Influence of Mineral Admixtures on Mortar Brittleness

2010 ◽  
Vol 168-170 ◽  
pp. 281-285
Author(s):  
Ben Lin Xiao ◽  
Li Hua Li ◽  
Hui Ming Tang

The influence of mineral admixtures on mortar brittleness is analysed in this paper. Test results show that the mortar brittleness increases with the increasing of compressive strength and the passage of age. When the content of binding materials rises, the compressive strength also increases, but the brittleness decreases at the same time. The more the content of fly ash is, the more the brittleness falls. Silica fume added can not only enhance compressive strength but also reduce brittleness of the mortar. MgO added can cut down the brittleness, but can reduce the compressive strength a little at the same time, especially for early compressive strength.

2019 ◽  
Vol 9 (9) ◽  
pp. 1049-1054
Author(s):  
Yunxia Lun ◽  
Fangfang Zheng

This study is aimed at exploring the effect of steel slag powder (SSP), fly ash (FA), and silica fume (SF) on the mechanical properties and durability of cement mortar. SSP, SF, and FA were used as partial replacement of the Ordinary Portland cement (OPC). It was showed that the compressive and bending strength of steel slag powder were slightly lower than that of OPC. An increase in the SSP content caused a decrease in strength. However, the growth rate of compressive strength of SSP2 (20% replacement by the weight of OPC) at the curing ages of 90 days was about 8% higher than that of OPC, and the durability of SSP2 was better than that of OPC. The combination of mineral admixtures improved the later strength, water impermeability, and sulfate resistance compared with OPC and SSP2. The compressive strength of SSPFA (SSP and SF) at 90 days reached 70.3 MPa. The results of X-ray diffraction patterns and scanning electron microscopy indicated that SSP played a synergistic role with FA or SF to improve the performance of cement mortar.


2013 ◽  
Vol 652-654 ◽  
pp. 1181-1184
Author(s):  
Guo Qiang Xu ◽  
Zhi Guo You ◽  
Lin Gao ◽  
Dian Li Han

The influence of admixture of super-fine limestone powder and low-quality fly ash in different proportions on the fluidity and strength of cement mortar is studied. The test results show that the mortar fluidity increases with the increase of the super-fine limestone powder (the mixing amount of fly ash reduces), and the strength of cement mortar can improve when limestone powder and low-quality fly ash are combined admixed to a certain ratio. The maximum flexural strength of the 28d mortar is 9.8MPa and its maximum compressive strength is 42.2MPa, and at this time, the limestone powder accounts for 33.3% of the mineral admixtures. However, when the mixing amount of super-fine limestone powder is over a certain range, the strength of 28d cement mortar will reduce.


2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.


2013 ◽  
Vol 723 ◽  
pp. 298-302
Author(s):  
An Cheng ◽  
Wei Ting Lin ◽  
Sao Jeng Chao ◽  
Hui Mi Hsu ◽  
Chin Cheng Huang

This study investigated the influence of individual constituents of calcined shale or hybrid constituents of calcined shale and fly ash or silica fume on the workability and compressive strength. Calcined shale is heat treated in a kiln and then ground to a finer powder and the calcination temperatures of 800 °C were used. The test results demonstrated that the workability and compressive strength decreased with the inclusion of calcined shale increased and the compressive strength of the specimens containing calcined shale all lower than that of the control specimens. It might be due to the higher water demand and lower CaO value. However, the hybrid batches with calcined shale and fly ash or silica fume enhanced better performance on compressive strength than individual constituents of calcined shale. The combination of 10 % calcined shale and 10 % silica fume in concrete seemed to give superior compressive strength and gave the highest value in the testing series. Finally, the inclusion of calcined shale is help to reduce the emissions of CO2and revealed an ecological advantage for concrete containing a binder blend of cement and calcined shale.


2018 ◽  
Vol 765 ◽  
pp. 285-289
Author(s):  
Osama Ahmed Mohamed ◽  
Waddah Al Hawat ◽  
Omar Fawwaz Najm

Supplementary cementitious materials such as fly ash, silica fume and ground granulated blast furnace slag (GGBS) have been used widely to partially replace cement in producing self-consolidating concrete (SCC). The production of cement is associated with emission of significant amounts of CO2 and increases the human footprint on the environment. Fly ash, silica fume, and GGBS are recycled industrial by-products that also impart favorable fresh and hardened properties on concrete. This study aims to assess the effect of the amounts of fly ash and silica fume on strength and chloride penetration resistance of concrete. Rapid Chloride Penetration Test (RCPT) was used to assess the ability of SCC to resist ingress of chlorides into concrete. SCC mixes with different dosages of fly ash and silica fume were developed and tested at different curing ages. Test results showed that replacing 20% of cement with fly ash produced the highest compressive strength of 67.96 MPa among all fly ash-cement binary mixes. Results also showed that replacing15% of cement with silica fume produced the highest compressive strength of 95.3 MPa among fly ash-cement binary mixes. Using fly ash and silica fume consistently increased the concrete resistance to chloride penetration at the early ages. Silica fume at all dosages results in low or very low levels of chloride penetration at all curing ages of concrete.


2014 ◽  
Vol 936 ◽  
pp. 1409-1413 ◽  
Author(s):  
Lin Chun Zhang ◽  
Ai Lian Zhang

The Marsh cone method and rotary viscosimeter are used to study the effect of mineral admixtures such as ultra-fine fly ash, ultra-fine slag, zeolite powder and silica fume on rheological properties of cement paste. Test results show that the optimal ratio of ultra-fine fly ash, ultra-fine slag, zeolite powder and silica fume are respectively 20%, 20%, 10% and 8%. And the optimized mix proportion is the composition of 8% silica fume and 12% slag. By using water reducing agent and mineral admixtures we could get the cement paste which has good liquidity and no bleeding.


2012 ◽  
Vol 598 ◽  
pp. 612-617 ◽  
Author(s):  
Ying Li ◽  
Da Hu Dai

In order to improve the microstructure of recycled concrete, the mineral admixtures were mixed into recycled concrete by different mixing method in this paper. It is demonstrated that the early compressive strength of recycled concrete decreased when mixed by fly ash only, but its later strength increasing rate is higher than recycled concrete without fly ash. When mixed fly ash and silica fume in the recycled concrete, the compressive strength of recycled concrete with fly ash and silica fume is higher than the strength of recycled concrete with fly ash only, and its microstructure tend to be dense.


2015 ◽  
Vol 1095 ◽  
pp. 248-253 ◽  
Author(s):  
Yuan Gang Wang ◽  
Peng Ma ◽  
Kai Jian Huang ◽  
Gao Qin Zhang ◽  
Ya Feng Hu

Fly ash, silica fume and ground steel slag are chosen to make up composite mineral admixtures. Through the orthogonal test, carbonization resistance property of High Performance Concrete (HPC) mixed with composite mineral admixtures is studied. Test results show that the carbonization resistance property of HPC can be improved with defined amount of composite mineral admixture mixed, in addition, the effect of ternary composite admixture of ground steel slag, fly ash and silica fume is more obvious than that of binary composite admixture.


2016 ◽  
Vol 692 ◽  
pp. 74-81 ◽  
Author(s):  
J.R. Thirumal ◽  
R. Harish

Self – compacting concrete (SCC) is a high – performance concrete that can flow under its own weight to completely fill the form work and self-consolidation without any mechanical vibration. Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction. Such concrete can accelerate the placement, reduce the labor requirements needed for consolidation, finishing and eliminate environmental pollution. One alternative to reduce the cost of self-compacting concrete is the use of mineral admixtures such as silica fume, ground granulated blast furnace slag and fly ash, which is finely, divided materials added to concrete during mixture procedure .When mineral admixtures replace a part of the Portland cement, the cost of self-compacting concrete will be reduced especially if the mineral admixtures are waste or industrial by-product. The various tests for compressive, tensile and flexural strength are determined for various specimens with certain percentages ( 10 % ,30 % ) of replacement like silica fume, fly ash and combination of both fly ash and silica fume. Admixture combination of fly ash and silica fume replacing 30 % results in maximum compressive strength. Admixture of fly ash replacing 10 % results in maximum tensile and flexural strength. In order to make SCC effective, trials can be made with partial replacement of combining silica fume and fly ash to achieve the higher compressive strength. Minimum replacement of fly ash can be investigated to achieve higher tensile and flexural strength .With respect to the above combination of replacement SCC can be dealt with its several specializations to make it effective.


2018 ◽  
Vol 17 (9) ◽  
pp. 2023-2030
Author(s):  
Arnon Chaipanich ◽  
Chalermphan Narattha ◽  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn

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