Effect of hydrated lime on efflorescence formation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Diogo Henrique de Bem ◽  
Priscila Ongaratto Trentin ◽  
Ronaldo A. Medeiros-Junior
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Design Methodology ◽  
Hydrated Lime ◽  
Content Type ◽  
Mercury Intrusion ◽  
Lime Content ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Historical Heritage

PurposeEfflorescence formation is very common in cement-based materials. In the case of mortar, efflorescence is more studied when only Portland cement is used as a binder. However, the repair of historical heritage, as well as the construction system of some countries, usually uses mortars composed of hydrated lime and Portland cement. This study aims to determine the influence of the hydrated lime content on the incidence of efflorescence in mortars.Design/methodology/approachMortars with 0%, 50%, and 100% lime/cement ratio were studied, using three different methods to accelerate efflorescence formation. The surface area of mortars affected by efflorescence was quantified by analysis using image software. Also, analysis of mercury intrusion porosity test, flexural tensile, compressive strength, absorption of water by capillarity, porosity, XRD and TGA was performed.FindingsMore efflorescence in mortars with a higher amount of lime in their composition was observed. The results show that the increase in the lime content reduces the flexural tensile and the compressive strength and increased the absorption of water by capillarity and the porosity of the mortars. The material formed by the efflorescence was calcium carbonate, proven by microstructural tests.Originality/valueThe results of greater efflorescence formation in mortars with lime are important to alert users who apply this type of material. Some type of protection must be done more rigorously for lime-cement mortars, especially concerning contact with water, since efflorescence tends to be faster for this type of material.

scholarly journals Ultrasonic Pulse Velocity—Compressive Strength Relationship for Portland Cement Mortars Cured at Different Conditions

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 133 ◽  
Author(s):  
Esteban Estévez ◽  
Domingo Alfonso Martín ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Internal Quality ◽  
Curing Conditions ◽  
Linear Relationships ◽  
Cement Mortars ◽  
Strength Relationship

The purpose of this paper is to establish some correlations between the main technical parameter with regard to the cement-based materials technology, the 28-day compressive strength, and ultrasonic pulse velocity of standard mortar samples cured at three different conditions—(i) under water at 22 °C; (ii) climatic chamber at 95% RH and 22 °C; (iii) lab ambient, 50% RH, and 22 °C—and after five curing periods of 1, 2, 7, 14, and 28 days. Good correlations for each curing conditions were obtained. All the positive linear relationships showed better R2 than exponential ones. These findings may promote the use of ultrasonic pulse velocity for the estimation of the 28-day compressive strength of standard Portland cement samples within the factory internal quality control.

The usage of ultra-fine cement as an admixture to increase the compressive strength of Portland cement mortars

2013 ◽  
Vol 42 ◽  
pp. 152-160 ◽  
Author(s):  
Juan Carlos Arteaga-Arcos ◽  
Obed Arnoldo Chimal-Valencia ◽  
Hernani Tiago Yee-Madeira ◽  
Sebastián Díaz de la Torre
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortars

Performance of Cement Systems with Nano-SiO2 Particles Produced Using Sol-gel Method

2010 ◽  
Vol 1276 ◽  
Author(s):  
Konstantin Sobolev ◽  
Ismael Flores ◽  
Leticia M. Torres ◽  
Enrique L. Cuellar ◽  
Pedro L. Valdez ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Portland Cement ◽  
High Speed ◽  
Essential Role ◽  
Sol Gel ◽  
Strength Development ◽  
Cement Mortars ◽  
Effective Dispersion ◽  
Dispersion Of Nanoparticles

AbstractThe reported research examines the effect of 5–70 nm SiO2 nanoparticles on the mechani-cal properties of nanocement materials. The strength development of portland cement with nano-SiO2 and superplasticizing admixture is investigated. Experimental results demonstrate an in-crease in the compressive strength of mortars with SiO2nanoparticles. The distribution of nano-SiO2 particles within the cement paste plays an essential role and governs the overall perfor-mance of these products. Therefore, the addition of a superplasticizer is proposed to facilitate the distribution of nano-SiO2 particles. The application of effective superplasticizer and high-speed dispergation are found to be very effective dispersion techniques that improve the strength of su-perplasticized portland cement mortars, reaching up to 63.9 MPa and 95.9 MPa after aging dur-ing 1 and 28 days, respectively. These values compare favorably with the observed compressive strengths of reference portland cement mortars of 53.3 MPa and 86.1 MPa. It is concluded that the effective dispersion of nanoparticles is essential to obtain the composite materials with im-proved performance.

scholarly journals Anticipating the Compressive Strength of Hydrated Lime Cement Concrete Using Artificial Neural Network Model

2018 ◽  
Vol 4 (12) ◽  
pp. 3005 ◽  
Author(s):  
Chioma Temitope Gloria Awodiji ◽  
Davis Ogbonnaya Onwuka ◽  
Chinenye Okere ◽  
Owus Ibearugbulem
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Compressive Strength ◽  
Portland Cement ◽  
Neural Network Model ◽  
Artificial Neural Network Model ◽  
Ordinary Portland Cement ◽  
Hydrated Lime ◽  
Cement Concrete ◽  
Data Set

In this research work, the levernberg Marquardt back propagation neural network was adequately trained to understand the relationship between the 28th day compressive strength values of hydrated lime cement concrete and their corresponding mix ratios with respect to curing age. Data used for the study were generated experimentally. A total of a hundred and fourteen (114) training data set were presented to the network. Eighty (80) of these were used for training the network, seventeen (17) were used for validation, and another seventeen (17) were used for testing the network's performance. Six (6) data set were left out and later used to test the adequacy of the network predictions. The outcome of results of the created network was close to that of the experimental efforts. The lowest and highest correlation coefficient recorded for all data samples used for developing the network were 0.901 and 0.984 for the test and training samples respectively. These values were close to 1. T-value obtained from the adequacy test carried out between experimental and model generated data was 1.437. This is less than 2.064, which is the T values from statistical table at 95% confidence limit. These results proved that the network made reliable predictions. Maximum compressive strength achieved from experimental works was 30.83N/mm2 at a water-cement ratio of 0.562 and a percentage replacement of ordinary portland cement with hydrated lime of 18.75%. Generally, for hydrated lime to be used in making structural concrete, ordinary portland cement percentage replacement with hydrated lime must not be up to 30%. With the use of the developed artificial neural network model, mix design procedure for hydrated lime cement concrete can be carried out with lesser time and energy requirements, when compared to the traditional method. This is because, the need to prepare trial mixes that will be cured, and tested in the laboratory, will no longer be required.

scholarly journals Study on the Pore Structure Characteristics of Ferronickel-Slag-Mixed Ternary-Blended Cement

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4863
Author(s):  
Won Jung Cho ◽  
Min Jae Kim ◽  
Ji Seok Kim
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Chloride Transport ◽  
Blended Cement ◽  
Cement Matrix ◽  
X Ray ◽  
Mercury Intrusion ◽  
Ferronickel Slag

Pore structure development in Portland cement, fly ash, or/and ferronickel slag (FNS) was investigated using mercury intrusion porosimetry and X-ray CT tomography. The progress of hydration was observed using X-ray diffraction (XRD) analysis and compressive strength while durability of concrete was monitored by chloride penetration resistance and chloride profiles. Mercury intrusion porosimetry (MIP) results suggested that the blended cement had a higher porosity while lower critical pore size. The major reason to this increased porosity was the formation of meso and micro pores compared to ordinary Portland cement (OPC). In terms of chloride transport, replaced cement, especially ternary-blended cement had higher resistance to chloride transport and exhibited slightly lower development of compressive strength. X-ray CT tomography shows that the influence of pore structure of ternary-blended cement on the ionic transport was strongly related to the pore connectivity of cement matrix.

Research on the Strengthening Effect of Phosphorus Slag Powder on Cement-Based Materials

2009 ◽  
Vol 405-406 ◽  
pp. 356-360 ◽  
Author(s):  
Dong Mei Liu ◽  
Kun He Fang ◽  
Hua Shan Yang
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Hydration ◽  
Hydration Product ◽  
Strengthening Effect ◽  
Early Hydration ◽  
Double Excitation ◽  
Slag Powder ◽  
Cement Mortars ◽  
Cement Based Materials

The strengthening effect of phosphorus slag powder (PSP) in cement-based materials was researched by model of strengthening effect of mineral admixes, and the mechanism of strengthening effect of PSP was also studied by SEM. The results indicate that, in early hydration period, the strengthening effect of PSP on strength of cement mortars is zero. At 90 days, strengthening effect has been exerted, and increases with the amount of PSP when that is no more than 40%, but decreases with larger content of PSP. At 180 days, the strengthening effect was further enhanced, the greater the amount of PSP, the greater its effect. For compressive strength of cement mortars, the strengthening effect of PSP is more than that of PSP on flexural strength. The results analyses of SEM show that, strengthening effect of PSP mainly come from its pozzolana reaction. With double excitation of cement hydration product hydroxide and gypsum, the low alkalinity C-S-H was produced.

Compressive strength of portland cement mortars and concretes

1915 ◽  
Vol 180 (5) ◽  
pp. 608-613 ◽  
Author(s):  
R.J. Wig ◽  
G.M. Williams ◽  
E.R. Gates
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortars

Experimental investigation on the compressive strength of PFGP-covered concretes exposed to high temperature

2019 ◽  
Vol 10 (4) ◽  
pp. 399-410
Author(s):  
Amir Hamzeh Keykha
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
High Temperature ◽  
Design Methodology ◽  
Polypropylene Fiber ◽  
Content Type ◽  
Gypsum Plaster ◽  
Compressive Strength Of Concrete

Purpose This study aims to investigate the effect of high temperature (600°C) on the compressive strength of concrete covered with a mixture of polypropylene fiber and gypsum plaster (PFGP). Design/methodology/approach To study the compressive strength of concrete specimens exposed to temperature, 16 cubic specimens (size: 150 mm × 150 mm × 150 mm) were made. After 28 days of processing and gaining the required strength of specimens, first, polypropylene fiber was mixed with gypsum plaster (CaSO4.2H2O) and then the concrete specimens were covered with this mixture. To cover the concrete specimens with the PFGP, the used PFGP thickness was 15 mm or 25 mm. The polypropylene rates mixed with the gypsum plaster were 1, 3 and 5 per cent. A total of 14 specimens, 12 of which were covered with PFGP, were exposed to high temperature in two target times of 90 and 180 min. Findings The results show that the PFGP as covering materials can improve the compressive strength lost because of the heating of the concrete specimens. The results also show that the presence of polypropylene fiber in gypsum plaster has the effect on the compressive strength lost because of the heating of the PFGP-covered concrete. The cover of PFGP having 3 per cent polypropylene fiber had the best effect on remained strength of the specimens. Originality/value The cover of PFGP having 3 per cent polypropylene fiber has the best effect on remained strength of the PFGP covered specimens exposed to temperature.

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