scholarly journals Effect of Mineral Admixtures on the Sulfate Resistance of High-Strength Piles Mortar

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3500
Author(s):  
Yanyan Hu ◽  
Linlin Ma ◽  
Tingshu He

Pre-stressed high-strength concrete piles (PHCP) are widely used in the building industry in China. The main aim of our research was to investigate the utilization of quartz powder, fly ash, and blast furnace slag as mineral additives to prepare PHCP mortar. The samples were prepared using steam and autoclaving steaming. The influence of minerals on the sulfate resistance of mortar was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. The results showed that when compared to single doped quartz powder samples, samples prepared using fly ash or blast furnace slag improved the sulfate resistance of the PHCP mortar. Furthermore, the resistance to sulfate attack of samples with dual doped quartz powder, fly ash, and blast furnace slag also improved. MIP tests showed that mineral additives can change the pore size distribution after autoclave curing. However, the number of aching holes increased after mixing with 20% quartz powder and caused a decrease in the sulfate resistance.

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 596
Author(s):  
Yasuhiro Dosho

To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete.


2014 ◽  
Vol 629-630 ◽  
pp. 371-375
Author(s):  
Ji Wei Cai ◽  
Si Jia Yan ◽  
Gong Lei Wei ◽  
Lu Wang ◽  
Jin Jin Zhou

Fly ash (FA) and granular blast-furnace slag (GBFS) are usual mineral admixtures to conventional concrete, and their contents substituted for Portland cement definitely affect development rate of strength of concrete. C30 and C60 concrete samples with FA and/or GBFS were prepared to study the influence of substitution content of the mineral admixtures on 3 d, 7 d and 28 d strength. The results reveal that the development rate of strength in period from 3 d to 7 d gets slow with increasing content of mineral admixtures except for concrete with only GBFS less than 20%. In the case of substituting FA as the only mineral admixture for part of cement, the development rate of strength of C30 concrete in period from 7 d to 28 d keeps roughly constant even that of C60 concrete increases. When substituting mineral admixtures in the presence of GBFS for cement within experimental range, the development rate of strength in period from 7 d to 28 d gets fast with increasing substitution content. The enhancing effect of combining FA and GBFS occurs in period from 7 d to 28 d for both C30 and C60 concretes (FA+GBFS≤40%), even occurs in period from 3 d to 7 d for C60 concrete. Based on 7 d strength and the development rate, 28 d strength of concrete can be predicted accurately.


2011 ◽  
Vol 99-100 ◽  
pp. 420-425 ◽  
Author(s):  
Qian Rong Yang ◽  
Xiao Qian Wang ◽  
Hui Ji

The strength, expansion and amount of scaling of concrete with compound mineral admixture (CMA) from steel slag, granulated blast furnace slag and fly ash were studied. The result shows that damage by crystallization press from sulfate attack when concrete was exposed to sulfate environments under wetting–drying alternation is much larger than that from sulfate chemical attack. Adding CMA to concrete could reduce the damage from expansion of concrete caused by sulfate chemical attack, but the resistance of concrete to damage by crystallization press from sulfate attack was remarkably reduced.


2011 ◽  
Vol 366 ◽  
pp. 518-521
Author(s):  
Zhi Min He ◽  
Jun Zhe Liu

By use of ASTM C1202, this paper studied the influence of mineral admixtures on the chloride ions penetration resistance of the new-old concrete compound system. The results indicate that the performance of new-old concrete exert significant influence on the new-old concrete compound system. The addition of mineral admixtures improve the permeability properties of new-old concrete. Adding fly ash(FA) require a relatively longer time to get its beneficial effect. When 30% weight of cement is replaced by 10% FA and 20% ground blast furnace slag(GGBFS), the inclusion of 30% mineral admixtures significantly improve the chloride ions penetration resistance properties of the new-old concrete compound system at 28 days and 180 days.


Author(s):  
Jan Pieter Vermeulen ◽  
Natalie Lloyd

This research examines an alternative binder, Alkali Activated Cement (AAC), examining the fresh and hardened mechanical properties of twelve AAC mortar mixes with varying mixture proportions of blast-furnace slag, fly ash, sodium silicate (the alkali activator), and additional water. In addition to the Slag-Fly Ash mortars, nine mixtures with blast-furnace slag, silica fume, aluminum hydrate, sodium silicate, and water were tested. For all mortars, the compressive strength was exponentially related to the water/activator-solids ratio. Mortar strengths at 28 days ranged from 5 MPa to 20 MPa. Increasing the slag to binder-solids ratio from 0.1 to 0.2 increased the strength with water to binder ratios from 0.2 to 0.4. However, rapid or almost instantaneous setting times were observed for a slag to binder-solids ratio of 0.2. The research concluded that using a carefully chosen mix design can prevent quick setting while still achieving high strength and acceptable workability. It is suggested the CaO to binder-solids ratio remain below 0.07; a sodium silicate to binder solids ratio of around 0.25 is optimal; a water to binder-solids ratio should be around 0.3. When replacing fly ash, a Si/Al ratio above 2 is recommended. This research concluded that other solids (Silica Fume and Aluminum Hydrate) could replace Slag and/or Fly Ash if the overall chemical balance of the system is maintained.


2011 ◽  
Vol 99-100 ◽  
pp. 758-761
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du

In this study, concrete prisms were made with three mineral admixtures: fly ash, blast furnace slag or silica fume and with three water-to-binder ratios(w/b). Chloride penetration was measured by the rapid chloride permeability test (RCPT)-ASTM C1202, 150-days ponding test and alternate wetting and drying test by cyclic loading with salt solution and oven drying, and the results by the three test methods were compared. This paper discussed the effects of mineral admixtures and w/b on the concrete chloride permeability. Blending concrete with blast furnace slag, fly ash or silica fume was beneficial with regard to the resistance against chloride ion penetration. Concrete specimens with lower w/b showed lower chloride permeability.


2013 ◽  
Vol 325-326 ◽  
pp. 67-70
Author(s):  
Yun Feng Li ◽  
Mi Xue Han ◽  
Li Xu

The mineral admixtures mixed into concrete have important effects on concrete performance. The workability and mechanical properties of the concrete are studied with different dosages of admixtures, such as steel slag powder, blast furnace slag powder and fly ash. The results show that fly ash has more advantages in improving the performance of the concrete. When steel slag powder, blast furnace slag powder and fly ash, respectively, replace the amount of cement to 30%, 30%, 20%, the mechanical properties of the concrete are improved significantly.


2009 ◽  
Vol 405-406 ◽  
pp. 142-148
Author(s):  
Dong Min Wang ◽  
Yan Feng Zuo ◽  
Wei Feng Xiong

Naphthalene sulfate based superplasticizer and poly carboxylate superplasticizer (characterized by different polymerization of graft chain and backbone chain, different reaction temperature and different carboxyl/graft chain ratio) were applied to investigate their influences on fluidity of mineral admixtures (fly ash, granulated ground iron blast furnace slag, silica fume) -Portland cement-water system.


2020 ◽  
Vol 2 (3) ◽  
pp. 128-133
Author(s):  
Addepalli Mallinadh Kashyap ◽  
Tanimki Chandra Sekhar Rao ◽  
N.V.Ramana Rao

The utilisation of pozzolanic materials as the replacement to conventional cement material have the potentiality to mitigate the pollution caused by the émission of carbon based green house gases which are a main source for global warming problem. For every production of 1 ton of cement it was approximated that the emission of carbon based green house gases are about 1 ton. Keeping this in view, a new material called Geopolymer which was first coined by Davidovits has gained a lot of interest by the researchers. In this study, different molarity variations of NaOH in the order of 4M, 6M, 8M, 10M, 12M and 14M and also the blending of  mineral admixtures like Fly Ash and Ground Granulated Blast Furnace Slag with percentages (50%+50%) and the mechanical properties of normal M30 and high strength grade M70 binary blended Geopolymer concrete were studied after 28 days of ambient curing and were reported. The test results revealed that the effect of molar concentration of NaOH at 12 M is effective and the optimum replacement of mineral composition of source materials is (50%+50%) fly ash and ground granulated blast furnace slag.  


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