Rapid Chloride Ion Permeability Research Articles

Effect of Supplementary Cementitious Materials with Similar Specific Surface Area on Cementitious Composite Systems

Abstract This study investigated the effect of the mechanical and durability properties of cementitious composite systems with supplementary cementitious materials (SCMs), including fly ash (FA), ground granulated blast furnace slag (GGBS), and bottom ash (BA), with similar specific surface areas (∼3,300 cm2/g). FA, GGBS, and BA were ground to a specific surface area of ∼3,300 cm2/g (about the cement-specific surface area) and then replaced with cement at 5 %, 10 %, 15 %, and 20 % replacement ratios. The compressive strength, flexural strength, length change, and rapid chloride ion permeability of the cementitious composites incorporating FA, GGBS, and BA with similar specific surface areas were recorded after 7-, 28-, and 90-day curing periods. As a result, cementitious composites containing GGBS improved the mechanical and durability properties at the maximum rate. It was shown that the properties of cementitious composites containing 20 % GGBS yielded better results than the control specimens without any SCMs.

Investigating the load-deflection behaviour and drying shrinkage resistance of HPC reinforced using different cellulose fibres

High-performance concrete (HPC) families exhibit superior compressive strength and excellent durability. However, HPC owing to its higher binder content and dense microstructure shows brittle failure under tensile loading and is susceptible to volumetric changes under drying shrinkage. The issues related to inferior ductility and lower shrinkage resistance of HPC were resolved by using different types of agro-fibres. This paper examined the influence of different agro-based fibres i.e., coconut fibre (CF), jute fibre (JF), and banana fibre (BF) on the flexural-tensile and drying shrinkage response of HPC. The behaviour of agro fibres was compared with that of synthetic polypropylene fibre (PPF). Investigated parameters include load-deflection response, compressive strength (CS), splitting-tensile strength (STS), drying shrinkage (DS) response, and rapid chloride ion permeability (RCIP) capacity. The results showed that in overall mechanical performance, JF and BF yielded better strength properties than CF and synthetic PPF. The addition of 0.3 vol% of JF and BF increased flexural strength (FS) by more than 20%. In terms of the flexural behaviour of HPC, both JF and BF owing to their superior tensile strengths showed higher efficacy than the synthetic PPF. Among agro-fibres, JF shows beneficial effects on the shrinkage resistance of HPC. BF and CF were useful in reducing the DS at 0.1% volume, however, the increase in the volume of these two fibres aggravated the shrinkage problem. As compared to PPF and other agro-fibres, JF yielded relatively better performance in terms of enhancing strength properties as well as shrinkage resistance of HPC.

Effect of binder strengthening using micro-silica on mechanical and absorption characteristics of HPC reinforced with reclaimed jute fibres

The incorporation of dispersed fibres in the binder matrix is proven to be beneficial to the tensile performance of high-performance concrete (HPC). However, the insertion of new/virgin fibres in the ‘concrete matrix’ significantly adds to the final cost and embodied carbon of HPC. Therefore, the environment-friendly design of fibre-reinforced HPC remains the main challenge. In this study, the influence of different volume fractions (Vol.) of ‘jute fibre’ (JF) was examined on the engineering performance of HPC. The effect of micro-silica/silica fume (SF) inclusion as a secondary binder was also analysed on the performance of JF-reinforced HPC. To investigate the mechanical performance of designed mixes, compression, flexure, and splitting-tensile tests were conducted at 28 and 91 days. Non-destructive durability performance indicators, such as ‘water-absorption (WA)’, ‘rapid chloride-ion permeability (RCIP)’, ‘electrical-resistivity (ER)’, and ‘ultrasonic-pulse velocity (UPV)’ were also examined. It was found that the utilisation ratio/efficiency of JF addition improved with the ageing of samples. Moreover, the inclusion of SF proved to be beneficial in the strength gain due to JF addition. The combined use of 0.3% vol. of JF and SF improved the ‘compressive strength (CS)’ by 26–30%. The inclusion of 0.3% vol. of JF improved the ‘splitting-tensile strength (STS)’ of plain HPC by 43% and 23% with and without the SF inclusion, respectively. The JF incorporation showed a minor decrease in the imperviousness of HPC. SF incorporation helped minimise the damaging effect of JF incorporation on the ER, WA resistance, and UPV value of HPC. Owing to the addition of SF, the WA capacity of JF-reinforced mixes was decreased by up to 30% at 28 days and up to 50% at 91 days. While the RCIP values of JF-reinforced mixes were dropped by 40–60% (depending on the JF content) owing to the superior pozzolanic and filler effect of SF.

Characterization of high-performance concrete using limestone powder and supplementary fillers in binary and ternary blends under different curing regimes

Although the dumping of waste generated by industries in the environment poses a hazard, it is feasible to use waste and unused materials to manufacture high-performance concrete. By recycling these wastes in binary and ternary blends, sustainable and durable concrete mixtures can be created, resulting in the development of sustainable concrete structures. Therefore, a research project was undertaken to develop high-performance concrete (HPC) using available supplementary and waste materials, such as fly ash (FA), silica fume (SF), Quartz filler (QF), and limestone powder (LSP), as partial replacements for cement in binary and ternary blends under various curing conditions. Different percentages (5, 8, 10, 15, 20%) of the supplementary materials were mixed in binary and ternary combinations to determine the optimal dosage for high-performance concrete. The fresh and hardened properties of the concrete were evaluated using various tests, including slump, compressive strength, rapid chloride ion permeability, porosity, and drying shrinkage tests. The prepared concrete specimens were tested using various concentrations of binder replacement in binary, ternary, and quaternary combinations. The results showed that incorporating quartz filler as a partial replacement of cement up to 8% yielded positive results regarding mechanical properties. However, all mixtures containing different dosages of SF, QF, FA, and LSP demonstrated significant improvement in durability-related properties under normal and high-temperature curing conditions. Interestingly, the porosity of mixtures incorporating fly ash and LSP showed a slight increase compared to identical specimens under normal curing conditions. Moreover, the drying shrinkage behavior of ultrafine fillers (QF, SF, LSP, FA) indicated that their incorporation led to an increase in the shrinkage of high-performance mixtures under normal and high-temperature curing conditions. Binary and ternary blends incorporating QF, LSP, and SF showed an increase of around 5–8% in shrinkage under high-temperature curing compared to identical specimens under normal curing conditions. Therefore, it can be concluded that QF, LSP, SF, and FA can be efficiently used to produce high-performance cementitious composites, leading to sustainable concrete material.

The Effect of Magnetized Water on the Fresh and Hardened Properties of Slag/Fly Ash-Based Cementitious Composites

The physicochemical structure of the mixing water used in concrete has a significant effect on the physical and mechanical properties of cementitious composites. The studies on the effect of magnetized water (MW) on the properties of FA/BFS-based cementitious composites are still in their infancy. This study explores the effect of MW on the fresh and hardened properties of fly ash (FA)/blast furnace slag (BFS)-based cementitious composites. A total of 22 different mixture groups having FA/BFS (0, 5, 10, 15, 20, and 25%) by weight of cement were produced using tap water (TW) and MW. The fresh-state properties (the initial and final setting times and the consistency) and hardened-state properties (the compressive strength, water absorption properties, and rapid chloride ion permeability test) of produced cementitious composites were investigated. The development of hydration products was analyzed using scanning electron microscopy (SEM) and the mercury intrusion porosimetry (MIP) test. The results reveal that the fresh- and hardened-state properties of cementitious composite samples produced with MW are significantly improved. The properties of the samples utilizing MW showed that FA and BFS could be used at a higher rate for the same target properties in cementitious composites by using MW as mixing water. Using up to 25% FA/BFS in cementitious composites prepared with MW is recommended.

Evaluation of Mechanical Properties of High Strength Banana Fibre Concrete (HSBFC) incorporating Fly ash and Silica fume

Abstract: Concrete is the most dynamic engineering material in construction industry because of its strength properties as well as its durability. The consumption of raw materials not only depleted natural resources but also increases the toxic material in the environment by the construction industries. Now a days the by using the banana fibre in concrete is an efficient sustainable method. The paper presents an Evaluation of Mechanical Properties of High Strength Banana Fibre Concrete (HSBFC) incorporating Fly ash and Silica fume in concrete. Banana fibers are widely available worldwide as agricultural waste from Banana cultivation. Banana fibers are environmentally friendly and present important attributes, such as low density, light weight, low cost, high tensile strength, as well as being water and fire resistant. Replacement of cement by Pozzolonic materials up to 40% in the proportion of 20%, 25% and 30% Fly Ash & 10% silica fume. Determination of strength parameters with different percentages of banana fibers at 0%, 1%, 1.5%, 2% by weight of cement. M70 grade concrete and ordinary Portland cement of grade 53 will be used. The banana fiber reinforced concrete will be tested for compressive strength, splitting tensile strength, flexural strength and Durability tests at different ages of 7,14 and 28 days. Detailed laboratory studies will be carried out with different proportions of banana fiber to determine property of concrete such as compressive strength test, split tensile test, Flexural strength test. Durability test such as Water Absorption, Rapid Chloride ion Permeability Test (RCPT), Carbonation Resistance test, Sulphate Attack test, Hydrochloric acid attack, Freeze–Thaw Test also worked out. The Strength of the concrete in compression and flexure by adding 1.5% of banana fibre with Cement; partially replaced by 20% of Fly Ash and partially replaced by 10% of silica fume reveals better strength as compared to other combinations as proposed in this study.

Corrosion Behavior of Rebars Embedded in Alkali-Activated and Conventional Reactive Powder Concretes

The present study investigated the corrosion behavior of reinforcement bars embedded in alkali-activated (ARPC) and conventional (CRPC) reactive powder concretes. Corrosion progress in 3.5% NaCl solution, water and air environments were monitored up to 365 days. The physical and mechanical characteristics, such as water absorption, rapid chloride ion permeability, compressive and flexural strength, and corrosion characteristics, such as half cell potential and corrosion current intensity results were compared for ARPC and CRPC matrices. Even for the same mechanical performance, alkali-activated mortars were found to have a high permeable structure and an early depassivation of the rebars occurred. In the propagation stage of chloride induced corrosion, almost 13 times higher corrosion current intensity values were measured as well as earlier deterioration and cracking was observed for ARPC compared to CRPC.

A study on the characteristics and microstructures of GGBS/FA based geopolymer paste and concrete

Abstract The purpose of this study is to focus on the durability of geopolymer concrete after nine months of an indoor and outdoor curing period. The geopolymer paste was prepared with fly ash and ground granulated blast furnace slag as raw materials and sodium silicate/sodium aluminate as an alkali activator. The geopolymer concrete was prepared with a 1:2.5:2.4 geopolymer:sand:gravel ratio. The influence of sodium aluminate, wollastonite additions and NaOH concentration on the microstructure, physical and mechanical properties were evaluated. The compressive strength of the geopolymer concrete can reach 67 MPa and 53 MPa after 180 days of indoor and outdoor curing, respectively. Rapid Chloride Ion Permeability Test (RCPT) shows the geopolymer concrete has excellent chloride resistance over prolonged curing time. After 180 days of accelerated wetting-drying cycles, the continued growth of compressive strength indicates the good weathering resistance of geopolymer concrete. According to the test results obtained during this study, the geopolymer has a high potential to be a key material for civil construction.

Optimization of durability properties of concrete containing fly ash using Taguchi’s approach and Anova analysis

DOI: 10.7764/RDLC.17.3.364 In this study, optimization of durability properties of the concretes was performed by using Taguchi method and Anova analysis. The durability performance of the concretes was evaluated using measurements of rapid chloride ion permeability, freezing-thawing resistance and sorptivity tests. The degree of freezing-thawing resistance was assessed the change of weight, ultrasonic pulse velocity (UPV) and flexural strength after 300 cycles. The use of fly ash improved the rapid chloride ion permeability and sorptivity of concrete. The best resistance to chloride ion permeability was obtained from a combination of type of class C fly ash content of 102 kg/m 3 with PC content of 332 kg/m 3 . There was a remarkable reduction in the UPV after the specimens are subjected to freezing-thawing cycles. The amounts of flexural strength loss have been measured in the range of 6.70 - 29.83%. The use of type of class C fly ash positively affected freezing-thawing resistance of concrete. The Anova analysis indicated that the cement dosage has an utmost importance on the sorptivity level, chloride ion permeability and ultrasonic pulse velocity loss. Furthermore, the fly ash percentage has an utmost importance on the weight loss and flexural strength loss.

Strength and Durability of High Volume Fly Ash in Engineered Cementitious Composites

Engineered cementitious composite (ECC) is known for its high tensile ductility, strain hardening property and high performance both in strength and durability properties due to hybridization of fibers. This study is focused on the strength and durability of high volume fly ash in engineered cementitious composites. The cement content in ECC is more than the normal or conventional concrete. This experimental investigation is aimed to reduce cement content in ECC by replacing it with high volume Class F fly ash in the range of 40%, 60%, 80% and 100%. The tests for mechanical properties such as compressive strength, flexural strength, splitting tensile strength and modulus of elasticity were performed. To determine the durability properties water absorption and rapid chloride ion permeability tests were also performed. The high volume fly ash in ECC increased the mechanical properties as the percentage of replacement of fly ash increased up to 60% beyond which the strength decreased. The water absorption of high volume fly ash exhibited lesser than 5% compared to control mixture. Similarly, the chloride ion penetration of high volume fly ash in ECC exhibited from moderate to very low chloride ion penetration as the percentage of fly ash increased from 40% to 100%. This study clearly shows that hybridization of steel and polypropylene fibers in high volume fly ash engineered cementitious composites not only improved the strength but also enhanced the durability properties when the curing period is increased

Field performance of concrete pavement incorporating recycled concrete aggregate

This paper reports test results of a field-oriented study carried out to demonstrate the performance of recycled concrete aggregate (RCA) for use in the construction of rigid pavement. Properties of eight concrete mixtures containing RCA were first compared to those of a reference mixture. Two mixtures proportioned with 30% and 40% of coarse RCA along with the reference concrete were then used for field implementation, which involved casting a 300-m long pavement section in St. Louis, Missouri. Samples were taken during slip-form pavement construction. Core samples were extracted at 120days to determine in-situ properties. Instrumentation was incorporated to monitor the long-term deformation of different pavement sections. Incorporation of 30% and 40% RCA reduced the 91-day compressive strength by 7% and 12%, and the 56-day modulus of elasticity by 22% and 14%, respectively. The 56-day splitting tensile strength and flexural strength values of the two RCA mixtures were similar to those of the reference concrete. Mixtures exhibited similar performance in terms of durability against abrasion, freeze and thaw cycles, and rapid chloride ion permeability. An increase of 100με in shrinkage was observed for the 40% RCA compared to the reference concrete. However, all field investigated mixtures exhibited similar long-term deformation patterns and magnitudes. In-situ deformation of all pavement sections was limited to 150με at sensor locations.

Effects of milled cut steel fibers on the properties of concrete

This study presents the mechanical and transport properties of milled cut steel fiber reinforced concretes (MCSFRC). Properties studied include unit weight, workability, compressive strength, flexural strength, splitting tensile strength, bond strength, water absorption, water porosity, water sorptivity, rapid chloride ion permeability and drying shrinkage of concrete. Mixtures with a waterbinder ratio of 0.40, total binder content of 500 kg/m3 and milled cut steel fiber content of 0, 0.25, 0.50 and 1.00% by concrete volume were produced and tested. The laboratory results showed a slight reduction in compressive strength with the use of milled cut steel fiber. On the other hand milled cut steel fibers significantly improved the tensile strength and decreased the drying shrinkage. Although no significant increase was observed in the absorption, porosity and sorptivity, chloride ion permeability increased drastically with the increase of milled cut steel fiber content.

Effect of alkali content of cement on properties of high performance cementitious mortar

The use of very low water-to-binder ratio (w/b) in high-performance cementitious mixtures (HPCM) such as ultra-high performance concrete (UHPC) is gaining popularity. Typically these mixtures consist of Portland cement, pozzolans, water, aggregate, chemical admixtures and steel fiber. The properties of such mixtures including workability, strength, dimensional stability and durability are sensitive to the quality and the proportions of the materials used. In particular, due to high cementitious materials content and low w/b ratio of these mixtures, the alkali content of Portland cement can have a significant effect on the fresh and hardened properties. However, there is limited information available in the literature on the influence of cement alkalinity on the properties of these mixtures. In order to have a closer examination of the influence of alkali content of cement on the properties of such mixtures, a series of Portland cement mortars having a w/c ratio of 0.20 and a range of cement alkali contents were evaluated in this study. The workability, setting time, compressive strength, drying shrinkage, rapid chloride ion penetration, volume of permeable voids and alkali–silica reaction potential of HPCM using reactive aggregate were studied as a function of the alkali content of cement ranging from 0.49% to 0.88% Na2Oeq. The test results showed that when the alkali content of cement was higher than 0.70%, the workability of HPCMs decreased significantly as the alkali content increased. An increase in the alkali content of cement delayed the time of final setting, reduced the compressive strength, and increased the rapid chloride ion permeability, drying shrinkage and volume of permeable voids of HPCM. As the alkali content of cement increased, rapid and significant expansion due to ASR was observed in HPCM, along with significant loss in flexural strength of test specimens, even though the w/c was maintained at 0.20. Identical set of tests were conducted on parallel HPCM specimens containing Class F fly ash as a cement replacement material, and significant differences in results were observed when compared with pure Portland cement mixtures.

Pore Distribution and Durability of Cement Mortar by the Magnetic Resonance Imaging

The pore distribution in cement mortar, which is highly related to compressive strength and permeability, vary with water-cement ratios and curing periods. This study used magnetic resonance imaging (MRI) to observe the pore distribution. Compressive strength tests, the rapid chloride-ion permeability test, and electrical resistivity tests were performed to determine the influence of pore distribution on durability. The results reveal that lower water-cement ratios and longer curing periods contributes to fewer pores in mortar specimens. SEM images illustrated how this may be influenced by the rate at which the hydration product, C-S-H colloids, is generated. In addition, the results of durability testing indicate that porosity and compressive strength, total charge passed, and resistivity display linear relationships, as porosity increases, the total charge passed increases, resistivity decreases, and compressive strength declines. The linear regression determined that the R2 of all relationships exceeded 0.90, thereby demonstrating the feasibility of applying MRI to assess the durability of concrete.

Performance evaluation of structural concrete using controlled quality coarse and fine recycled concrete aggregate

This paper presents the fresh, mechanical, and durability performance, of a structural concrete mix classified as C-1, by the Canadian Standards Association (CSA) made with controlled quality Recycled Concrete Aggregate (RCA). Five mixes with water-to-cementing material (w/cm) ratio of 0.40 were produced with various RCA contents and tested against two 0% RCA control mixes made with General Use (GU) cement, and General Use Limestone cement (GUL). The RCA contents in the mixes were 10%, 20%, and 30% by coarse aggregate volume replacement, as well as 10% and 20% fine and coarse (granular) aggregate volume replacement. All evaluated mixes met the specifications from the CSA for fresh, mechanical, and durability properties. The coarse RCA mixes performed better than the granular RCA mixes in terms of flexural and splitting tensile strengths, linear drying shrinkage, water sorptivity, and rapid chloride-ion permeability, where the test results were significantly affected by the ultra fines present in the granular RCA.

Permeability properties of self-consolidating concrete containing various supplementary cementitious materials

In this study, permeability properties of 17 self-consolidating concrete (SCC) mixtures containing various supplementary cementitious materials (SCM) were investigated by different experimental approaches. The effects of SCM type and content on the compressive strength, rapid chloride ion permeability (RCPT), water penetration depth, water absorption and sorptivity were studied. For these purposes, various amounts of silica fume (SF), metakaolin (MK), Class F fly ash (FAF), Class C fly ash (FAC) and granulated blast-furnace slag (BFS) were utilized in binary, ternary, and quaternary cementitious blends. Results showed that partial replacement of PC by SCM increased the compressive strength of control mixtures at 28 and 90days (except for FAF at 28days). Mixtures containing MK presented a better performance compared to other SCM at 7days. The utilization of SCM reduced the RCPT results of almost all mixtures compared to the control mixtures and the reduction was more significant with an increase in the SCM content. All of the mixtures containing SCM had lower penetration depths when compared to reference mixtures at 28 and 90days. Good correlations were established between the percentage of permeable voids and water absorption. Moreover, there was an inverse but almost linear relationship between permeable voids content and compressive strength of the mixtures.

부순모래를 사용한 습식 숏크리트의 광물성 혼화재료 혼입에 따른 내구성 평가

The purpose of this dissertation was to investigate the effect of mineral admixtures, such as fly ash, blast furnace slag powder, meta kaolin and silica fume, on the basic properties and durability of crushed sand shotcrete, selecting a series of shotcrete mixtures with a variable admixture. Compressive strength increased as the content of mineral admixtures increased, specially it was the most effective when using meta kaolin both at sample specimen and core after shotcreting. Rapid chloride ion permeability test and sulfuric acid resistance test showed that both durability increased as the substitute rate of mineral admixture increased. In air void analysis with image analysis, the targeted the spacing factor and specific surface were not satisfied because air-entrained agent was not used.

Permeation characteristics of self compacting concrete made with partially substitution of natural aggregates with rounded lightweight aggregates

This study presents transport properties of self-compacting concretes (SCCs) in which natural aggregates had been partially replaced with lightweight fine (LWFA) and coarse aggregate (LWCA). Lightweight aggregates were manufactured through the cold bonding pelletization of 90% fly ash and 10% portland cement in a tilted pan at room temperature. A total of 17 SCCs with a water/binder ratio of 0.32 were produced at a fixed slump flow of 720±20mm by adjusting the amount of High-Range-Water-Reducing-Admixture (HRWRA) used. The transport properties were investigated via water sorptivity, water permeability, rapid chloride ion permeability, and gas permeability. Mechanical properties of SCCs were determined in terms of compressive strength, splitting tensile strength, and structural efficiency. It was found that with increasing volume of LWFA and/or LWCA, the hardened properties reduced regardless of testing age. Moreover, in spite of lower compressive strength, SCCs with LWFA had better performance in the case of durability related properties compared to the SCCs with LWCA.

Strength and transport properties of steam cured and water cured lightweight aggregate concretes

In this paper, effect of steam and water curing on the compressive strength development and transport properties such as water sorptivity, rapid chloride ion permeability, and gas permeability of concretes containing various volumes of lightweight fly ash aggregate (LWA) were investigated. In production of concrete, a fixed amount of lightweight coarse (LWCA) aggregate plus varying amounts of lightweight fine aggregate (LWFA) were used. Utilization of LWFA was achieved by volumetric substitution of fine aggregate with five different replacement levels namely, 0%, 25%, 50%, 75%, and 100%. Therefore, five different concrete mixtures were produced for this experimental study. The produced concretes were divided into two parts one of which was initially steam cured while the other was directly exposed to water curing. After initial steam curing regime, the steam cured (SC) concretes were also transferred to water until testing Mechanical properties of concretes were monitored through compressive strength development over 56days, while transport properties were measured by means of water sorptivity, gas permeability and rapid chloride permeability tests conducted at 28 and 56days.

Durability aspect of concretes composed of cold bonded and sintered fly ash lightweight aggregates

This study reports the finding of an experimental study carried out on the durability related properties of the lightweight concretes (LWCs) including either cold bonded (CB) or sintered (S) fly ash aggregates. CB aggregate was produced with cold bonding pelletization of class F fly ash (FA) and Portland cement (PC) while S aggregate was produced by sintering the fresh aggregate pellets manufactured from FA and bentonite (BN). Two concrete series with water-to-binder (w/b) ratios of 0.35 and 0.55 were designed. Moreover, silica fume (SF) with 10% replacement level was also utilized for the purpose of comparing the performances of LWCs with and without ultrafine SF. The durability properties of concretes composed of CB and S aggregates were evaluated in terms of water sorptivity, rapid chloride ion permeability, gas permeability, and accelerated corrosion testing after 28days of water curing period. The compressive strength test was also applied to observe the strength level at the same age. The results revealed that S aggregate containing LWCs had relatively better performance than LWCs with CB aggregates. Moreover, the incorporation of SF provided further enhancement in permeability and corrosion resistance of the concretes.