Experimental Study on Accelerated Speed of Concrete Sulfate Attack

2012 ◽  
Vol 204-208 ◽  
pp. 3754-3759
Author(s):  
Hong Fei Liu ◽  
Fa Jun Huang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Insignificant Difference ◽  
Compressive Strength Of Concrete

Through test on compressive strength of concrete and mass changes, the effects of solution concentration and temperature on speed of concrete sulfate attack were investigated. The results show that, the speed of attack is accelerated with increasing concentration and temperature, as well as the decreasing of the size of the specimen, sulfate attack speed at 45 °C sodium sulfate solution soak with wet and dry cycle is insignificant difference with at 20 °C.It is suitable to adopt compressive strength as the assessing criterion of the sodium sulfate attack.

X-Ray Microtomography of an Astm C109 Mortar Exposed to Sulfate Attack

1994 ◽  
Vol 370 ◽  
Author(s):  
D.P. Bentz ◽  
Nicos. S. Martys ◽  
P. Stutzman ◽  
M. S. Levenson ◽  
E.J. Garboczi ◽  
...  
Keyword(s):  
Cement Paste ◽  
Sodium Sulfate ◽  
Three Dimensional ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Mortar Sample ◽  
Air Voids ◽  
X Ray ◽  
Dimensional Image

AbstractX-ray microtomography can be used to generate three-dimensional 5123 images of random materials at a resolution of a few micrometers per voxel. This technique has been used to obtain an image of an ASTM C109 mortar sample that had been exposed to a sodium sulfate solution. The three-dimensional image clearly shows sand grains, cement paste, air voids, cracks, and needle-like crystals growing in the air voids. Volume fractions of sand and cement paste determined from the image agree well with the known quantities. Implications for the study of microstructure and proposed uses of X-ray microtomography on cement-based composites are discussed.

scholarly journals Study on the Deterioration of Concrete under Dry–Wet Cycle and Sulfate Attack

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4095
Author(s):  
Fang Liu ◽  
Tonghuan Zhang ◽  
Tao Luo ◽  
Mengzhen Zhou ◽  
Kunkun Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sodium Sulfate ◽  
Distribution Curve ◽  
Early Stage ◽  
Sulfate Attack ◽  
Industrial Computed Tomography ◽  
Spectrum Distribution ◽  
Compressive Strength Of Concrete ◽  
Internal Pore Structure ◽  
Internal Pore

In order to study the deterioration and mechanism of dry–wet cycles and sulfate attack on the performance of concrete in seaside and saline areas, the deterioration of compressive strength of concrete with different water cement ratios under different erosion environments (sodium sulfate soaking at room temperature and coupling of dry–wet cycling and sodium sulfate) was studied here. At the same time, ICT (industrial computed tomography) and NMR (nuclear magnetic resonance) techniques were used to analyze the internal pore structure of concrete under different erosion environments. The results show that the compressive strength under different erosion environments increases first and then decreases, and the dry–wet cycle accelerates the sulfate erosion. With the increase of dry and wet cycles, larger pores are filled with erosion products and developed into small pores in the early stage of erosion; in the later stage of erosion, the proportion of larger pores increases, and cracks occur inside the sample. In the process of sulfate soaking and erosion, the smaller pores in the concrete account for the majority. As the sulfate erosion continues, the T2 spectrum distribution curve gradually moves right, and the signal intensity of the larger pores increases.

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

2020 ◽  
Vol 70 (337) ◽  
pp. 212
Author(s):  
L. R. Santillán ◽  
F. Locati ◽  
Y. A. Villagrán-Zaccardi ◽  
C. J. Zega
Keyword(s):  
Sodium Sulfate ◽  
Fluorescent Microscopy ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Sodium Sulfate Solution ◽  
Microscopy Image

The effect of recycled concrete aggregate (RCA) on concrete performance against external sulfate attack (ESA) is not yet fully known. In this paper, recycled aggregate concretes (RAC) with 0, 50, 75 and 100% of RCA contents were evaluated after 10 years of exposure immersed in 50g/l sodium sulfate solution. Sulfate ingress profiles were obtained by wet chemical analyses and FRX. Also, the mineralogy of the ingress profile was evaluated by thermogravimetric analyses. Finally, microcracking development in samples was evaluated by optical fluorescent microscopy image analysis. Although RAC showed a slight increase in sulfate ingress, due to its higher porosity (about 30% higher SO3 content near the surface for 50% or higher replacement ratio than control concrete), a dense new matrix still allows a good performance of RAC to external sulfate attack with even 100% RCA content.

Application of Non-Destructive Technology in Evaluating Concrete to Sulfate Attack

2010 ◽  
Vol 168-170 ◽  
pp. 2565-2570 ◽  
Author(s):  
Xu Guang Tang ◽  
You Jun Xie ◽  
Guang Cheng Long
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Chemical Erosion ◽  
Dynamic Modulus Of Elasticity ◽  
Non Destructive

The deterioration on sulfate attack was investigated both in physical crystallization and the chemical erosion. Specimens that suffered long-term immersion and dry-wet cycles in saturated sodium sulfate solution are compared to trace the physical attack. And the chemical erosion was conducted by comparing specimens which have been suffered long-term immersion in saturated sodium sulfate solution and saturated limestone solution. In the investigation, the non-destructive detecting indexes, such as the ultrasonic velocity, and the dynamic modulus of elasticity were measured. The permeability, the porosity and mechanical strength at 28-day age were measured. The flexural/compressive strength was measured after 90 wet-dry cycles. And then all the specimens were cut into cubes to take the measure of compressive strength. Based on the experiments, feasibility of various parameters, such permeability, relative dynamic modulus of elasticity, ultrasonic velocity and relative flexural/compressive strength, were investigated to evaluate the concrete deterioration. The results indicate that there is a close relationship between the deterioration by sulfate attack and concrete permeability, so the reduction of permeability is effective in promoting the resistance. The index of the resistance expressed by the dynamic modulus of elasticity ratio is comparable to that expressed by the relative flexural strength. A novel method was suggested in evaluating concrete by sulfate attack, namely, combined with some mechanical tests, the parameter of relative dynamic modulus of elasticity can be used to evaluate the deterioration; the permeability denoted as the amount of transporting charges within 6 hours can be used to evaluate the properties to sulfate attack.

scholarly journals Damage and Degradation of Concrete under Coupling Action of Freeze-Thaw Cycle and Sulfate Attack

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Wei Tian ◽  
Fangfang Gao
Keyword(s):  
Fly Ash ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Failure Characteristics ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Two Stages

In this study, the mechanical behaviors, failure characteristics, and microstructure of concrete containing fly ash (FA) against combined freeze-thaw cycles and sulfate attack were studied compared with normal concrete, and the formation rates of corrosion products during coupling cycles were investigated. Results showed that, during the coupling action of freeze-thaw cycles and sodium sulfate solution, concrete containing 10% fly ash exposed in 5% sodium sulfate solution exhibited better freeze-thaw resistance. Meanwhile, the variation of compressive strength of concrete during the coupling cycles could be divided into two stages, including the strength enhancement stage and the strength reduction stage. Moreover, the proportion of micropores and capillary pores decreased obviously during combined freeze-thaw cycles and sulfate attack, and excessive concentration of sodium sulfate solution led to more macropores after high-frequency freeze-thaw cycles.

Effect of Fly Ash on Resistance to Sulfate Attack of Cement-Based Materials

2013 ◽  
Vol 539 ◽  
pp. 124-129 ◽  
Author(s):  
Kai Wei Liu ◽  
Min Deng ◽  
Li Wu Mo
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Length Change ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Reaction Products ◽  
Visual Appearance ◽  
Cement Based Materials

The resistance to sulfate attack of mortars containing 0%, 20%, and 40% of fly ash cured in 5 wt. % sodium sulfate solution at 20°C was investigated in this paper. Visual appearance, cracking analysis, velocity of ultrasonic wave and length change were applied to evaluate the sulfate resistance of mortars. The phases and microstructure of the reaction products due to sulfate attack were examined by XRD and SEM, and the pore structure of the mortars was analyzed by MIP. The effects of fly ash on the sulfate attack of mortars were analyzed. Results indicated that the addition of fly ash improved the resistance of sulfate attack significantly, this probably contributed to the pozzonlanic reaction of fly ash.

scholarly journals Tests on the Mechanical Properties of Corroded Cement Mortar after High Temperature

2020 ◽  
Vol 6 (3) ◽  
pp. 459-469 ◽  
Author(s):  
Xiong Liang-Xiao ◽  
Chen Cong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Sodium Sulfate ◽  
Sea Water ◽  
Cement Mortar ◽  
Peak Stress ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution ◽  
Compression Tests

Durability of cement mortar and concrete materials under sea water condition is always an important research topic. The objective of this work is to understand the mechanical properties of corroded cement mortar after high temperature, the cement mortar specimens after high temperature were placed in water and sodium sulfate solution, and then the uniaxial compression tests were carried out on the cement mortar specimens after corroded. Test results show that both the differences of compressive strength and strain at the peak stress after high temperature caused by high temperature, are relatively small when the specimens are eroded in water, and the differences are relatively high when the specimens are eroded in sodium sulfate solution. The compressive strength of the cement mortar specimens under normal temperature eroded in sodium sulfate solution is highest, and that eroded in water is lowest. The compressive strength of specimen after high temperature eroded in water is highest and that eroded in sodium sulfate solution is lowest. The strain at the peak stress of specimen, whether after high temperature or not, is highest when eroded in sodium sulfate solution, and that eroded in water is lowest. At present, there are few research results about the mechanical properties of concrete first after high temperature and then after sea water corrosion. The work in this paper can enrich the results in this area.

Experimental Study on Long-Term Exposure of Concrete in Magnesium Sulfate Solution

2012 ◽  
Vol 238 ◽  
pp. 129-132
Author(s):  
Feng Lan Li ◽  
Xin Xin Ding ◽  
Li Hui Jin
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Magnesium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Sulfate Ion ◽  
Different Depths ◽  
Magnesium Sulfate Solution

Tests were carried out to study the concrete attacked by magnesium sulfate solution. The concrete specimens were exposed in the magnesium sulfate solution with three different concentrations for 360 days. At the exposure times of 90 days, 180 days, 270 days and 360 days, the properties of concrete such as the mass change, the compressive strength and the tensile strength were measured, and the contents of sulfate-ion diffusing into different depths of concrete were determined. Their changes with the solution concentration and the exposure time are analyzed in this paper, which could be used as reference for the protecting of concrete against the attack of magnesium sulfate.

scholarly journals Mechanical behavior and durability of mortars with quartzite and Portland cement after sulfate attack

2019 ◽  
Vol 24 (4) ◽  
Author(s):  
Sâmea Valensca Alves Barros ◽  
Gelmires de Araújo Neves ◽  
Romualdo Rodrigues Menezes ◽  
Gerbeson Carlos Batista Dantas ◽  
Patrícia Mendonça Pimentel
Keyword(s):  
Mechanical Behavior ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Differential Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Variation ◽  
Complementary Techniques

ABSTRACT The residues of ornamental rocks, especially quartzite, cause great environmental impact. More impulse has been given to research on the recycling of these residues over the last years, particularly for use as aggregates in concrete and mortar. Nevertheless, the studies conducted so far do not mention the behavior of the mortar blended with aggregates coming from residues of ornamental rocks when under chemical attacks in sulfate-rich environment. Thus, in the present study it was sought to add quartzite residues to the mortar, verifying its mechanical behavior and its durability when attacked by sodium sulfate (Na2SO4). The durability of the mortar blended with quartzite residues under sulfate attack was evaluated by the dimensional variation of the test specimens when immersed in sodium sulfate solution, according to the methodology of the NBR 13583 standard. Were used the following complementary techniques: simple compressive strength, X-ray diffraction and thermogravimetric and differential analysis. From the tests, it was verified that the mortars, after attack of sodium sulfate, presented dimensional expansions superior to 0.06%, as well as increased mechanical strength. Therefore, although it was found that the specimens incorporated with quartzite residues were attacked by sulfate, it was observed that it was not able to form sufficient secondary ettringite to mechanically damage the specimens submitted to the sodium sulfate attack.

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