AMMONIUM SULFATE ATTACK ON CEMENT MORTAR

Author(s):  
F Rendell ◽  
R Jauberthie
2014 ◽  
Vol 576 ◽  
pp. 133-141
Author(s):  
Shou Qi Zhang ◽  
Shu Xiong Zhang ◽  
Yu Fang Fu ◽  
Dong Min Wang

The key factors for activity of asbestos tailings acid leaching residue (ATALR) and activated process were researched by the way of orthoplan, so as to make a new type of high-active mineral admixture in cement-based material, named as porous silica fume (PSF). Then with the strength loss indexes designed, the sulfate attack resistance of cement-PSF mortars was evaluated, which was dunked in solution of sodium sulfate during from 6 to 12 months. The results indicated that thermal activated temperature and holding time was the key factor for compressive strength, while holding time and grinding time for flexural strength. The optimal activated process was the thermal activated temperature at800°C needing to hold for 1 hour before grinding for 20minuteswhilethe appropriate amount of PSF was 5%~12% in cement mortar. When 5%~8% PSF contained, the sulfate attack resistance of cement mortar can be improved obviously, and the role was similar to silica fume (SF). PSF activated from ATALR is helpful for resource utilization of asbestos tailings, in order to improve ecological environment in the asbestos mine town and promote cement-based material development.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Ailian Zhang ◽  
Linchun Zhang

Cement mortar prisms were prepared with three different cement types and different water-to-cement ratios plus 30% mass of limestone filler. After 28 days of curing in water at room temperature, these samples were submerged in 2% magnesium sulfate solution at 5°C and the visual appearance and strength development for every mortar were measured at intervals up to 1 year. Samples selected from the surface of prisms after 1-year immersion were examined by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results show that mortars with sulfate resisting Portland cement (SRC) or sulphoaluminate cement (SAC) underwent weaker degradation due to the thaumasite form of sulfate attack than mortars with ordinary Portland cement (OPC). A lower water-to-cement ratio leads to better resistance to the thaumasite form of sulfate attack of the cement mortar. A great deal of thaumasite or thaumasite-containing materials formed in the OPC mortar, and a trace of thaumasite can also be detected in SRC and SAC mortars. Therefore, the thaumasite form of sulfate attack can be alleviated but cannot be avoided by the use of SAC or SRC.


2008 ◽  
Vol 20 (4) ◽  
pp. 139-144 ◽  
Author(s):  
A. Guerrero ◽  
S. Goñi ◽  
M. P. Lorenzo

2021 ◽  
Vol 11 (5) ◽  
pp. 2226
Author(s):  
Gun-Cheol Lee ◽  
Youngmin Kim ◽  
Soo-Yeon Seo ◽  
Hyun-Do Yun ◽  
Seongwon Hong

This study analyzed changes in the durability characteristics of cement mortar incorporating carbon nanotube (CNT) and the electrical properties subjected to deterioration induced by sulfate attack. Powder types of multi-walled or single-walled CNTs were used and added to the composites with 1.0% and 2.0% mass fraction, and the specimens were immersed in 5% and 10% sulfuric acid solutions to investigate the durability of CNT cementitious composites. Although mechanical performance decreased due to relatively large pores (370–80 μm) caused by CNTs, specimens incorporating CNTs exhibited enhanced resistance to sulfuric acid as CNTs, which offered strong resistance to acid corrosion, and prevented contact between the cement hydrate and the sulfuric acid solution. Therefore, it is expected that self-sensing performance was exhibited because there were no significant differences in the electrical properties of cement mortar subjected to the deterioration by sulfate attack.


2018 ◽  
Vol 189 ◽  
pp. 686-694 ◽  
Author(s):  
Warun Wongprachum ◽  
Manote Sappakittipakorn ◽  
Piti Sukontasukkul ◽  
Prinya Chindaprasirt ◽  
Nemkumar Banthia

2012 ◽  
Vol 174-177 ◽  
pp. 121-126
Author(s):  
Feng Chen Zhang ◽  
Yong Hao Fang ◽  
De Jian Shen ◽  
Ji Kai Zhou

It is very difficult to evaluate risk of sulfate attack and diagnose the form of sulfate attack of cement mortar and concrete because of the diversity of attack form and complexity of erosion phases during sulfate attack, which affect repair of concrete component damaged by sulfate attack mostly. From the sulfate ions, ambient temperature and humidity of service environment as well as local climate characteristics, key components of building structures suffered great risk of sulfate attack should be inspected well and master the property of cement-based material, and then evaluate the risk of sulfate attack. In this foundation, three main erosion phases which are ettringite, gypsum and thaumasite are distinguished by micro-analysis and so the form of sulfate attack can be identified.


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