scholarly journals Influence of Magnesium Sulfate on Self-Compacting Alum Sludge Concrete Incorporating with Pozzolanic Materials

2016 ◽  
Vol 10 (8) ◽  
pp. 187
Author(s):  
Khalid M. Breesem ◽  
Manal M. Abood ◽  
Nurharniza Abdul Rahman
Keyword(s):  
Magnesium Sulfate ◽  
Natural Zeolite ◽  
Visual Inspection ◽  
Sulfate Attack ◽  
Sulphate Attack ◽  
New Materials ◽  
Self Compacting Concrete ◽  
Concrete Technology ◽  
Maximum Value ◽  
Alum Sludge

Self-compacting concrete (SCC) is a new revolution in concrete technology that made with no vibration equipment in placing and compaction. Totally, filling formwork and accomplishing full compacting under its own weight only, even when is attendance of crowded reinforcement. One of the issues that impact SCC durability is sulphate attack. The influence of magnesium sulfate attack was investigated for SCC having treated alum sludge (TAS) with ordinary Portland cement (OPC) at replacement ratios of 5%, 10%, 15% and 20% as well as, six SCC containing TAS, fly ash (FA), silica fume (SF) and natural zeolite (NZ) replaced cement by15%, 15%, 6% and 10%, respectively. By visual inspection of all samples of SCC, there was no indication of deterioration on the surface of samples after 90 days and 180 days. In terms of compressive strength, there was developed with samples substituted OPC by 15% TAS compared with control SCC and the others SCC replacement levels. A similar conclusion was observed of the characteristics of SCC on weight compared with control SCC. Results proved that the SCC contain TAS have higher resistance against sulfate attack as well as the maximum value of mass loss and variation in weight are noted for the control SCC compared with SCC content TAS. Finally, in spite of the system of blended in SCC was investigated in several studies and so far, more investigations are required to fully explore its behavior, especially with new materials which is alum sludge that refer to the pioneering aspect of the present.

scholarly journals Behavior of limestone filler cement mortars exposed to magnesium sulfate attack

2014 ◽  
Vol 11 ◽  
pp. 01043
Author(s):  
Y. Senhadji ◽  
M. Mouli ◽  
G. Escadeillas ◽  
A. Khelafi ◽  
A. S. Bennosman ◽  
...  
Keyword(s):  
Magnesium Sulfate ◽  
Sulfate Attack ◽  
Limestone Filler ◽  
Cement Mortars

scholarly journals Effect of fibre type and content on performance of bio-based concrete containing heat-treated apricot shell

2020 ◽  
Vol 53 (6) ◽  
Author(s):  
Fan Wu ◽  
Qingliang Yu ◽  
Changwu Liu ◽  
H. J. H. Brouwers ◽  
Linfeng Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Magnesium Sulfate ◽  
Fibre Type ◽  
Lightweight Concrete ◽  
Sulfate Attack ◽  
Fibre Glass ◽  
Heat Treated ◽  
Apricot Shell

AbstractThe heat-treated apricot shell can be utilized as coarse aggregates for producing sustainable bio-based lightweight concrete with good compressive strength but poor tensile strength. In order to improve the tensile properties of apricot shell concrete (ASC), the effects of polypropylene (PP) fibre, glass (G) fibre and basalt (B) fibre at various volume fractions (Vf) (0.25%, 0.5% and 0.75%) on the performance of ASC were investigated. The results indicated that the fibre type had no significant effect on the physical properties of ASC such as slump, density, water absorption and permeable porosity. However, the slump of ASC decreases with an increase in fibre content. The B fibre has a better improvement in mechanical properties than the PP fibre and G fibre thanks to the better elastic modulus and tensile strength. When the Vf was 0.5%, the compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of ASC reinforced with B fibre were increased by 16.7%, 29.1%, 29.2%, and 18.1%, respectively, compared to ASC without any fibres. The magnesium sulfate attack results showed that the incorporation of the B fibre decreased the mass loss and compressive strength of ASC exposed to a MgSO4 solution for 6 months because the fibre arrested the microcracks caused by the expansive stress. It is concluded that the mechanical properties of bio-based ASC and its resistance to magnesium sulfate attack can be significantly improved by incorporating 0.5% B fibre.

scholarly journals Deterioration and Microstructural Evolution of the Fly Ash Geopolymer Concrete against MgSO4Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Tao Long ◽  
Qingyuan Wang ◽  
Zhongwei Guan ◽  
Yu Chen ◽  
Xiaoshuang Shi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Magnesium Sulfate ◽  
Strength Loss ◽  
Sulfate Attack ◽  
Aluminum Silicate ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Sodium Aluminum Silicate ◽  
Magnesium Aluminum Silicate

Fly ash geopolymer concrete (FAGC) and ordinary Portland cement concrete (OPCC) specimens were immersed in 5% MgSO4solution undergoing 32 wetting-drying and heating-cooling cycles. Their compressive behavior was investigated after every 8 cycles. Several microstructure analysis techniques were applied on the samples to identify the materials formed due to magnesium sulfate attack, including XRD, FTIR, SEM, and EDS. Experimental results elucidated that the compressive strength loss ratio in the heating group of FAGC was 12.7%, while that of OPCC was 17.8%, which means that FAGC had better magnesium sulfate resistance than OPCC. The compressive strength loss of OPCC was due to the formation of gypsum under the magnesium sulfate attack exposed to wetting-drying and heating-cooling cycles. The deterioration mechanisms of FAGC against MgSO4solution were discovered to be that sodium aluminum silicate hydrate (N-A-S-H) gels reacted with MgSO4, leading to the creation of low strength magnesium aluminum silicate hydrate (M-A-S-H) gels.

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.

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