scholarly journals Effects of Mud from a Zinc-plating Plant and Zeolite Saturated with Zinc on Portland Cement Hydration and Properties of Hardened Cement Pastes

2017 ◽  
Vol 30 (4) ◽  
pp. 401-409 ◽  
Author(s):  
D. Barbir
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Zinc Plating ◽  
Hardened Cement Pastes ◽  
Plating Plant ◽  
Portland Cement Hydration

scholarly journals Effect of Mineral Composition and w/c Ratios to the Growth of AFt during Cement Hydration by In-Situ Powder X-ray Diffraction Analysis

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4963
Author(s):  
Bo Chen ◽  
Yongming Zhang ◽  
Qing Chen ◽  
Fei Yang ◽  
Xianping Liu ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Hardened Cement ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Hardened Cement Pastes ◽  
Maximum Content ◽  
Very High

AFt is one of the major products at the early stage of cement hydration. It is an important product that influences the performance of the fresh and hardened cement pastes such as the setting time. However, there is a lack of detailed investigation on the growth of AFt in the cement pastes with a long-time scale. In this work, we reported a detailed analysis by using in-situ powder X-ray diffraction (XRD) on the growth of AFt in the cement pastes during hydration. Samples of the hydrated ordinary Portland cement (OPC) and another locally produced Portland cement with very high tricalcium silicate (C3S) content with different water–cement (w/c) ratios were investigated continually till they were hydrated for about 270 days by powder XRD. The work shows that during Portland cement hydration, the AFt reaches its maximum content with very high speed within about 24 h, which is influenced by the content of C3S in the raw cement samples and the w/c ratios of the cement pastes. Once the maximum content of AFt was reached, it decreases very fast within the following couple of days, and then decreases slowly and finally reaches a stable level at the late stage of hydration. The results also present that a lower w/c ratio is beneficial to the formation of AFt and the conversion of AFt to AFm as well. While higher w/c ratios are favorable for the AFt to remain stable in the hardened cement pastes.

scholarly journals Effect of Some Acrylate—Poly(Ethylene Glycol) Copolymers as Superplasticizers on the Mechanical and Surface Properties of Portland Cement Pastes

2005 ◽  
Vol 23 (3) ◽  
pp. 245-254 ◽  
Author(s):  
S.A. Abo-El-Enein ◽  
S. Hanafi ◽  
F.I. El-Hosiny ◽  
El-Said H.M. El-Mosallamy ◽  
M.S. Amin
Keyword(s):  
Ethylene Glycol ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Mechanical Characteristics ◽  
Hardened Cement ◽  
Poly Ethylene Glycol ◽  
Cement Pastes ◽  
Surface Areas ◽  
Poly Ethylene ◽  
Hardened Cement Pastes

Ordinary Portland cement (OPC) pastes with added superplasticizer were made using water/cement weight ratios of standard consistency. Three types of superplasticizer based on acrylate—poly(ethylene glycol) copolymers were used. The pastes were hydrated for various time lengths and the mechanical characteristics of the hardened cement pastes were studied and related to their pore structures. It was found that the addition of the superplasticizers to OPC improved the mechanical properties of the hardened pastes for all hydration lengths. The addition of such superplasticizers to OPC resulted in a decrease in the specific surface areas and total pore volumes of the hardened superplasticized cement pastes relative to the corresponding hardened neat cement pastes.

Composites of Portland Cement and Natural Polymers

2005 ◽  
Vol 498-499 ◽  
pp. 407-412 ◽  
Author(s):  
Ulisses Targino Bezerra ◽  
Antonio Eduardo Martinelli ◽  
D.M.A. Melo ◽  
D.M. Henrique ◽  
E.M. Rodrigues ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Environmentally Friendly ◽  
Hardened Cement ◽  
Oil Well ◽  
Natural Polymer ◽  
Natural Polymers ◽  
Cement Pastes ◽  
Preliminary Results ◽  
Hardened Cement Pastes

The tensile strength of Portland cement may be increased by additional reinforcement. This is usually accomplished by means of steel rods, fibers or particles, which are mixed to the slurry. In an attempt of increasing toughness and tensile strength of hardened cement pastes, the present work describes the behavior of composites consisting of Portland reinforced by natural polymer particles for oil well cementing. The main purpose of the study was to select plastic and environmentally friendly powdered materials capable of filling the typical porosity developed on hardened Portland cement. Preliminary results suggested that the tensile strength of plain Portland hardened slurries could be increased by as much as 40% by adding 10% of reinforcement.

Influence of Physicochemical Properties of Sugarcane Bagasse Ash (SCBA) in Portland Cement Hydration

2018 ◽  
Vol 765 ◽  
pp. 324-328
Author(s):  
Tiago Assunção Santos ◽  
José da Silva Andrade Neto ◽  
Vitor Souza Santos ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Cement Hydration ◽  
New Technologies ◽  
Pozzolanic Reaction ◽  
Cement Industry ◽  
Partial Replacement ◽  
Cement Pastes ◽  
Sugarcane Bagasse Ash ◽  
Portland Cement Hydration

Due to the concern with the environmental impacts caused by the gases emitted by the cement industry and by the inadequate disposal of wastes generated in the sugar-alcohol industry, such as sugarcane bagasse ash (SCBA), a search for the development of new technologies, which are less aggressive to the environment and that propose feasible alternatives, began in order to reuse these wastes properly. Among these alternatives is the reuse of SCBA as partial replacement to cement or as addition to cementitious matrices. In this way, the present research has the objective of analyzing the influence of SCBA obtained by the calcination of sugarcane bagasse (SCB), at 600°C, in the process of Portland cement hydration. Initially, the SCBA was characterized physically, chemically and mineralogically, and then cement pastes with 20% and 35% substitution contents were elaborated, besides the reference paste, which were analyzed through X-ray diffraction (XRD) and thermogravimetric (TG) techniques. The results obtained show that there is a consumption of portlandite as a consequence of the use of SCBA, evidencing the pozolanicity of these ashes. In the pastes with 35% substitution content, there was an intense consumption of the portlandite, indicating, in this proportion, the pozzolanic reaction was more intense.

Characterisation of Portland Cement Hydration by Electron Optical Techniques

1983 ◽  
Vol 31 ◽  
Author(s):  
Karen L. Scrivener ◽  
P. L. Pratt
Keyword(s):  
Electron Microscopy ◽  
Portland Cement ◽  
Cement Hydration ◽  
Ion Beam ◽  
Optical Techniques ◽  
Cement Pastes ◽  
The Past ◽  
Environmental Cell ◽  
Study Of Fracture Surfaces ◽  
Portland Cement Hydration

ABSTRACTIn the past the application of electron microscopy to cement hydration has been limited largely to the study of fracture surfaces in SEM, of ground cement in TEM and of polished sections in EMPA. Consequently the microstructure of bulk cement pastes is, as yet, ambiguous.The present work shows how techniques not previously used in the study of cement, an environmental cell on HVEM, preparation of ion beam thinned foils for STEM and BEI of polished surfaces in SEM, can give a more detailed view of the development of morphology in hydrating cement. Using a combination of electron optical techniques together with other methods a detailed characterisation of cement hydration can be made.

OPTIMAL CRITERIA OF ALGERIAN BLENDED CEMENT USING LIMESTONE FINES/ALŽYRIETIŠKAS MIŠRUSIS CEMENTAS SU MALTU KALKAKMENIU

2008 ◽  
Vol 14 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Z’hor Guemmadi ◽  
Musa Resheidat ◽  
Hacéne Houari ◽  
Belkacem Toumi
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Blended Cement ◽  
Total Porosity ◽  
Hardened Cement ◽  
Compact Structure ◽  
Limestone Filler ◽  
Cement Pastes ◽  
Limestone Fines ◽  
Hardened Cement Pastes

The effect of substitution of Portland cement by limestone up to 40% as well as its fineness on the physico‐mechanical properties of fresh and hardened cement pastes is studied. The binder was prepared by substitution of cement by limestone filler. Fillers were chosen of various particle sizes and with percentages from 5 to 40. Test results revealed that the replacement of Portland cement by the finest filler of limestone slightly decreases the consistency and the setting times (initial and final). The total porosity decreases and accordingly the compressive strength is improved with the content and fines of limestone. Although limestone has a little accelerating effect on the hydration process of Portland cement, but acts only as a filler reducing the porosity due to its compact structure, in which the compressive strength of the hardened cement paste is enhanced. The XRD and DTA analyses of samples cured up to 28 days showed that this amelioration is due to formation of new hydrated compounds. It is concluded that an addition of finely ground limestone filler only up to 15% gives a better strength. Santrauka Tirtos šviežios ir sukietėjusios cementinės tešlos, kurioje iki 40 % cemento pakeista įvairaus smulkumo maltu kalkakmeniu, savybės. Rišiklis buvo paruoštas dalį cemento pakeitus maltu kalkakmenio užpildu. Užpildo dalelės buvo įvairaus dydžio, o jų kiekis buvo keičiamas nuo 5 % iki 40 %. Tyrimai parodė, kad priedas leidžia sumažinti vandens kiekį, reikalingą tos pačios konsistencijos mišiniui gauti, taip pat cemento rišimosi pradžiai ir pabaigai paankstinti. Sumažėja cementinio akmens suminis poringumas ir atitinkamai padidėja stipris gniuždant cementinio akmens, kuriame yra kalkakmenio priedų. Nors kalkakmenio priedas nedaug pagreitina portlandcemenčio hidratacijos procesą, tačiau veikia kaip užpildas, sutankinantis struktūrą, dėl to labai padidėja sukietėjusio cementinio akmens stipris gniuždant. Bandinių, išlaikytų 28 dienas, rentgenostruktūrinė ir diferencinė terminė analizė parodė, kad pagerėjimas yra dėl susidariusių naujadarų. Apibendrinant galima teigti, kad 15 % malto kalkakmenio priedas turi didžiausią įtaką stiprumo rezultatams.

Effect of Waste Glass on Portland Cement Hydration Process

2021 ◽  
Vol 325 ◽  
pp. 9-20
Author(s):  
Evaldas Serelis ◽  
Vitoldas Vaitkevicius
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Glass Powder ◽  
Cement Hydration ◽  
Test Methods ◽  
Waste Glass ◽  
Test Method ◽  
Hydration Process ◽  
Hardened Cement ◽  
Portland Cement Hydration

Glass is an amorphous material, which could be a good pozzolanic material and can be beneficial in compressive strength gain. However, if waste of glass powder has undesirable contaminations (aluminium, clay impurities, sulphates, etc.) it can negatively affect hydration process. In the research were used two types of waste glass (with and without harmful impurities). Waste glass shards were obtained from a local waste recycling plant and its properties were investigated in the Portland cement hydration process. Properties of waste glass were analysed by SEM, XRD test methods, pozzolanicity of glass powder was investigated by Chappelle test method. The hydration process of Portland cement was researched by the semi-adiabatic test method and XRD analysis. Properties of hardened cement paste was analysed by: density, flexural and compressive strength test methods The main aim of this research is to analyse waste glass, which after primary cleaning is not suitable for secondary reuse and investigate its suitability in cement-based systems.

scholarly journals Studies of Surface Area and Pore Structure on Portland Cement Produced in Bajil and Amran, Yemen

2008 ◽  
Vol 13 ◽  
pp. 13
Author(s):  
A.M. Saad ◽  
Abdul-Basit A. Saleh ◽  
Fatima A. Al-Kadri ◽  
Abdulla S. Babaqi ◽  
Abdulla A. Basissa ◽  
...  
Keyword(s):  
Portland Cement ◽  
Pore Structure ◽  
Hysteresis Loops ◽  
Hardened Cement ◽  
Pore System ◽  
Nitrogen Gas ◽  
Time Intervals ◽  
Cement Pastes ◽  
Adsorption Desorption ◽  
Hardened Cement Pastes

Portland cement pastes of various porosities were prepared using water/cement ratios of 0.30, 0.35, 0.40, 0.45, 0.50 and 0.55; and were hydrated for various time intervals ranging from 0.021 to 28 days.  Pore structure and VL–t plots (plots of volume vs. thickness) of the hardened cement pastes were measured using nitrogen gas as the adsorbate. The results were found to be related to the mechanism of hydration as controlled by the pore system of the hardened pastes. Type ІІ adsorption isotherms of nitrogen were obtained for all hardened cement pastes. The adsorption-desorption isotherms indicated the existence of closed hysteresis loops for most of the investigated samples and in some other cases, these isotherms were fully reversible.  

Influence of superplasticizers on the course of Portland cement hydration

2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Pavel Šiler ◽  
Iva Kolářová ◽  
Josef Krátký ◽  
Jaromír Havlica ◽  
Jiří Brandštetr
Keyword(s):  
Portland Cement ◽  
Heat Effect ◽  
Cement Hydration ◽  
Heat Evolution ◽  
Total Heat ◽  
Hydration Heat ◽  
Cement Pastes ◽  
Portland Cement Hydration

AbstractA multicell isoperibolic — semiadiabatic calorimeter was used for the measurement of temperature and the determination of the hydration heat evolution at earlier period of cement pastes setting and hardening. The measurements were aimed at the determination of the effect of superplasticizers (SPs) on the course of the Portland cement hydration. Commercial polycarboxylate SP was added to the mixtures and the heat effect was measured. With the increasing content of SP, the hydration temperature increased up to a certain value and then decreased. In case of a sufficient amount of water in the mixture to achieve complete hydration of cement, samples with the highest values of the maximum hydration temperature reached the highest values of the released total heat. If there is not a sufficient amount of water to achieve complete hydration, the samples with the highest values of the maximum hydration temperature reach the lowest values of the released total heat.

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