Deterioration of Cement Pastes Containing Limestone Powder with Different Fineness Exposed to Sulfate Environment at Low Temperature

2013 ◽  
Vol 423-426 ◽  
pp. 1076-1080
Author(s):  
Feng Chen Zhang ◽  
Ruo Yu Tang ◽  
Yun Zhao
Keyword(s):  
Fourier Transform ◽  
Low Temperature ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
Test Results ◽  
X Ray Diffraction ◽  
Limestone Filler ◽  
Cement Pastes ◽  
Cement Production ◽  
X Ray

Limestone filler and aggregates are used widely in cement production and concrete mixing nowadays, which could be connected with thaumasite formation, and lead to a lack of durability further in sulfate environment. This work deals with the deterioration of cement pastes containing 35% w/w limestone powder with different fineness immersed in MgSO4 solution at 5°C±2°C for 15 weeks by. Erosion phases are discussed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). Test results show that visual deterioration of three kinds of cement pastes containing 400-mesh, 800-mesh and 1250-mesh limestone powders has little distinction, and erosion phases are all compound of ettringite, thaumasite, gypsum and brucite. Limestone powders with fineness of 400-mesh could supply enough carbonate needed for thaumastie formation. Increase of limestone fineness further could not accelerate deterioration of cement paste during the external magnesium sulfate attack at low temperature.

Erosion Phases in Two Types of Cement Pastes Containing Limestone Exposed to Sulfate Attack

2014 ◽  
Vol 584-586 ◽  
pp. 1182-1187 ◽  
Author(s):  
Feng Chen Zhang ◽  
Yun Zhao ◽  
Fu Wan Zhu
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Limestone Powder ◽  
Test Results ◽  
X Ray Diffraction ◽  
Limestone Filler ◽  
Cement Pastes ◽  
Cement Production ◽  
X Ray ◽  
Gypsum Formation

Limestone filler and aggregates are used widely in cement production and concrete mixing nowadays, which could be connected with thaumasite formation, and lead to a lack of durability further. This work deals with the sulfate minerals including of thaumasite, ettringite and gypsum in two types of cement pastes containing 35% w/w limestone powder immersed in MgSO4 solution at 5°C±2°C for 15 weeks by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). Two types of cements were used: (i) ordinary Portland cement (P·O), (ii) typeII Portland cement (P·II). Test results show that thaumasite is present in two types of cement pastes, amount of thaumasite as well as amount of portlandite reacted with external SO42- in P·II cement paste are more than those in P·O cement paste. It indicates that P·II cement is more susceptible to thaumasite formation than P·O cement containing the same amount of limestone powder, and more gypsum formation could contribute to thaumasite formation possibly during the external MgSO4 attack at low temperature.

Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

2021 ◽  
Vol 11 (5) ◽  
pp. 724-731
Author(s):  
Hemin Liu ◽  
Qian Huang ◽  
Liang Zhao
Keyword(s):  
Ambient Temperature ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Adverse Influence ◽  
Powder Content ◽  
Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

Accelerate Thaumasite Formation in Cement-Limestone Powder Paste by Internal Adding Method

2011 ◽  
Vol 250-253 ◽  
pp. 22-27 ◽  
Author(s):  
Chang Cheng Li ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Magnesium Sulfate ◽  
Sodium Sulfate ◽  
Calcium Sulfate ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cement Based Materials ◽  
Internal Sulfate Attack

Cement-limestone powder pastes added with 10% magnesium sulfate, sodium sulfate, and calcium sulfate respectively were stored in water at (5±2) °C to accelerate thaumasite formation. The pastes were inspected visually at intervals. And the formation of thaumasite was identified and confirmed by X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The results show that internal adding sulfate in cement-limestone powder paste is an efficient way to accelerate thaumasite formation, and the accelerated effect is magnesium sulfate> sodium sulfate> calcium sulfate. Cement-limestone paste containing 10% magnesium sulfate totally turns into grey-white mushy materials after 6 months immersion, and products are mainly thaumasite and gypsum. In addition, the amount of thaumasite increases along with time of internal sulfate attack in 15 months. XRD, IR, and NMR are powerful and reliable tools for identification of thaumasite in cement-based materials.

scholarly journals Effect of Limestone Powder on Thaumasite Form of Sulfate Attack (TSA) of Cement-Based Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yuxin Gao ◽  
Yaoling Luo ◽  
Lili Jia ◽  
Wen Yang ◽  
Chong Wang
Keyword(s):  
New Product ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
Test Results ◽  
X Ray Diffraction ◽  
Cement Based Materials ◽  
Powder Content ◽  
Degradation Degree ◽  
The Relationship ◽  
Hydrated Calcium

Limestone powder can cause the thaumasite form of sulfate attack (TSA) of cement-based materials, but the relationship between the content of limestone powder and the degree of TSA is unclear. Hence, six different contents of limestone powder (0%, 5%, 10%, 15%, 30%, and 45%) were used to study the effect of the limestone powder content on the TSA of cement-based materials according to appearance and Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and chemical analyses. The test results indicated that limestone powder could promote sulfate attack. The formation of ettringite and gypsum was accelerated when the content of the limestone powder was not more than 10%. The degradation degree of the TSA was the most severe when the content of limestone powder was 30%. A new product, hydrated calcium carboaluminate, was found when the content of the limestone powder was 45%, and the degradation of the TSA was also delayed.

scholarly journals Evaluation of external sulfate attack (Na2SO4 and MgSO4): Portland cement mortars containing fillers

2020 ◽  
Vol 13 (3) ◽  
pp. 644-655 ◽  
Author(s):  
D. J. DE SOUZA ◽  
M. H. F. MEDEIROS ◽  
J. HOPPE FILHO
Keyword(s):  
Portland Cement ◽  
Linear Expansion ◽  
Sulfate Attack ◽  
Hardened Cement ◽  
X Ray Diffraction ◽  
Limestone Filler ◽  
Sulfate Ions ◽  
X Ray ◽  
Cement Mortars ◽  
Physical And Chemical

Abstract Sulfate attack is a term used to describe a series of chemical reactions between sulfate ions and hydrated compounds of the hardened cement paste. The present study aims to evaluate the physical (linear expansion, flexural and compressive strength) and mineralogical properties (X-ray diffraction) of three different mortar compositions (Portland Cement CPV-ARI with limestone filler and, with a quartz filler, in both cases with 10% replacement of the cement by weight) against sodium and magnesium sulfate attack (concentration of SO4 2- equal to 0.7 molar). The data collected indicate that the replacing the cement by the two fillers generate different results, the quartz filler presented a mitigating behaviour towards the sulfate, and the limestone filler was harmful to Portland cement mortars, in both physical and chemical characteristics.

Comparison of FT-IR, Thermal Analysis and XRD for Determination of Products of Cement Hydration

2010 ◽  
Vol 168-170 ◽  
pp. 518-522 ◽  
Author(s):  
Zhi Hua Ou ◽  
Bao Guo Ma ◽  
Shou Wei Jian
Keyword(s):  
Thermal Analysis ◽  
Fourier Transform ◽  
Cement Hydration ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Degree Of Hydration ◽  
Ft Ir

Fourier Transform Infrared Spectroscopy (FT-IR), thermal analysis and X-Ray Diffraction (XRD) are commonly performed to study the hydration products in cement pastes. The three methods were compared in this frame to detect products of cement hydration at different ages, especially at early ages (before 24h ages). The results indicate from the present experiment that CH (Calcium hydroxide) can be detected by three methods at all ages; C-S-H can be distinguished by FT-IR at all ages; ettringite may be detected by FT-IR before 24h ages and by XRD at all ages; and monosulphate can be detected by FT-IR before 24h ages. The process of cement hydration, characterized by formation and development of some hydration products, can be clearly observed by three methods. FT-IR is suggested for detecting the major hydration products before 24h ages, FT-IR and XRD are suggested for detecting the major hydration products after 24h ages, and thermal analysis is suggested for analyzing the degree of hydration quantitatively.

Rapid Quantitative Identification of Thaumasite

2013 ◽  
Vol 743-744 ◽  
pp. 186-192 ◽  
Author(s):  
Chang Cheng Li ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Magnesium Sulfate ◽  
Rietveld Refinement ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Identification Method ◽  
Quantitative Identification ◽  
Ir Analysis

To establish a quantitative identification method of thaumasite, internal doping method was used to accelerate thaumasite form of sulfate attack (TSA). A cement-limestone powder paste doped 10% of magnesium sulfate was immersed in water at (5±2) °C, while the blank was in 10% magnesium sulfate solution (by weight). Paste corrosion products were analyzed by infrared spectrum (IR), thermal analysis, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD)/Rietveld refinement methods. The results show that the thaumasite formation was successfully accelerated by internal doping method. A lot of thaumasite formed after 6-15 months low temperature sulfate attack with gray mud-like material. IR analysis is able to be used to analysis thaumasite qualitatively, and Rietveld refinement was suitable to quantitative analysis of thaumasite. A rapid quantitative identification method of thaumasite including visual inspection, IR spectrum and XRD/Rietveld refinement was also established which will improve the accuracy and rapidness of TSAs research.

Study on the Change in Microstructure of Fly Ash Concrete Depending on Ages and Degree of Hydration Using XRD and SEM

2012 ◽  
Vol 486 ◽  
pp. 350-355 ◽  
Author(s):  
Ho Jae Lee ◽  
Jang Hwa Lee ◽  
Do Gyeum Kim
Keyword(s):  
Fly Ash ◽  
Blended Cement ◽  
Type I ◽  
Test Results ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Degree Of Hydration ◽  
Fly Ash Concrete ◽  
Blended Cement Paste

This research analyzes the microstructure of hardened blended cement pastes. Fly ash was used to replace Portland cement type I paste. Test results indicated that hardened blended cement paste were significantly affected by duration after mixing. The X-ray diffraction (XRD) and the scanning electron microscope (SEM) showed changes of microstructure by duration.

Effect of Initial Curing Conditions on Thaumasite Form of Sulfate Attack of Cement Based Materials

2013 ◽  
Vol 275-277 ◽  
pp. 2136-2140 ◽  
Author(s):  
Chang Hui Yang ◽  
Xiao Bin Xiang ◽  
Ben Wan Liu ◽  
Jing Zhang
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Sulfate Attack ◽  
X Ray Diffraction ◽  
Hydration Degree ◽  
Humid Air ◽  
Curing Conditions ◽  
X Ray ◽  
Cement Based Materials ◽  
Water Curing

The effects of initial high humid air-curing, standard water-curing and sealed-curing on thaumasite form of sulfate attack (TSA) of cement based materials were studied. The erosion products after three years attack in 5% MgSO4 solution were analyzed by means of X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Initial high humid air-curing can delay the TSA of specimens for CaCO3 generated by carbonation and filled in the pores of the specimens, forming a compacted surface and restricting the intrusion of SO42-. In comparison, specimens cured in sealed condition occurred TSA most serious resulting from that large amount of inter-defects in specimens for the lower hydration degree, and SO42- ions could intrude into specimens more easily.

The Influence of Limestone Powder on Fluidity, Strength and Hydration of Cement Mortar

2010 ◽  
Vol 168-170 ◽  
pp. 512-517 ◽  
Author(s):  
Hua Shan Yang ◽  
Kun He Fang ◽  
Sheng Jin Tu
Keyword(s):  
Cement Mortar ◽  
Xrd Analysis ◽  
Water Requirement ◽  
Limestone Powder ◽  
Experimental Program ◽  
Test Results ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Relationship

An experimental program has been conducted to investigate the influence of limestone powder (LP) on fluidity, strength, and hydration of cement mortar. Four laboratory grinds were prepared using a ball mill. The relationship between roundness of the LP and water requirement of paste, fluidity and strength of mortar was studied. The influence of LP on hydration of cement was investigated. Hydration products were determined by X-ray diffraction (XRD) analysis. Test results show that the roundness of LP significantly affected the water requirement of paste, fluidity and strength of mortar. In addition, the sites for the nucleation and growth of hydration products, provided by LP, accelerate the hydration of cement at early ages. While the enhancement of cement hydration at later ages mainly due to the formation of calcium aluminate monocarbonate.

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