Use of X-ray diffraction to quantify amorphous supplementary cementitious materials in anhydrous and hydrated blended cements

2014 ◽  
Vol 64 ◽  
pp. 89-98 ◽  
Author(s):  
R. Snellings ◽  
A. Salze ◽  
K.L. Scrivener
Keyword(s):  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blended Cements

scholarly journals Durability of Ternary Cements Based on New Supplementary Cementitious Materials from Industrial Waste

2021 ◽  
Vol 11 (13) ◽  
pp. 5977
Author(s):  
Isabel Fuencisla Sáez del Bosque ◽  
María Isabel Sánchez de Rojas ◽  
Gabriel Medina ◽  
Sara Barcala ◽  
César Medina
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Replacement Ratio ◽  
X Ray ◽  
Blended Cements ◽  
Optimal Replacement ◽  
Bearing Materials

Cement-based materials decay with exposure to aggressive agents, a development that raises infrastructure operation and maintenance costs substantially. This paper analyses the inclusion of ultrafine construction and demolition (UC&DW) and biomass-fuelled power plant (BA) waste as pozzolanic additions to cement in pursuit of more sustainable and eco-respectful binders and assesses the durability of the end materials when exposed to seawater, chlorides (0.5 M NaCl) or sulphates (0.3 M Na2SO4). The effect of adding silica fume (SF) at a replacement ratio of 5% was also analysed. Durability was determined using the methodology proposed by Koch and Steinegger, whilst microstructural changes were monitored with mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for a fuller understanding of decay processes. According to the findings, the new blended cements containing 20%UC&DW + 10%BA or 20%UC&DW + 20%BA + 5%SF resist the attack by the aggressive media studied, with a 56-d corrosion index of over 0.7. The composition of the reaction products generated with the attack is essentially the same in OPC and the SCM-bearing materials. The results show that the optimal replacement ratio for SCM is 30%.

Pozzolanic Reaction of Supplementary Cementitious Materials and Its Effects on the Strength of Mass Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 505-511 ◽  
Author(s):  
Hua Shan Yang ◽  
Kun He Fang ◽  
Sheng Jin Tu
Keyword(s):  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Supplementary Cementitious Materials ◽  
Mass Concrete ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slag Powder ◽  
Phosphorous Slag ◽  
Better Than

The present study aims to investigate the opportunity to largely substitute low heat Portland cement of mass concrete with supplementary cementitious materials. The pozzolanic reaction of two types of supplementary cementitious materials, phosphorous slag powder and fly ash , were determined by X-ray diffraction, differential thermal analysis–thermogravimetry and scanning electron microscopy from 28 to 90 days. The properties of mortar and mass concrete containing 30% of supplementary cementitious materials were also investigated. Results showed that supplementary cementitious materials could decrease the amount of calcium hydroxide, fill the capillary pores, thus making the mortar and mass concrete more compact and durable. Long-term strength of mass concrete containing 30% of supplementary cementitious materials were comparable (or even better) than the control concrete (without supplementary cementitious materials) at constant workability, while the Young’s modulus was lower than the control concrete.

scholarly journals Measurement of Pozzolanic Activity Index of Scoria, Pumice, and Rice Husk Ash as Potential Supplementary Cementitious Materials for Portland Cement

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hieronimi A. Mboya ◽  
Cecil K. King’ondu ◽  
Karoli N. Njau ◽  
Alex L. Mrema
Keyword(s):  
Portland Cement ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Activity Index ◽  
Cementitious Materials ◽  
Pozzolanic Activity ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Setting Times

This work investigated the properties of scoria and pumice as supplementary cementitious materials (SCMs) for Portland cement and compared to those of rice husk ash (RHA). X-ray fluorescence, X-ray diffraction, and pozzolanic activity index (PAI) tests confirmed the suitability of these two materials as potential SCMs. Scoria and RHA samples achieved over 75% PAI at 7 days whereas pumice did this after 28 days. Initial and final mean setting times observed for the composite cement blended with these materials were 166 and 285 min, respectively. These setting times are longer than that of ordinary Portland cement but shorter compared to that of common Portland pozzolana cement. The ultimate mean compressive strengths achieved at 28 days of curing were 42.5, 44.8, and 43.0 MPa for scoria, pumice, and RHA, respectively, signifying that these materials are good SCMs. Higher fineness yielded higher ultimate mean strength. For instance, a scoria sample with a fineness of 575 m2/kg achieved the strength of 52.2 MPa after 28 days.

scholarly journals The Influence of Chemical Activators on the Hydration Behavior and Technical Properties of Calcium Sulfoaluminate Cements Blended with Ground Granulated Blast Furnace Slags

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 268
Author(s):  
Milena Marroccoli ◽  
Antonio Telesca
Keyword(s):  
Blast Furnace ◽  
Co2 Emissions ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
Cement Production ◽  
Blended Cements ◽  
Calcium Sulfoaluminate ◽  
Technical Performance ◽  
Technical Properties

The manufacture of Ordinary Portland cement (OPC) generates around 8% of the global CO2 emissions related to human activities. The last 20 years have seen considerable efforts in the research and development of methods to lower the carbon footprint associated with cement production. Specific focus has been on limiting the use of OPC and employing alternative binders, such as calcium sulfoaluminate (CSA) cements, namely special hydraulic binders obtained from non-Portland clinkers. CSA cements could be considered a valuable OPC alternative thanks to their distinctive composition and technical performance and the reduced environmental impact of their manufacturing process. To additionally reduce CO2 emissions, CSA cements can also be blended with supplementary cementitious materials. This paper investigates the influence of two separately added chemical activators (NaOH or Na2CO3) on the technical properties and hydration behavior of four CSA blended cements obtained by adding to a plain CSA cement two different ground granulated blast furnace slags. Differential thermal-thermogravimetric, X-ray diffraction and mercury intrusion porosimetry analyses were done, along with shrinkage/expansion and compressive strength measurements.

scholarly journals Use of Potabilized Water Sludge in the Production of Low-Energy Blended Calcium Sulfoaluminate Cements

2021 ◽  
Vol 11 (4) ◽  
pp. 1679
Author(s):  
Antonio Telesca ◽  
Neluta Ibris ◽  
Milena Marroccoli
Keyword(s):  
Co2 Emissions ◽  
Carbon Footprint ◽  
Energy Demand ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
Hydration Properties ◽  
Blended Cements ◽  
Calcium Sulfoaluminate ◽  
Pozzolanic Material

Ordinary Portland cement (OPC) manufacture determines about 8% of the global anthropogenic CO2 emissions. This has led to both the cement producers and the scientific community to develop new cementitious materials with a reduced carbon footprint. Calcium sulfoaluminate (CSA) cements are special hydraulic binders from non-Portland clinkers; they represent an important alternative to OPC due to their peculiar composition and significantly lower impact on the environment. CSA cements contain less limestone and require lower synthesis temperatures, which means a reduced kiln thermal energy demand and lower CO2 emissions. CSA cements can also be mixed with supplementary cementitious materials (SCMs) which further reduce the carbon footprint. This article was aimed at evaluating the possibility of using different amounts (20 and 35% by mass) of water potabilization sludges (WPSs) as SCM in CSA-blended cements. WPSs were treated thermally (TT) at 700° in order to obtain an industrial pozzolanic material. The hydration properties and the technical behavior of two different CSA-blended cements were investigated using differential thermal–thermogravimetric and X-ray diffraction analyses, mercury intrusion porosimetry, shrinkage/expansion and compressive strength measurements. The results showed that CSA binders containing 20% by mass of TTWPSs exhibited technological properties similar to those relating to plain CSA cement and were characterized by more pronounced eco-friendly features.

Sedimentary Clays as Geopolymer Precursor

2018 ◽  
Vol 39 ◽  
pp. 97-111
Author(s):  
F. Mostefa ◽  
Nasr Eddine Bouhamou ◽  
H.A. Mesbah ◽  
Salima Aggoun ◽  
D. Mekhatria
Keyword(s):  
Sodium Hydroxide ◽  
Mineralogical Composition ◽  
Cementitious Materials ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Calcination Time ◽  
Calorimetric Analysis ◽  
X Ray ◽  
Before And After ◽  
Mechanical Performances

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

scholarly journals Influence of Milling Techniques on the Performance of Wheat Straw Ash in Cement Composites

2020 ◽  
Vol 10 (10) ◽  
pp. 3511
Author(s):  
Abdul Qudoos ◽  
Ehsanullah Kakar ◽  
Atta ur Rehman ◽  
In Kyu Jeon ◽  
Hong Gi Kim
Keyword(s):  
Particle Size ◽  
Wheat Straw ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hydration Reaction ◽  
Cement Composites ◽  
Cement Production ◽  
X Ray ◽  
Worldwide Production ◽  
Straw Ash

The worldwide production of cement is growing every year due to its increased use in the construction. Cement production is affiliated with an environmental concern as it contributes to the CO2 emissions. It is imperative to reduce the cement production by incorporating supplementary cementitious materials in the cement composites. In this research study, wheat straw ash (WSA) was used as an alternate of ordinary Portland cement. The ash was ground separately with a ball mill and a disintegrator mill as well as with a combination of both to enhance its pozzolanic efficiency. Mortar and paste specimens were made by substituting cement with WSA (20% by weight). Ash specimens were examined in terms of particle size distribution, X-ray diffraction, and X-ray fluorescence analyses. The performance of the ash specimens in cement composites was examined via compressive and flexural strengths, and ultrasonic pulse velocity (UPV) tests. Isothermal calorimetric, thermogravimetric analyses (TGA), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) were also employed on the specimens. The results revealed that the particle size of the wheat straw ash specimens significantly reduced and specific surface area enhanced when ground with a combination of both milling techniques. Cement composites made with this type of ash demonstrated improved mechanical and physical properties, accelerated hydration reaction at the early ages, reduce calcium hydroxide content at the later ages, and densified microstructure.

scholarly journals Sustainable low-carbon binders and concretes

2020 ◽  
Vol 166 ◽  
pp. 06007
Author(s):  
Myroslav Sanytsky ◽  
Tetiana Kropyvnytska ◽  
Stanislav Fic ◽  
Hanna Ivashchyshyn
Keyword(s):  
Activity Index ◽  
Chemical Properties ◽  
High Volume ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Cement Matrix ◽  
Low Carbon ◽  
Blended Cements ◽  
Physical And Chemical

Sustainable development depends on a consistency of interests, social, ecological and economic, and that the interests are evaluated in a balanced manner. In order to reduce CO2 emissions, the conception of decreasing clinker factor and increasing the role of supplementary cementitious materials (SCMs) in the cementitious materials has high economical and environmental efficiency. The performance of clinkerefficient blended cements with supplementary cementitious materials were examined. The influence of superfine zeolite with increased surface energy on the physical and chemical properties of low-carbon blended cements is shown. Increasing the dispersion of cementitious materials contributes to the growth of their strength activity index due to compaction of cement matrix and pozzolanic reactions in unclincker part. In consequence of the early structure formation and the directed formation of the microstructure of the cement matrix is solving the problem of obtaining clinker-efficient concretes. Shown that low-carbon blended cements with high volume of SCMs are suitable, in principle, for producing structural concretes.

Preparation and Targeted Regulation of Microbial Induced Mineralized Products

2020 ◽  
Vol 12 (1) ◽  
pp. 116-123
Author(s):  
Haihe Yi ◽  
Qiwei Zhan ◽  
Chunxiang Qian
Keyword(s):  
Ph Value ◽  
Cementitious Materials ◽  
Stable Phase ◽  
Logarithmic Phase ◽  
Culture Solution ◽  
Extracellular Production ◽  
X Ray Diffraction ◽  
X Ray ◽  
Culture Process ◽  
Growth And Reproduction

Microbial induced mineralization is an effective method to prepare green cementitious materials, which has the characteristics of ecological and environmental protection. In this study, preparation and targeting regulation of mineralized products by Bacillus lysine induced was investigated. Law of growth and reproduction was studied via change curves of concentration and pH value of culture solution in the culture process. Four periods, included retardation phase, logarithmic phase, stable phase and decline phase, were verified. The pH value of culture solution was on the rise throughout the culture process, which increased from 7 to 8.1. Characteristics of enzyme production were explored by the deposition of mineralized products in different systems, and the way of extracellular production enzyme was determined. The composition and microstructure of mineralized products were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray spectroscopy (EDS). The mineralized products were characterized as calcite, and mineralized products in the culture solution had higher crystallinity. Finally, targeting regulation of temperature on mineralized products was conducted. At the low temperature, mineralization efficiency was higher, and the structure of mineralized products was more favorable.

Magnesium Phosphate Cement with Large Volume of Fly Ash

2012 ◽  
Vol 174-177 ◽  
pp. 802-805 ◽  
Author(s):  
Zhu Ding ◽  
Bi Qin Dong ◽  
Feng Xing
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Large Volume ◽  
Sodium Phosphate ◽  
Cement Mortar ◽  
Cementitious Materials ◽  
X Ray Diffraction ◽  
Monoammonium Phosphate ◽  
Ammonia Gas ◽  
X Ray

The accumulation of fly ash leads to severe problems in ecological environments. Various ways to excite the activity of fly ash in Portland cement based cementitious materials have been carried out for many years. In the present study, effect of large volume of fly ash in phosphate cement was studied. Dead burned magnesia, two phosphates (monoammonium phosphate and monosodium phosphate), and fly ash were used. The fabricated cement mortar specimens with different fly ash dosages were cured for 28 days in the lab air. Compressive strength was determined in 1d, 3d, 7d and 28d respectively. It is showed the compressive strength reduced with increase of fly ash content and increased with the curing time. After cured 28 days, the compressive strength of cement mortar developed to14MPa, when 80% fly ash was used. The reaction product, Na2HPO4•17H2O was found by X-ray diffraction analysis in sodium phosphate based cement. No ammonia gas was emitted and large volume of fly ash can be used in cement prepared from sodium phosphate. It is a new environmentally friendly cement material.

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