scholarly journals Development of a New Ecological Material Based on Moroccan Industrial Wastes for Road Construction

2020 ◽  
Author(s):  
Achraf Harrou ◽  
El Khadir Gharibi ◽  
Yassine Taha ◽  
Nathalie Fagel ◽  
Meriam El Ouahabi
Keyword(s):  
Compressive Strength ◽  
Steel Slag ◽  
Road Construction ◽  
Pozzolanic Reaction ◽  
Industrial Wastes ◽  
X Ray Diffraction ◽  
Hydration Kinetics ◽  
Hydrated Calcium Silicate ◽  
Pozzolanic Reactivity ◽  
Kinetics Of

The Black Steel slag (Ss) and phosphogypsum (PG) are industrial wastes produced in Morocco. In order to reduce these two wastes and to evaluate their pozzolanic reactivity in the presence of water, they were incorporated into bentonite (B) mixed with lime (L). The studied mixtures (BLW, BL-PG-W and BL-PG-Ss-W) were analyzed by X-ray diffraction, Infrared spectroscopy, Raman spectroscopy and SEM/EDX analysis. Compressive strength tests were performed on hardened specimens. The results obtained show that the hydration kinetics of the B-L-W and B-L-PG-W mixtures are slow. The addition of PG to a bentonite-lime mixture induces the formation of new microstructures such as hydrated calcium silicate (C-S-H) and ettringite, which increases the compressive strength of the cementitious specimens. The addition of the Ss to a mixture composed by 8%PG and 8%L-B accelerates the kinetics of hydration and activates the pozzolanic reaction. The presence of C2S in the slag helps to increase the mechanical strength of the mixture B-L-PG-Ss. The compressive strength of the mixtures BL-W, BL-PG-W and BL-PG-Ss-W increases from 15 to 28 days of setting. After 28 days of setting, 8% of Sc added to the mixture 8% PG-8%L-B is responsible for an increase of the compressive strength to 0.6 MPa.

scholarly journals Phosphogypsum and Black Steel Slag as Additives for Ecological Bentonite-Based Materials: Microstructure and Characterization

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1067
Author(s):  
Achraf Harrou ◽  
El Khadir Gharibi ◽  
Yassine Taha ◽  
Nathalie Fagel ◽  
Meriam El Ouahabi
Keyword(s):  
Compressive Strength ◽  
Steel Slag ◽  
Pozzolanic Reaction ◽  
Industrial Wastes ◽  
X Ray Diffraction ◽  
Hydration Kinetics ◽  
Hydrated Calcium Silicate ◽  
Pozzolanic Reactivity ◽  
Strength Tests ◽  
Kinetics Of

The Black Steel slag (Ss) and phosphogypsum (PG) are industrial wastes produced in Morocco. In order to reduce these two wastes and to evaluate their pozzolanic reactivity in the presence of water, they were incorporated into bentonite (B) mixed with lime (L). The studied mixtures (BLW, BL–PG–W and BL–PG–Ss–W) were analyzed by X-ray diffraction, Infrared spectroscopy, Raman spectroscopy and SEM/EDX analysis. Compressive strength tests were performed on hardened specimens. The results obtained show that the hydration kinetics of the B–L–W and B–L–PG–W mixtures are slow. The addition of PG to a bentonite––lime mixture induces the formation of new microstructures such as hydrated calcium silicate (C–S–H) and ettringite, which increases the compressive strength of the cementitious specimens. The addition of the Ss to a mixture composed of 8%PG and 8%L–B accelerates the kinetics of hydration and activates the pozzolanic reaction. The presence of C2S in the slag helps to increase the mechanical strength of the mixture B–L–PG–Ss. The compressive strength of the mixtures BL–W, BL–PG–W and BL–PG–Ss–W increases from 15 to 28 days of setting. After 28 days of setting, 8% of Sc added to the mixture 8% PG–8%L–B is responsible for an increase of the compressive strength to 0.6 MPa.

scholarly journals Hydration Characteristics of Tricalcium Aluminate in the Presence of Nano-Silica

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 199
Author(s):  
Dapeng Zheng ◽  
Manuel Monasterio ◽  
Weipeng Feng ◽  
Waiching Tang ◽  
Hongzhi Cui ◽  
...  
Keyword(s):  
Isothermal Calorimetry ◽  
Pozzolanic Reaction ◽  
Nano Silica ◽  
Hydration Kinetics ◽  
Reactive Component ◽  
Nano Sio2 ◽  
Pozzolanic Reactivity ◽  
Tricalcium Aluminate ◽  
Hydration Characteristics ◽  
Kinetics Of

Tricalcium aluminate (C3A) is the most reactive component of the Portland cement and its hydration has an important impact on the workability and early strength of concrete. Recently, nanomaterials such as nano-silica (nano-SiO2) have attracted much attention in cement-based materials because of its pozzolanic reactivity and the pore-filling effect. However, its influence on the hydration of C3A needs to be well understood. In this study, the hydration kinetics of C3A mixed with different percentages of nano-SiO2 were studied and compared with pure C3A. The hydration products were examined by different characterization techniques including XRD, XPS, and NMR spectroscopy and isothermal calorimetry analyses. The XRD results showed that the addition of nano-SiO2 promoted the conversion of the intermediate product C4AH13. The isothermal calorimetry results showed that the addition of nano-SiO2 significantly reduced the hydration exotherm rate of C3A from 0.34 to less than 0.1 mW/g. With the presence of nano-SiO2, the peaks for Q1 were observed in 29Si MAS-NMR measurements, and the content of Q1 increased from 6.74% to 30.6% when the nano-SiO2 content increased from 2 wt.% to 8 wt.%, whereas the proportion of Q4 gradually decreased from 89.1% to 63.6%. These results indicated a pozzolanic reaction provoked by the nano-SiO2 combined with aluminate structures generating C-A-S-H gel.

scholarly journals Cement-Based Renders Manufactured with Phase-Change Materials: Applications and Feasibility

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Luigi Coppola ◽  
Denny Coffetti ◽  
Sergio Lorenzi
Keyword(s):  
Compressive Strength ◽  
Phase Change ◽  
Phase Change Materials ◽  
Residential Buildings ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Hydration Kinetics ◽  
Mechanical Performances ◽  
Entrapped Air ◽  
Kinetics Of

The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM) in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.

scholarly journals Effect of Different Hydration Time on Carbonation Degree and Strength of Steel Slag Specimens Containing Zeolite

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3898
Author(s):  
Xiong Zhang ◽  
Jun Chang
Keyword(s):  
Compressive Strength ◽  
Steel Slag ◽  
Pozzolanic Reaction ◽  
Test Methods ◽  
New Mineral ◽  
Curing Time ◽  
Hydration Time ◽  
Carbonation Process ◽  
Substitution Ratio ◽  
Carbonation Curing

Steel slag partially substituted by zeolite (SZ) was beneficial for improving the compressive strength and carbonation degree of SZ specimens after a combined curing (hydration and then carbonation) process due to pozzolanic reaction between them. By previous work results, the zeolitic substitution ratios of 5 wt.% and 15 wt.% in steel slag specimens (SZ5 and SZ15) gained the optimum compressive strength and carbonation degree, respectively, after 1 day hydration and then 2 h carbonation. This study investigated the effect of previous hydration time (1, 3, 7, 14, and 196 days) on carbonation degree and strength of SZ specimens after subsequent carbonation curing. Two zeolitic substitution ratios (5 wt.% and 15 wt.%) were selected and pure steel slag specimens were also prepared as controls. Compressive strength results revealed that the optimum hydration curing time was 1 day and the optimum zeolitic substitution ratio was 5 wt.%. The pozzolanic reaction happened in SZ specimens was divided into early and late pozzolanic reaction. In the late hydration, a new mineral, monocarboaluminate (AFmc) was produced in SZ15 specimens, modifying the carbonation degree and strength further. And the mechanism of pozzolanic reaction in early and late hydration in SZ specimens was explained by several microscopic test methods.

Effect of Chemical Composition on the Properties of Reconstructed Steel Slag

2019 ◽  
Vol 944 ◽  
pp. 1163-1171
Author(s):  
Ying Xu ◽  
Qiao Ling Wang ◽  
Chen Guang Hu ◽  
Shan Shan Yang
Keyword(s):  
Compressive Strength ◽  
Steel Slag ◽  
Temperature Reconstruction ◽  
X Ray Diffraction ◽  
Technological Parameters ◽  
Iron And Steel ◽  
X Ray ◽  
Volume Stability ◽  
Cementitious Activity ◽  
Scanning Electron

The steel slag is not widely or extensively used because of its poor volume stability and low cementitious activity. In this paper, the solid waste fly ash, quicklime and slag discharged from iron and steel enterprises are used as conditioning components in the experiment. In order to improve the cementitious activity and volume stability of steel slag, the high temperature reconstruction experiment of steel slag was completed. The effects of C/S (2.50~3.14), S/A (4.5~17. 81) on the cementitious activity and volume stability of reconstructed steel slag were investigated by means of the tests of compressive strength, scanning electron microscope, X-ray diffraction, lithofacies test, stability test and so on. The results showed that the cementitious activity and volume stability of the reconstructed steel slag were improved in the higher C/S or lower S/A. The cementitious activity and volume stability of the reconstructed steel slag were improved with the increase of CaF2 content. By analyzing the cementitious activity and volume stability of the reconstructed steel slag, the optimum technological parameters are obtained as follows: C/S is 2.70 , S/A is 5.78, the content of CaF2 is 4%.

Evaluation of setting time and compressive strength of a new bone cement precursor powder containing Mg–Na–Ca

2018 ◽  
Vol 232 (10) ◽  
pp. 1017-1024 ◽  
Author(s):  
Mohammad Hossein Esnaashary ◽  
Hamid Reza Rezaie ◽  
Alireza Khavandi ◽  
Jafar Javadpour
Keyword(s):  
Compressive Strength ◽  
Bone Cement ◽  
Setting Time ◽  
Precursor Powder ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
Liquid Ratio ◽  
X Ray ◽  
The One ◽  
Kinetics Of

Taking the advantage of a novel magnesium phosphate precursor containing Na and Ca, the cementation rate of the cement, including only Mg/Mg–Na–Ca, was studied. Besides, two effective parameters, that is, calcination temperature, 650 °C and 800 °C, and powder-to-cement liquid ratio, 1 and 1.5 g/mL, were assessed. X-ray diffraction, scanning electron microscopy, ion chromatography, particle size analyser, Vicat needle and compression test were used to characterize the powders and obtained cements. The sample containing Mg–Na–Ca, calcined at 800 °C with powder-to-cement liquid ratio of 1.5, obtained the highest compressive strength, 20 MPa, but set fast. To control the kinetics of cementation, the powder containing Mg–Na–Ca calcined at 950 °C with powder-to-cement liquid ratio of 1.5 and 2 g/mL was assessed and the one with 2 g/mL set in 9 min possessing 22 MPa compressive strength was selected as optimal condition to be used as a candidate, injectable bone cement.

Influence of Metakaolin on Strength and Microstructure of Steam-Cured High-Strength Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 42-46 ◽  
Author(s):  
Jun Jie Zeng ◽  
Zhi Hong Fan ◽  
Long Chen
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Pozzolanic Reaction ◽  
Early Age ◽  
Test Results ◽  
Replacement Level ◽  
Strength Concrete ◽  
Pozzolanic Reactivity ◽  
Compressive Strength Test

The influence of metakaolin (MK) on strength and microstructure of steam-cured high-strength concrete has been investigated using compressive strength test, XRD, MIP and SEM. Three MK replacement levels were considered in the study: 5%, 10% and 15% by weight of cement. A mix double blended with 10% MK and 10% slag was prepared too. Test results have indicated that MK can increase the compressive strength of steam-cured concrete, especially at early age. Compressive strength up to 90MPa at 1 and 28 days is obtained with the incorporation of 10% MK and 10% slag. When the replacement level of MK is higher than 10%, the enhancement of strength becomes less significant. Content of Ca (OH)2 crystals is decreased while content of hydrates with Al is increased due to the pozzolanic reactivity of MK. Concrete pore structure is significantly refined and a denser hydrates structure is obtained due to the pozzolanic reaction and filler effect of MK. Meanwhile, combination of aggregate and paste is enhanced too. The improvements of strength and microstructure become more obvious when MK and slag are double incorporated.

scholarly journals The influence of curing temperature, plastic additives and polypropylene fibers on the mechanical behaviour of cementitious materials

2020 ◽  
Vol 150 ◽  
pp. 02012
Author(s):  
Mohammed Aqil ◽  
Lahcen Bahi ◽  
Latifa Ouadif ◽  
Siham Belhaj ◽  
Raounak Edderkaoui
Keyword(s):  
Compressive Strength ◽  
Mechanical Behaviour ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Curing Temperature ◽  
Polypropylene Fibers ◽  
Hydration Kinetics ◽  
Degree Of Hydration ◽  
History Of ◽  
Kinetics Of

An experimental company was carried out to better understand the influence of curing temperature on the mechanical behaviour of cementitious materials, particularly compressive strength, the study focused on two types of mortars, the first containing polypropylene fibers while the second contains a proportion of PVC-type plastic grains from industrial waste, the hydration kinetics of the different components of the formulated mortar has been characterized by the isothermal calorimetric test, thus a history of the hydration degrees has been established, Afterwards, an attempt was made to correlate the compressive strength with the evolution of the degree of hydration for the different formulations, based on the results obtained, it is clearly observable that the compressive strength evolves with the degree of hydration and that the specimen containing the polypropylene fibers has the best mechanical performance with respect to compression.

Research on Hydration Reaction of Slag-Cement Material System

2014 ◽  
Vol 629-630 ◽  
pp. 376-381
Author(s):  
Qing Wang ◽  
Zhao Yang Ding ◽  
Ning Wang ◽  
Wei Jiang ◽  
Tao Jun Wu
Keyword(s):  
Compressive Strength ◽  
Cement Composite ◽  
Hydration Reaction ◽  
Material System ◽  
Slag Cement ◽  
Hydration Kinetics ◽  
Cement Material ◽  
Cementing Material ◽  
Kinetics Of ◽  
Scanning Electron

The influence of slag dosage on the hydration kinetics of slag-cement composite cementing material system is studied. The results show that the exothermic rate of hydration decreases as the slag dosage increases or the temperature of hydration decreases. The non-evaporable water content increases at first and then decreases with the increasing of slag dosage, and reaches the maximum as slag dosage is 30%. The compressive strength decreases as slag dosage increases, the increasing rate of which is evidently before 28 days, after that it is flat or become slow. It can be seen from SEM (scanning electron microscope), in the system of slag dosage below 30%, the gel-like structures bind with crystals which make the system very compact.

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