Retarding Action of Various Lead (II) Salts on Setting of Portland Cement

2018 ◽  
Vol 760 ◽  
pp. 43-48
Author(s):  
Martin Keppert
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Hydration ◽  
Setting Time ◽  
Lead Sulfate ◽  
Cementitious Material ◽  
Secondary Product ◽  
Experimental Conditions ◽  
Anion Effect ◽  
High Instability

Lead is an example of heavy metal, which influences the course of silicate cement hydration resulting to retardation of setting and hardening. This topic become of importance when a cementitious material is intended to be used as solidification/stabilization matrix for a waste or secondary product containing some lead species. There are literature data on the effect of Pb retarding action but they are incomparable each other due to uneven experimental conditions, used Pb salts, types of cement etc. The present paper aims to describe influence of various lead(II) compounds (nitrate, sulfate and lead(II) oxide) on setting course of Ordinary Portland cement (OPC). The setting was monitored by Vicat apparatus, the dosage of salts (expressed as wt. % of elementary Pb to OPC) was 0.5, 1, 2 and 5%. Obviously the present anions may also influence the setting time; the set of control experiments with sodium salts of above given anions was performed in order to eliminate the anion effect. The PbO was found to be most detrimental towards retarding of setting, while lead sulfate at higher dosages caused high instability of setting (oscillation). The effect of Pb was, in all cases, more important than influence of given anion.

scholarly journals The Effect of Sodium Gluconate on Pastes’ Performance and Hydration Behavior of Ordinary Portland Cement

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xingdong Lv ◽  
Jiazheng Li ◽  
Chao Lu ◽  
Zhanao Liu ◽  
Yaosheng Tan ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Hydration ◽  
Isothermal Calorimetry ◽  
Setting Time ◽  
Heat Evolution ◽  
Curing Temperature ◽  
Sodium Gluconate ◽  
Early Hydration ◽  
Negative Effect

The goal of this paper provides better understanding of the effect of sodium gluconate (SG) on ordinary Portland cement (OPC) hydration behavior. Pastes’ performances of ordinary Portland cement, including setting time at 20°C and 35°C curing temperature, mechanical strength, fluidity, and zeta potential are studied. Furthermore, the effects of SG on cement hydration behaviors are investigated by the means of isothermal calorimetry measurements, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results show that SG is difficult to maintain significant retarding effect at the temperature of 35°C compared to that at the temperature of 20°C. SG is able to reduce the cement cumulative hydration heat and delay the occurrence time of heat evolution peak in a certain extent, but it has little impact on reducing the cement evolution rate peak. The effects of SG on mechanical properties and dispersion properties of cement depend on its dosages. Specifically, the positive effect occurs when the addition dosage is less than 0.15% (i.e., by cement weight), but the negative effect emerges if the addition dosages exceed this limitation. Similarly, SG plays different roles on cement hydration at different hydration periods. It inhibits the hydration of C3S and the formation of portlandite (CH) at the early hydration period. On the contrary, it promotes the C3S hydration when hydration time is beyond 1 d. Meanwhile, SG also plays different roles on cement hydration at different dosage additions. Specifically, SG promotes ettringite (AFt) formation at the dosage less than 0.06%, but it inhibits AFt formation at the dosage more than 0.06%.

Influence of Clutch Disc Waste (Grinding Dust) on Portland Cement Hydration

2019 ◽  
Vol 803 ◽  
pp. 284-288
Author(s):  
José da Silva Andrade Neto ◽  
Tiago Assunção Santos ◽  
Raphael Dias Mariano ◽  
Marcio Raymundo Morelli ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Propagation Velocity ◽  
Pulse Propagation ◽  
Cement Hydration ◽  
Setting Time ◽  
Reference Sample ◽  
Ultrasonic Pulse ◽  
X Ray Diffraction ◽  
Copper Zinc ◽  
Portland Cement Hydration

This paper evaluates the effect of grinding dust (GD), a waste generated in the clutch disc finishing process, on Portland cement hydration. For this, pastes with additions of 5%, 10% and 15% GD, relative to cement weight, were molded and compared with a reference sample. Tests of setting time determination by Vicat needle, calorimetry, monitoring the ultrasonic pulse propagation velocity and mineralogical analysis (X-ray diffraction) in pastes with 1 day of hydration were carried out. It was observed that GD, due to the presence of copper, zinc and phenolic resin in its composition, is responsible for retarding cement hydration and thus increases the setting time and delays the evolution of heat release and pulse propagation velocity. However, the formation of new crystalline phases was not observed.

Effect of Alkaline Solution to Fly Ash Ratio on Geopolymer Mortar Properties

2017 ◽  
Vol 733 ◽  
pp. 85-88 ◽  
Author(s):  
Amir Fauzi ◽  
Mohd Fadhil Nuruddin ◽  
Ahmad B. Malkawi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Bashar S. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Alkaline Solution ◽  
Similar Pattern ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Pozzolanic Reaction

Geopolymer system is new binding materials in concrete industry that is produced by the alkaline solution and materials rich in aluminosilicate such as fly ash. The effect of the alkaline solution to fly ash ratios of 0.3, 0.4 and 0.5 on mortar geopolymer properties was an issue in this study. The results showed that the higher alkaline solution to fly ash ratio improves the workability and brings a longer setting time, whereas the lower alkaline solution to fly ash ratio gains the significant compressive strength. It was a similar pattern with conventional mortar used ordinary Portland cement, which the compressive strength at 7 days was 85%-90% for 28 days compressive strength, whereas conventional mortar is only 65%-75%. This was due to the higher reactivity in geopolymer system that was faster than the pozzolanic reaction.

A Study of Ordinary Portland Cement Hydration With Wood by Isothermal Calorimetry

Holzforschung ◽  
1999 ◽  
Vol 53 (1) ◽  
pp. 104-108 ◽  
Author(s):  
N. Sauvat ◽  
R. Sell ◽  
E. Mougel ◽  
A. Zoulalian
Keyword(s):  
Portland Cement ◽  
Calcium Chloride ◽  
Activated Charcoal ◽  
Ordinary Portland Cement ◽  
Cement Hydration ◽  
Isothermal Calorimetry ◽  
Cement Composites ◽  
Total Enthalpy ◽  
Portland Cement Hydration ◽  
Wood Cement Composites

Summary As an essential preliminary to understand the hydration of wood-cement composites, the effects of some additives on the delayed setting due to wood of an Ordinary Portland Cement have been investigated by isothermal calorimetry. With the addition of calcium chloride and activated charcoal, an increase of 50% of the total enthalpy is observed in wood-cement composites hydration, because calcium chloride mostly influences aluminate phases and activated charcoal silicate phases.

scholarly journals Investigating the Compressive Strength Properties of Concrete Using Some Common Ghanaian Ordinary Portland Cements

2021 ◽  
Vol 6 (2) ◽  
pp. 154-166
Author(s):  
K. S Akorli ◽  
K Danso ◽  
J Ayarkwa ◽  
A Acheampong
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Strength Properties ◽  
Research Strategy ◽  
Cementitious Material ◽  
Direct Function ◽  
Cross Sectional ◽  
Portland Cements ◽  
Concrete Production

In a general sense, concrete is made of cementitious material, aggregates and water but the mix productivity is one issues that affect the amount of strength concrete developed. The concrete mix productivity is a direct function of the amount and quality of the cementitious material. The commonest cementitious material used for concrete in Ghana like other countries in the world is the Ordinary Portland Cement. The research sort to investigate the compressive strength properties of concrete made from some common Ghanaian Ordinary Portland Cement brands mostly used in the countries construction industries. The research strategy adopted was experimental. The research was a cross –sectional studies and used laboratory tests to get information on all cements. Cement grade 42.5N, 42.5R and 32.5R were used. A total of one – hundred and eight (108) concrete cubes were made from nine different brands of Ordinary Portland Cement with a mix design of 1:2:4. No admixtures were used in the mix. It was established that, Ordinary Portland Cement Brand E of grade 42.5R has the highest compressive strength after 28 days. Some of the cement brand with grade 32.5R developed better strength than that of grade 42.5R. Based on the experiment conducted, it can be concluded that for the C15 (1:2:4) and C20 compressive strength as per IS 456:2000, Ordinary Portland Cement Brand E and G of grade 42.5R and Ordinary Portland Cement Brand H and J of grade of 32.5R satisfactory meets the requirement. It implies that some of the Ghanaians Portland Cement developed a satisfactory compressive strength and meets the minimum strength attainment after 28 days’ which is 15 N/mm2. Based on the result, it is recommended that Ordinary Portland Cement Brand E of grade 42.5R should be used for most concrete production and Ordinary Portland Cement Brand J of grade 32.5R can also be used for concrete work in the absence of E 42.5R.   Citation: Akorli, K. S., Danso, K., Ayarkwa, J. and Acheampong, A. (2021). Investigating the Compressive Strength Properties of Concrete Using Some Common Ghanaian Ordinary Portland Cements. International Journal of Technology and Management Research (IJTMR), Vol. 6 (1): Pp.154-166.[Received: March 13, 2021Accepted: September 1, 2021

scholarly journals Comparison of Effects of Sodium Bicarbonate and Sodium Carbonate on the Hydration and Properties of Portland Cement Paste

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1033 ◽  
Author(s):  
Yuli Wang ◽  
Fengxia He ◽  
Junjie Wang ◽  
Qianku Hu
Keyword(s):  
Compressive Strength ◽  
Sodium Bicarbonate ◽  
Portland Cement ◽  
Cement Paste ◽  
Sodium Carbonate ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Sprayed Concrete ◽  
Final Setting Time ◽  
Portland Cement Paste

Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete. In this study, the effects of the two accelerators sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) (0%, 1%, 2%, 3%, and 4% by weight of ordinary Portland cement OPC) on the properties of OPC paste were compared. The results show that both of them could accelerate the initial and final setting time of OPC paste, but the effect of the two accelerators on the compressive strength were different. After 1 day, sodium bicarbonate at 3% had the highest strength while sodium carbonate at 1% had the highest strength. After 7 days, both of the two accelerators at 1% had the highest compressive strength. After 28 days, the compressive strength decreased with the increase of the two. The improved strength at 1 and 7 days was caused by the accelerated formation of ettringite and the formation of CaCO3 through the reactions between the two with portlandite. The decrease of strength was caused by the Na+ could reduce the adhesion between C-S-H gel by replacing the Ca2+. NaHCO3 was found be a better accelerator than Na2CO3.

Study on Corrosion Resistance Coefficient Assessment Method for Sulfate Resistance of Cementitious Material

2012 ◽  
Vol 174-177 ◽  
pp. 624-630
Author(s):  
Kun Peng Gu ◽  
Cheng Qi Wang
Keyword(s):  
Corrosion Resistance ◽  
Portland Cement ◽  
Resistance Coefficient ◽  
Assessment Method ◽  
Cementitious Material ◽  
Mineral Admixture ◽  
Corrosion Mechanism ◽  
Experimental Conditions ◽  
Sulfate Resistance ◽  
Coefficient Method

By means of testing corrosion resistance coefficient of different cementitious material under the sulfate corrosion experimental conditions, sulfate resistance of cementitious material and assessment method are studied. The results show that 90d is proper corroded age for assessment sulfate resistance of cementitious material by corrosion resistance coefficient method, and the assessment method is put forwarded. Sulfate resistance of cementitious material can be divided into five classes according to corrosion resistance coefficient assessment method as follows: “very low”, “low”, “moderate”, “high” and “very high”. The sulfate resistance of Portland cement is better than ordinary Portland cement, and both of them are low. Mineral admixture with proper content can improve sulfate resistance of cementitious materia largely, but do not always available to all content. Sulfate corrosion mechanism of different kinds of cementitious material is analyzed.

scholarly journals Elucidating the Pozzolanic Characteristics of Pastes Containing Circulating Fluidized Bed Fly Ash

2015 ◽  
Vol 9 (1) ◽  
pp. 180-186
Author(s):  
Kae-Long Lin ◽  
Chao-Lung Hwang ◽  
Yu-Min Chang
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Ordinary Portland Cement ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Blended Cement ◽  
Curing Time ◽  
Cement Pastes ◽  
Space Ratio

The aim of this study is to investigate the pozzolanic characteristics of circulating fluidized bed fly ash blended cement (CFBFABC) paste containing circulating fluidized bed fly ash (CFBFA). The initial and final setting time of CFBFABC pastes with CFBFA retards with an increasing CFBFA content. CFBFABC pastes containing 10% CFBFA exhibited a compressive strength similar to that of ordinary Portland cement pastes at the ages of 90 days. X-ray diffraction peaks indicated the presence of portlandite, ettringite, and unreacted C3S (32.6°) and C2 (41.9°). The gel/space ratio of the CFBFABC pastes increased with the curing time and decreased as the CFBFA content increased. The gel/space ratio increased with the curing time because of the progress of hydration, which led to some of the pores being filled. At the ages of 90 days, the gel/space ratio of the CFBFABC pastes containing 10% CFBFA increased to approximately 14%, it is possibly the consumption of Ca(OH)2 and the formation of C-S-H in the CFBFABC pastes. The CFBFABC pastes containing 10% CFBFA did not exhibit any major decrease in the gel/space ratio. It exhibited favorable mechanical characteristics that were observed when the mixing ratio of CFBFA was 10%. Furthermore, CFBFA has the potential, as a pozzolanic material, partially to replace ordinary Portland cement.

scholarly journals Effect of Aluminium Dross on Workability and Setting Time of Cement and Concrete

2021 ◽  
Vol 9 (VII) ◽  
pp. 1851-1859
Author(s):  
Panditharadhya B J
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Positive Impact ◽  
Setting Time ◽  
Waste Product ◽  
Weather Conditions ◽  
Industrial Wastes ◽  
Raw Material ◽  
Partial Replacement ◽  
Aluminium Dross

Aluminium dross is generated when resmelting process is done in an aluminium industry to recover residual aluminium, wherein primary dross is taken as a raw material. It is completely a waste product and hazardous to dispose it into landfills. This is rich in aluminium oxide and having traces of few heavy metals. It is necessary to check the eco-friendly methods of solidification of this material. One of the feasible methods of solidifying the industrial wastes is using them in production of cement concrete. In this study, behaviour of aluminium dross as a partial replacement for Ordinary Portland Cement is evaluated. Aluminium dross is replaced at 5, 10, 15 and 20% of Ordinary Portland Cement. Consistency and setting time of cement paste samples were determined which shows a lag in setting time of paste. Workability and setting time of concrete mixes with 5, 10, 15 and 20% of Aluminium dross as a binder, were evaluated. Retardation of setting time and increase in the workability are the main observations of this study. As the percentage of aluminium dross increases, the setting time also increases. This may be considered as a reason to utilize such concrete mixes in hot weather conditions wherein delayed setting time is an added advantage. Therefore, retardation of setting time is the positive impact of aluminium dross. Keeping in view of the fact that there can be a reduction in strength with increased binder replacement and the workability requirements, only up to 20% of aluminium dross was replaced in the present study.

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