Blast Furnace Slag Mortar Research Articles

Experimental and numerical investigation of static and fatigue behavior of mortar with blast furnace slag sand as fine aggregates in air and water

The experimental and analytical study are attempted to clarify the static and fatigue behavior of mortar with blast furnace slag (BFS) sand as fine aggregates in compression in air and water. The cylindrical BFS mortar specimens were used for static and fatigue compression tests in air and water and results are compared with those of mortar using crushed sand (CS). The fatigue load was applied in the form of sine signal with a constant amplitude and the frequency of 5Hz. The stress level is varied from 60%, 70% and 80% of the uniaxial compressive strength. The experimental results disclose that BFS mortar exhibits more fatigue life compared to CS mortar in air, while it is similar in water. Thereafter, the stress-strain relationships for each mortar under monotonic loading are formulated. Moreover, a simplified fatigue model for the assessment of plastic strain, total strain and fracture parameter at different number of loading cycles and for prediction of fatigue life is also proposed.

The synergistic effect of nano-silica with blast furnace slag in cement based materials

The synergistic effect of nano-silica (NS) and blast furnace slag (BFS) have been studied. A constant water-to-binder ratio (w/b) of 0.5 was used for all mortars. The different dosage (10%, 20%, 30% and 40%wt) of BFS and 3%wt NS were added into cement. The results indicated that comparing with the reference BFS mortars without silica inclusion, incorporation of a small amount of NS in cement containing BFS increased 28days compressive strength, significantly. The incorporation of 3%wt NS in the cement pastes with 30%wt dosage of BFS have the highest compressive strength (59.42MPa). In the work, the heat of hydration, non-evaporable water content and pozzolanic activity of BFS were studied, and the results showed that NS has a negative effect on the hydration of BFS; Through the analysis of the total porosity and the pore size distribution, NS and BFS can significantly reduce the porosity of the cement matrix, and increase the density, which is also an explanation of the phenomenon of increased compressive strength.

Modeling setting time and compressive strength in sodium carbonate activated blast furnace slag mortars using statistical mixture design

The alkali activation of industrial by-products have the potential to reduce the carbon dioxide emissions form the cement industry and to develop alternative mortars and concretes with properties similar or better than the ones based on ordinarily Portland cement. The used of sodium carbonate as an activator for blast furnace slag offers potential advantages over other Alkali-Activated Materials (AAMs) in terms of environmental impact and cost. This study explores the use of statistical mixture design to determine what affects initial setting time and compressive strength in sodium carbonate activated blast furnace slag mortars. This experimental design approach allows for a more thorough analysis of the effects of the mortar components on response variables over the entire design space. In this study the amount of each component was restricted to certain values in order for the mixture to react and produce a mortar with acceptable mechanical strength and setting time. The mortars obtained were tested according to ASTM C403 and ASTM C109 standards for initial setting time and compressive strength. The statistical design and analysis was done using Design-Expert 9.0. This study finds that initial setting time and compressive strength of these materials are highly dependent on the composition of the materials and proposes a model for setting time and compressive strength prediction. It was found that the two-factor interactions with sodium carbonate are statistically significant in the compressive strength model but not in the initial setting time model. A typical sample was characterized by Scanning Electron Microscopy.

Increasing the sustainability of alkali-activated binders: The use of sugar cane straw ash (SCSA)

Alkali-activated binders are the new trend in building construction studies due their good mechanical properties and environmental advantages. These type of binders are obtained by a mixing of a solid precursor with an activating solution. In this study, the influence of sugar cane straw ash (SCSA) obtained from an auto-combustion process on blast-furnace slag (BFS) based alkali-activated binders was assessed as solid precursor. The studied proportions of BFS/SCSA were 100/0 (control), 85/15, 75/25, 67/33 and 50/50 (by mass). Regarding to the activating solutions, three different mixtures were used: only NaOH (8molkg−1 Na+) and two different combinations of NaOH with sodium silicate (8molkg−1 Na+ and SiO2/Na2O molar ratios of 0.50 and 0.75). The water/binder was maintained constant. To assess the influence of SCSA on BFS-alkali activated binders, mortars were evaluated in terms of compressive strength (3–90days curing time at room temperature and 3days at 65°C); and pastes were studied to justify these results by means of thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The presence of SCSA in the binder greatly improved the compressive strength when compared to the control BFS mortars, reaching values higher than 50MPa after 90days. SCSA/BFS samples activated with sodium hydroxide yielded similar compressive strength values to those obtained for BFS mortars activated with sodium silicate. In the new binders, the partial replacement of BFS, the total replacement of sodium silicate solution and a new way of valorizing sugar cane straw enhanced sustainability.

Use of Artificial Neural Network for the Simulation of Radon Emission Concentration of Granulated Blast Furnace Slag Mortar.

In this study, an artificial neural networks study was carried out to predict the quantity of radon of Granulated Blast Furnace Slag (GBFS) cement mortar. A data set of a laboratory work, in which a total of 3 mortars were produced, was utilized in the Artificial Neural Networks (ANNs) study. The mortar mixture parameters were three different GBFS ratios (0%, 20%, 40%). Measurement radon of moist cured specimens was measured at 3, 10, 30, 100, 365 days by sensing technology for continuous monitoring of indoor air quality (IAQ). ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of two input parameters that cover the cement, GBFS and age of samples and, an output parameter which is concentrations of radon emission of mortar. The results showed that ANN can be an alternative approach for the predicting the radon concentration of GBFS mortar using mortar ingredients as input parameters.

Antifungal performance of BFS mortar with various natural antifungal substances and their physical properties

This study discusses the basic physical properties, as well as the durability and antifungal performance of blast furnace slag (BFS) mortar with various natural antifungal substances. As a series of basic experiments, the antifungal performances of various natural antifungal substances extracted from Marjoram, Phytoncide, Thyme, Ginkgo leaves, and Chitosan were investigated on five types of mold: Chaetomium globosum, Aspergillus niger, Aureobasidium pullulans, Gliocladium virens, and Penicillium pinophilum. Marjoram and phytoncide extracts, which showed excellent antifungal performance in the basic experiment, were selected and applied to the antifungal mortars. The physical properties in addition to the durability and antifungal performance of the antifungal mortars were investigated. The results clearly showed that the antifungal mortars with the marjoram extract had excellent antifungal performance compared with other antifungal mortars with natural antifungal substances. Their antifungal performance was at an equivalent level to that of the mortars with organic chemical antifungal agents. It was also shown that the optimum addition rate of marjoram extract in the mortar was 3% by mass of binder, considering antifungal performance and durability. The adverse effect of marjoram and phytoncide extract on the consistency and strength of antifungal mortars was insignificant.

Effects of Calcium Aluminate Compounds on Hydration of BFS

Blast furnace slag(BFS) is well known for its hardening mechanism in ordinary Portland cement with alkali activation due to its latent hydraulic property. The possibility of using calcium compound as activator for BFS has been investigated in this study. The hydration properties of calcium compound activated BFS binders were explored using heat of hydration, powder X-ray diffraction and compressive strength testing. Heat of hydration results indicate that the hydration heat of BFS is lower than OPC paste by about 50%. And ettringite as hydration product was formed continuously as the calcium sulfate was decreased. The maximum compressive strength of hardened BFS mortar at 28 days is confirmed to be 83% as compared with hardened OPC mortar.

Effects of Activator Properties and Ferrochrome Slag Aggregates on the Properties of alkali-activated Blast Furnace Slag Mortars

An innovative way of utilizing ground granulated blast furnace slag is to activate it using alkaline materials. The main objective of this study was to investigate the effects of activator type and curing conditions on the compressive strength and electrical resistivity of alkali-activated ground granulated blast furnace slag mortars. To obtain mortars consisting of waste materials was also an objective of the study. Ferrochrome slag was used as aggregate in some mixtures to investigate the effect of this waste material when used as an aggregate. As a result, both the binder and the aggregates were waste materials in some of the mixtures prepared. Test results indicated that for the standard water curing at $$20\,^{\circ}{\rm C}$$ , the compressive strength of the alkali-activated mortars was lower compared to that of the Portland cement, although these strengths may be considered enough for low and moderate strength applications. Higher strengths were obtained with the use of hot water curing. The test results demonstrated that the alkali-activated blast furnace slag containing waste ferrochrome slag as aggregate may achieve strength properties comparable or even higher than the ones produced with ordinary Portland cement and natural aggregates. Electrical resistivities of these alkali-activated mixtures were also significantly higher compared to that of the reference mixture.

소성조건 및 분말도에 따른 소성하수슬러지(CSS)의 포졸란 특성

This study discussed the pozzolanic properties of calcined sewage sludge (CSS) according to calcination and fineness conditions. The chemical and mineralogical analysis of CSS according to calcination temperature and time were carried out and compared with that of the existing pozzolanic materials such as fly-ash, blast furnance slag and meta-kaolin. Various mortars were made by mixing those CSS and Ca(OH)2 (1:1 wt. %), and their compressive strength and hydrates according to experimental factors such as fineness of CSS and curing age were also investigated in detail. The results show clearly the potentiality of calcined sewage sludge (CSS) as an admixture materials in concrete, but the CSS should be controlled by calcination temperature and time, and fineness etc. In this experimental condition, the calcination temperature of 800°C, calcination time of 2 hours and fineness of 5,000 cm 2 /g were optimum conditions in consideration of the mechanical properties and economic efficiency of CSS. The compressive strength of CSS mortars was higher than that of fly-ash mortars and blast furnace slag mortars, especially at the early ages. Then, the utilization of CSS in construction fields was greatly expected.

미생물 혼합 고로슬래그 모르타르의 강도특성 평가

미생물 혼합 고로슬래그 모르타르의 강도특성 평가

알칼리 자극제의 종류 및 치환율이 고로슬래그 미분말 모르타르의 압축강도에 미치는 영향

In this study, effect of types and replacement ratio of alkali activator on compressive strength of ground granulated blast furnace slag mortar has been reviewed. Types of alkali activator are NaOH, Ca(OH)2, Na2SO4, and KOH. Replacement ratio of alkali activator is 7.5, 10, 12.5, and 15%, respectively. As results, under high temperature curing condition, 1 day compressive strength development with NaOH and KOH was higher than that of Ca(OH)2 and Na2SO4. Regardless of types of alkali activator, compressive strength increased with increasing pH. This can be explained by the fact that impermeable film on the surface of slag which is generated when slag contacts water has been destroyed by alkali activator, and this promotes hydration reaction. Also, 1 day age compressive strength of specimen with high temperature curing was higher than that of specimen with standard curing. 28 days age compressive strength of specimen with high temperature curing was less than or equal to that of specimen with standard curing.

Use of Artificial Neural Network for the Prediction of Ammonia Emission Concentration of Granulated Blast Furnace Slag Mortar

Use of Artificial Neural Network for the Prediction of Ammonia Emission Concentration of Granulated Blast Furnace Slag Mortar

반응표면분석법에 의한 탄소포집 활성 고로슬래그 모르타르의 최적배합 도출에 관한 연구

PURPOSES : In this study blast furnace slag, an industrial byproduct, was used with an activating chemicals, and for carbon capture and sequestration as well as strength development. METHODS : This paper presents the optimized mixing design of Carbon-Capturing and Sequestering Activated Blast-Furnace Slag Mortar. Design of experiments in order to the optimized mixing design was applied and commercial program (MINITAB) was used. Statistical analysis was used to Box-Behnken (B-B) method in response surface analysis. RESULTS : The influencing factors of experimental are water ratio, Chemical admixture ratio and Curing temperature. In the results of response surface analysis, to obtain goal performance, the optimized mixing design for Carbon-Capturing and Sequestering Activated Blast-Furnace Slag Mortar were water ratio 40%, Chemical admixture ratio 58.78% and Curing temperature of . CONCLUSIONS : Compared with previous studies of this experiment is to some extent the optimal combination is expected to be reliable.

Improvement of the performance of alkali activated blast furnace slag mortars with very finely ground pumice

This work investigates the strength and durability of alkali activated blast furnace slag mortars (AAS) with very finely ground pumice (P) at certain rates. BFS was used instead of cement at the rate of 60% and 80%. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) alkalis were added as solution into the mixture. First stage Na2O 6, 7 and 8wt% of the BFS was added. Better results were obtained from the strength values of the sample containing 8% Na2O. Because of this result, in the second stage, pumice was used instead of 5% and 10% of the BFS. However, silicate modules (MS=SiO2/Na2O) in both experimental studies were calculated as 0.5, 0.75 and 1.00. The durability values of the AAS+P samples were better than those of the reference samples.

탄소포집 활성 고로슬래그 모르타르의 기초특성에 관한 연구

PURPOSES : To investigate the fundamental characteristics of blast-furnace slag mortar that was hardened with activating chemicals to capture and sequester carbon dioxide. METHODS : Various mix proportions were considered to find an appropriate stregnth development in regards with various dosages of activating chemicals, calcium hydroxides and sodium silicates, and curing conditions, air-dried, wet and underwater conditions. Flow characteristics was investigated and setting time of the mortar was measured. At different ages of 3, 7 and 28days, strength development was investigated for all the mix variables. At each age, samples were analyzed with XRD. RESULTS : The measured flow values showed the mortar lost its flowability as the activating chemicals amount increased in the scale of mole concentration. The setting time of the mortar was relatively shorter than OPC mortar but the initial curing condition was important, such as temperature. The amount of activating chemicals was found not to be critical in the sense of setting time. The strength increased with the increased amount of chemicals. The XRD analysis results showed that portlandite peaks reduced and clacite increased as the age increased. This may mean the <TEX>$Ca(OH)_2$</TEX> keeps absorbing <TEX>$CO_2$</TEX> in the air during curing period. CONCLUSIONS : The carbon capturing and sequestering activated blast-furnace slag mortar showed successful strength gain to be used for road system materials and its carbon absorbing property was verified though XRD analysis.

석고를 혼합한 알칼리 활성화 슬래그 모르타르의 특성

This study investigated the effects of blast furnace slag mortars activated with sodium hydroxide(NaOH) and gypsum in relation to flow, setting time and compressive strength. The parameters in this studied was the gypsum ratio 0 to 50%, 3M and 6M of activator concentration and and of curing temperatures. The results of flow was increase, setting time was increase as the amount of gypsum increases. But the results of compressive strength was dependent on the gypsum ratio, indicating that the compressive strength increased with the increase of the amount of gypsum until a certain limit, beyond which the strength decreased quickly.

알칼리 활성 고로슬래그 미분말 모르터의 알칼리-실리카 반응에 관한 실험적 연구

연구의 목적은 반응성 골재를 함유한 알칼리 활성화 고로슬래그 미분말의 알칼리-골재반응으로 인한 팽창을 조사하기 위한 것이다. 또한 이 연구는 현재 존재하고 있는 반응성 골재와 알칼리 재료들의 거동과 관련하여 특별히 관여 되어 지고 있다. 실험 방법은 EDS, SEM을 통하여 알칼리-실리카 반응 생성물의 구성이나 미세구조를 관찰하였으며 알칼리-실리카 반응에 의한 모르터 바의 팽창정도를 측정하였다. 실험 결과에 따르면 알칼리-활성화된 모르터는 알칼리 실리카 반응 때문에 팽창이 되었지만 14일 재령에서 0.1%의 팽창률을 나타내어 알칼리-실리카반응에 대하여 안전한 것으로 나타났다. 그리고 촉진 실험 후 SEM과 BEM분석한 결과 골재 주변과 시멘트 페이스트에 알칼리-실리카 겔 및 띠 모양의 생성물이 나타난 것을 볼 수 있었다. EDX에 따르면 반응생성물이 알칼리 활성화 고로슬래그를 사용하였을 경우 현격히 감소한 것을 볼 수 있다. 추가적으로 광물학적 혼화재료의 대체 재료로써 콘크리트 내구성의 특성을 보증하기 위하여 알칼리 활성화 고로슬래그의 품질을 향상시키는 연구가 필요하다. The purpose of this study was to investigate the expansion of alkali-activated mortar based on ground granulated blast furnace slag containing reactive aggregate due to alkali-silica reaction. In addition, this study was particularly concerned with the behavior of these alkaline materials in the presence of reactive aggregates. The experimental program included expansion measurement of the mortar bar specimens, as well as the determination of the morphology and composition of the alkali-silica reaction products by using scanning electron microscopy(SEM), and energy dispersive x-ray(EDX). The experiment showed that while alkali-activated ground granulated blast furnace slag mortars showed expansion due to the alkali-silica reaction, the expansion was 0.1% at Curing Day 14, showing that it is safe. After the accelerated test, SEM and BEM analysis showed the presence of alkali-silica gel and rim around the aggregate and cement paste. According to the EDX, the reaction products decreased markedly as alkali-activated ground granulated blast furnace slag was used. In addition, for the substitutive materials of mineral admixture, a further study on improving the quality of alkali-activated ground granulated blast furnace slag is needed to assure of the durability properties of concrete.

Effects of thermal and mechanical activation methods on compressive strength of ordinary Portland cement–slag mortar

Activation methods and curing regimes have crucial effects on the strength of mortars and concretes. The objective of this investigation is to examine the early and later compressive strength of activated ordinary Portland cement (OPC)–ground granulated blast-furnace slag (GGBFS) mortars and identify the most effective activation technique. The methods of activation used were thermal, mechanical and thermal–mechanical combined. Two curing regimes were adopted and five groups of mortars were prepared. It was observed that OPC–GGBFS mortars have greater sensitivity to OPC mortars against the curing regimes. However, the study revealed that there was no particular activation method which when used gave the best results for both early and later strengths and did not cause strength loss. It also proved that the most effective activation method for early strength is a combination of both the thermal and mechanical, while for later strengths, none of the activation methods was recommended.

Durability of blast-furnace slag mortars subjected to sodium monofluorophosphate application

The aim of this study is to investigate the effect of sodium monofluorophosphate (Na-MFP) on frost scaling durability and transport properties of carbonated blast-furnace slag cement (BFSC) mortar. The application of Na-MFP solution as curing solution and also surface treatment compound for BFSC mortar was evaluated. Three different Na-MFP solutions with concentrations of 10%, 20% and 30% by weight. in water were used as curing solution and surface treatment compound. The experimental results reveal that both techniques significantly improve the frost salt scaling durability and microstructure of carbonated blast-furnace slag mortar. Moreover, the carbonation rate and capillary water uptake of the treated mortars were substantially decreased compared with the untreated specimen. The mortars cured in Na-MFP solution show higher compressive strength than the untreated control after carbonation exposure. In general, the durability performances were improved when increasing the concentration of the Na-MFP solution applied.

The effect of MgSO 4 and HCL solutions on the strength and durability of pozzolan cement mortars

Pozzolan cements are produced by adding pozzolans such as silica fume, rice husk ash, blast furnace slag, fly ash, trass in 20% replacement for Portland cement. On the 28th day of production, the produced specimens are stored in water, in MgSO 4·7H 2O (5%) solution and in HCl (pH = 2) solution. The strengths and weights were determined after the mortars are stored in solutions for 56 days. Compressive strengths of the mortars stored in water for 28 days are silica fume, rice husk ash, and control, 43.3, 40.1, and 31.0 MPa, respectively. The highest loss of compressive strength is 20% and the highest gain of weight is 4.2%, occurring in blast furnace slag mortar in MgSO 4.