexural and compressive strength values (Δff and Δfc) of the PMPC specimens (M2) containing 2 % WG and 10 % SMP immersed in water, 3.5 % NaCl solution, and 5 % Na2SO4 solution for 540 days were greater than 95 % and 90 %, respectively. In comparison to the reference PMPC specimen without WG and SMP (M0), the Δff and Δfc increased by more than 30 % and 25 %, respectively. After 540 days in 3.5 % NaCl solution and 5 % Na2SO4 solution, the salt corrosion coefficients (Kf and Kc) of the M2 specimen were all greater than 1. After excluding the factor of water corrosion, the salt crystals in the solution had a strengthening effect on the hardened PMPC paste. The M2 specimens experienced volume expansion after being immersed in a solution composed of water, 3.5 % NaCl solution, and 5 % Na2SO4 solution for 540 days (7.21× 10−4, 13.52 × 10−4, and 10.92 × 10−4); this expansion was significantly lower than that of the M0 specimen under the same conditions (13×10−4, 18.5×10−4, and 21.5×10−4) due to the relatively denser initial structure. The initial water absorption rate of M2 (0.64 %–0.66 %) was significantly lower than that of M0 (0.72 %–0.75 %). After soaking in water, 3.5 % NaCl solution, and 5 % Na2SO4 solution for 540 days, the water absorption of the M2 specimens increased by 64.6 %, 7.6 %, and 12.5 %, respectively, which is clearly lower than that of M0 specimens (95.9 %, 22.7 %, and 30.6 %). The increase in the water absorption of the specimen in the salt solution was also obviously smaller than that in the aqueous solution.

Mechanical and microstructural characteristics of geopolymer mortars at high temperatures produced with ceramic sanitaryware waste

Excessive amounts of solid wastes are generated by the ceramic sanitaryware sector in the world. Recycling ceramic wastes is one of the crucial solutions to ensure their elimination. This experimental study investigates the mechanical and microstructural characteristics of geopolymer mortars with recycled ceramic sanitaryware waste powder (CSW) exposed to high temperatures. The geopolymer mixtures are produced using CSW with four different molarity (10, 12, 14, and 16 M) of NaOH as alkali-activator and two water/binder ratios (0.45 and 0.50). The investigated properties of the CSW-based Mortars (CSW-M) are the flowability, unit weight, apparent porosity, flexural strength, compressive strength, phase, and microstructure utilizing X-ray diffractometry (XRD), and scanning electron microscopy (SEM/EDS). The increase in NaOH concentration is observed to improve the flow workability of CSW-M and reduce the apparent porosity and water absorption of specimens. Mechanical test results indicate that strength values of CSW-M increase with increasing NaOH molarity. The highest strength is obtained on the CSW-M made with 16 M NaOH and 0.45 w/b ratio. The crystalline phases are determined to be mullite, quartz and albite derived from ceramic sanitaryware waste. Additionally, zeolite is formed by the secondary reaction product after elevated temperatures. Performance analysis results reveal that using ceramic sanitaryware waste is a strong alternative material as a binder to produce geopolymer mortars and contributes to the elimination of the waste.

The effect of hydrophobic amorphous carbon powder on the compressive strength, water absorption and rheological attributes of cement mortar

This paper presents the results of an experimental investigation on three different aspects of cement mortars incorporating amorphous carbon powder; rheology, strength and water absorption. Amorphous carbon powder is a by-product of the paraffin industry and was replaced with 0, 4, 6 and 8% of aggregate. Rheological tests were conducted immediately after mixing procedure, the strength of mortars was investigated by two methods; compressive and flexural at the age of 7 and 28 days. Furthermore, the water absorption of specimens was determined. Using Amorphous carbon powder was detrimental in terms of workability. However, after 28 days compressive and flexural strengths increased and water absorption declined with the addition of amorphous carbon powder, thus reducing the risk to degradation over time in severe environments.

Application of bacterial nanocellulose fibers as reinforcement in cement composites

In this study, the potential effect of bacterial nano-cellulose on mechanical properties of cement mortar was evaluated. For this purpose, bacterial nano-cellulose (BNC) directly as powder and gel (0.1, 0.3, and 0.5 wt%), and indirectly as coated onto the polypropylene fibers were used in the preparation of cement paste in order to investigate the effect of each method on the flexural strength, compressive strength and water absorption of specimens. Results indicated that samples containing BNC gel and powder enhanced mechanical properties. However, BNC-gel indicated inferior properties compared to powder. The maximum increase in flexural strength between all samples was observed in the specimens containing 0.5% of BNC powder, which was 104%, compared to the control sample. In addition, utilizing nanofibers decreased the water absorption of cement mortar. The water absorption of specimens containing 0.1% of the gel fibers and 0.3% of powder was decreased by 26% and 37%, respectively. According to scanning electron microscopy (SEM) analysis, the roughness and specific surface of polypropylene fibers coated with BNC were increased. This can improve the interaction of these fibers with the cement matrix. The results show clearly that the application of BNC nanofibers improves the mechanical properties of cement paste and workability of polypropylene fibers.

Mechanical and Rheological Properties of Self-Compacting Concrete Containing Al2O3 Nanoparticles and Silica Fume

In this paper, an experimental study of the mechanical and rheological properties of self-compacting concrete (SCC) containing Al2O3 nanoparticles (AL2O3 NPs) and silica fume (SF) has been investigated. In order to evaluate the fresh properties of concrete, Slump flow, V-funnel, and L-box tests have been conducted. The hardened concrete properties have been investigated using compressive and tensile strength tests. Also, water absorption of specimens has been evaluated using the water absorption test. Thirteen different amounts of AL2O3 NPs (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, and 3%) as a substitute of cement were used. The amount of SF in all specimens is considered constant. According to the tests, the compressive strength of specimens containing 2.5% AL2O3 NPs as partial cement replacement after 7, 28, and 90 days is increased by 47, 88, and 86%, respectively. The reason for this enhancement is the reactivity of the AL2O3 NPs with Portland cement during the hydration process of cement. Also, the splitting tensile strength of specimens containing 2.5% AL2O3 NPs and 10% SF as partial cement replacement after 7, 28, and 90 days is increased by 29, 55, and 47%, respectively. On the other hand, the use of 1 and 2% of aluminum nanoparticles also reduced water absorption by 10% and 45%, respectively. In other words, the use of SCC in SCC containing silica fume has a positive effect and can be effective in cases where low water absorption is required.

Influences of Zeta Potential, Water Absorption and Surface Roughness of Porous Ceramics on Marine Bio-fouling

The red tide organisms occurring at seashores in Korea damage the marine fish-raising industry every summer. Several methods to prevent the occurrence of red tide organisms, therefore, have been tried; one of them is to filter out red tide organisms using a membrane filled with porous ceramic bodies, allowing only fresh seawater to pass into a fish farm. When this method is used for long period of time, however, the problem of marine bio-fouling can develop on the surfaces of the porous ceramic body, deteriorating the filtering function of the porous bodies. In this paper, the influences of the zeta potential, water absorption and surface roughness of porous ceramics on marine bio-fouling have been inspected. In order to control the above three factors, three kinds of ceramic powders, alumina, titania and zirconia, were coated on the porous bodies. As a result, the water absorption and the surface roughness of the porous ceramics were found to be equally important factors in preventing bio-fouling, while the zeta potential of the specimens did not show a prominent effect. In detail, the water absorption of specimens was an effective factor in the early stages of bio-fouling for about one month; on the other hand, the surface roughness of the specimen was a main factor that could be used to control the amount of bio-fouling after one month. Among the three ceramic powders used as coatings, alumina, by imparting lower water absorption and higher surface roughness to the specimens, proved to be the optimum one to prevent marine bio-fouling.

The effects of nano-silica and nano-alumina on frost resistance of normal concrete

In this study frost resistance and mechanical properties of concrete containing nano-silica and nano-alumina are studied. Nano-particles were employed as a partial substitute of cement. The specimens were subjected to cycles of freezing and thawing in water according to ASTM C666A. The reduction in compressive strength, loss of mass, change in length and water absorption of specimens was measured after specified number of freeze and thaw cycles. Experimental results showed that the frost resistance of concrete containing nano-particles were considerably improved, as result of a more compacted microstructure. It was also concluded that the frost resistance of concrete containing nano-Al2O3 was better than that containing the same amount of nano-SiO2. Compressive strength of normal concrete containing nano-SiO2 was higher than that containing the same amount of nano-Al2O3.

RETRACTED ARTICLE: Prediction water absorption resistance of lightweight geopolymers by artificial neural networks

In the present work, water absorption of lightweight geopolymers produced by fine fly ash, rice husk bark ash and palm oil clinker (POC) aggregates has been modeled based on artificial neural networks. To build the models, training, validating and testing using experimental results from 144 specimens were conducted. The data used in the multilayer feed-forward neural networks models are arranged in a format of six input parameters that cover the quantity of fine POC particles, the quantity of coarse POC particles, the quantity of FA+RHBA mixture, the ratio of alkali activator to ashes mixture, the age of curing and the test trial number. According to these input parameters, in the neural networks models, the water absorption of each specimen was predicted. The best value of R2 was 0.9972 and the minimum value of that was 0.8301. The training, validating and testing results in the neural networks model have shown a strong potential for predicting the water absorption of the geopolymer specimens.

RETRACTED ARTICLE: Utilizing ANFIS for prediction water absorption of lightweight geopolymers produced from waste materials

In the present work, water absorption of lightweight geopolymers produced by fine fly ash and rice husk–bark ash together with palm oil clinker (POC) aggregates has been investigated experimentally and modeled by adaptive network-based fuzzy inference systems (ANFIS). Different specimens made from a mixture of fine fly ash and rice husk–bark ash with and without POC were subjected to water absorption tests at 2, 7, and 28 days of curing. The specimens were oven cured for 36 h at 80 °C and then cured at room temperature until 2, 7, and 28 days. The results showed that high amount of POC particles improve the percentage of water absorption at the early age of curing. In addition, the ratio of “the percentage of water absorption” to “weight” of the POC-contained specimens at all ages of curing was much higher than that of POC-free specimens, which make them suitable for lightweight applications. To build the model, training, validating, and testing using experimental results from 144 specimens were conducted. The used data in the ANFIS models are arranged in a format of six input parameters that cover the quantity of fine POC particles, the quantity of coarse POC particles, the quantity of FA + RHBA mixture, the ratio of alkali activator to ashes mixture, the age of curing, and the test trial number. According to these input parameters, the water absorption of each specimen was predicted. The training, validating, and testing results in the ANFIS models showed a strong potential for predicting the water absorption of the geopolymer specimens.

RETRACTED: Fuzzy logic for prediction water absorption of lightweight geopolymers produced from waste materials

Abstract In the present work, water absorption of lightweight geopolymers produced by fine fly ash and rice husk bark ash together with palm oil clinker (POC) aggregates has been investigated experimentally and modeled by fuzzy logic. Different specimens made from a mixture of fine fly ash and rice husk bark ash with and without POC were subjected to water absorption tests at 2, 7 and 28 days of curing. The specimens were oven cured for 36 h at 80 °C and then cured at room temperature until 2, 7 and 28 days. The results showed that high amount of POC particles improve the percentage of water absorption at the early age of curing. In addition the ratio of “the percentage of water absorption” to “weight” of the POC-contained specimens at all ages of curing was much higher than that of POC-free specimens which make them suitable for lightweight applications. To build the model, training, validating and testing using experimental results from 144 specimens were conducted. The used data in the fuzzy model are arranged in a format of six input parameters that cover the quantity of fine POC particles, the quantity of coarse POC particles, the quantity of FA + RHBA mixture, the ratio of alkali activator to ashes mixture, the age of curing and the test trial number. According to these input parameters, the water absorption of each specimen was predicted. The training, validating and testing results in the fuzzy model have shown a strong potential for predicting the water absorption of the geopolymer specimens.

Investigation on the Aging Properties of Silicone Coating in Marine Concrete

This paper reports result of a study conducted to evaluate the aging properties of isobutyl triethoxysilane coating used in marine concrete. The silicone coating was brushed to the surface of mortar specimens and the aging properties of the silicone coating were investigated by thermal aging and ultraviolet (UV) aging. The water absorption of the mortar specimens applied with the silicone coating increases with the extension of the aging time. And the higher aging temperature, the bigger the water absorption. Because of the combined effect of light and heat, water absorption of specimens after UV aging at 60 °C is larger than that after thermal aging in the same temperature. In addition, noticeable variation in aging properties of the same silicone coating by different manufacturers is noted.

RETRACTED: Prediction of Resistance to Water Damage of Geopolymers with Seeded Fly Ash and Rice Husk Bark Ash by Fuzzy Logic

In this study, percentage of water absorption of geopolymers made from seeded fly ash and rice husk bark ash has been predicted by fuzzy logic. Different specimens, made from a mixture of fly ash and rice husk bark ash in fine and coarse forms, together with alkali activator made (a solution of water glass and NaOH), were subjected to permeability tests at 7 and 28 days of curing. The curing regime was different: one set of the specimens was cured at room tem- perature until 7 and 28 days and the other sets were oven cured for 36 h at the range 4090 � C and then cured at room temperature until 7 and 28 days. A model based on fuzzy logic for predicting the percentage of water absorption of the specimens has been presented. To build the model, training and testing using experimental results from 120 specimens were conducted. The data used as inputs of fuzzy logic model are arranged in a format of six parameters that cover the percentage of fine fly ash in the ashes mixture, the percentage of coarse fly ash in the ashes mixture, the percentage of fine rice husk bark ash in the ashes mixture, the percentage of coarse rice husk bark ash in the ashes mixture, the temperature of curing, and the time of water curing. According to these input parameters, in the fuzzy logic model, the percentage of water absorption of each specimen was predicted. It has been found that fuzzy model will be valid within the ranges of variables. The training and testing results in the fuzzy logic model have shown a strong potential for predicting the percentage of water absorption of the geopolymer specimens.

Water absorption of boron-treated and heat-modified wood

Heat treatments change the chemical and physical properties of wood and dimensional stability and hygroscopicity are affected as a result of modifications of wood cell components. This study evaluated the water absorption of wood specimens treated with boron compounds followed by heat treatment. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or disodium octoborate tetrahydrate (DOT) solutions were heat-modified at either 180° or 220°C for 2 or 4 h. Carbohydrate composition and water absorption of the specimens were then measured and compared with those of untreated and unheated specimens. Wood carbohydrates were significantly degraded in the specimens after heat treatment. The heat treatment evidently decreased the water absorption and the heat-modified specimens absorbed less water than unheated specimens. The higher the treatment temperature and the longer the treatment time, the lower the amount of absorbed water. The boron-treated and heat-modified specimens, however, showed increased water absorption due to the hygroscopic properties of BA and DOT.