Packing Density Improvement for Improving Strength of Cement Paste

2019 ◽  
Vol 943 ◽  
pp. 124-128 ◽  
Author(s):  
Jian Jian Chen ◽  
Hong Niao Chen ◽  
Gu Li
Keyword(s):  
Silica Fume ◽  
Packing Density ◽  
Water Film ◽  
High Strength ◽  
Cementitious Materials ◽  
Maximum Strength ◽  
Depth Analysis ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash

To design a mix for high-strength concrete is not easy, one of the methods is to improve the packing density of the cementitious materials. To study the effect of packing density on strength, a comprehensive research program using superfine pulverized fuel ash and silica fume was carried out. Results showed that a high superfine pulverized fuel ash and silica fume ratios could result in a lower optimum W/CM ratio for maximum strength. Depth analysis illustrated that the optimum water film thickness for maximum strength is always at around 0.01 to 0.05 μm, regardless of the SPFA and SF ratios.

EFFECT OF CERAMIC AGGREGATE ON HIGH STRENGTH MULTI BLENDED ASH GEOPOLYMER MORTAR

2015 ◽  
Vol 77 (16) ◽  
Author(s):  
Mohd Azreen Ariffin ◽  
Mohd Warid Hussin ◽  
Mostafa Samadi ◽  
Nor Hasanah Abdul Shukor Lim ◽  
Jahangir Mirza ◽  
...  
Keyword(s):  
Alkaline Solution ◽  
High Strength ◽  
Fine Aggregate ◽  
Palm Oil Fuel Ash ◽  
Viable Solution ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Alumino Silicate ◽  
Pulverized Fuel Ash ◽  
Oil Fuel

Geopolymer is a type of amorphous alumino-silicate cementitious material, synthesized by the reaction of an alumina-silicate powder with an alkaline solution. The geopolymer technology has recently attracted increasing attention as a viable solution to reuse and recycle industrial solid wastes and by-products. This paper discusses the performance of geopolymer mortar comprises of multiple blended ash of palm oil fuel ash (POFA), pulverized fuel ash (PFA) and ground granulated blast furnace slag (GGBFS) by replacing ordinary Portland cement. Fine aggregate obtained from the ceramic waste was used to partially replace normal sand in the mixture. The concentration of alkaline solution used was 14 Molar. The fresh mortar was cast in 50x50x50 mm cubes geopolymer mortar specimens and cured at ambient temperature for 24 hours. The effects of mass ratios of alkaline solution to multiple blended ashes and percentage of ceramic aggregate as sand replacement on compressive, flexural and tensile strength of mortar were examined. The results revealed that as the multi blended ash (GGBFS: PFA: POFA) mass ratio increased, the compressive strength of geopolymer mortar is increased with regards to the ceramic aggregate properties.

Triple Blending with Superfine Natural Zeolite and Condensed Silica Fume to Improve Performance of Cement Paste

2017 ◽  
Author(s):  
P.L. Ng ◽  
J.J. Chen ◽  
A.K.H. Kwan
Keyword(s):  
Silica Fume ◽  
Cement Paste ◽  
Packing Density ◽  
Natural Zeolite ◽  
Water Film ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Concrete Production ◽  
Fine Size ◽  
Condensed Silica Fume

Superfine natural zeolite (SNZ) is obtained by grinding natural zeolite to micro-fine size, whereas condensed silica fume (CSF) is by-product of ferrosilicon industry. Both SNZ and CSF are environmentally-friendly supplementary cementitious materials for mortar and concrete production. Owing to the high fineness and favourable grading of SNZ and CSF (the median particle sizes were 4 μm and 0.4 μm, respectively), the addition of SNZ and CSF could successively fill the voids between ordinary Portland cement (OPC) grains and increase the packing density of the binder, so as to reduce the volume of voids to be filled with water. Therefore, triple blending of OPC+SNZ+CSF can benefit the overall performance of cement paste by releasing more water for flowability improvement at the same water/binder (W/B) ratio, or adopting a lower W/B ratio for strength improvement at the same flowability requirement. This study evaluated the effects of adding SNZ and CSF on the packing density and water film thickness of binder. The experimental results proved that triple blending with SNZ and CSF could increase the packing density and improve the flowability and cohesiveness of cementitious paste.

Development of Magnesium-Silicate-Hydrate Cement by Pulverized Fuel Ash

2016 ◽  
Vol 709 ◽  
pp. 61-65 ◽  
Author(s):  
Ting Ting Zhang ◽  
Yan Nan Du ◽  
Yan Jie Sun ◽  
Zi Ming He ◽  
Zhen Lin Wu
Keyword(s):  
Silica Fume ◽  
Low Cost ◽  
Magnesium Silicate ◽  
Magnesium Carbonate ◽  
Hydration Reaction ◽  
Hydrated Calcium Silicate ◽  
Initial Strength ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash

Magnesium silicate hydrate (M-S-H) gel can be fabricated via the reaction of MgO with silica fume in the presence of sodium hexametaphosphate (Na-HMP). In this study, in effort to reduce the cost of the M-S-H gel system, pulverized fuel ash (PFA) was utilized as a silica source to replace silica fume. The influence of various PFA quantities on the compression strength and other properties of the M-S-H system were investigated via XRD, SEM, and TG-RTG analysis. Compressive strength was optimal when 35 wt% of silica fume was replaced. The hydration products were relatively more complex when PFA was used, containing hydrated calcium silicate, hydrated magnesium silicate, and carbonate gel, among other products. Magnesium carbonate participated in the hydration reaction process, which generated carbonated gel to form a grid structure and promoted the initial strength of the material. Taken together, the results showed that PFA can be feasibly and effectively used to form M-S-H gel cement systems at low cost.

Effects of Condensed Silica Fume and Superfine Cement on Flowability of Cement Paste

2011 ◽  
Vol 121-126 ◽  
pp. 2695-2700 ◽  
Author(s):  
A. K. H. Kwan ◽  
Jia Jian Chen ◽  
L. G. Li
Keyword(s):  
Experimental Study ◽  
Silica Fume ◽  
Cement Paste ◽  
Water Film ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Definite Effect ◽  
Wide Range ◽  
Depth Analysis ◽  
Condensed Silica Fume

Addition of supplementary cementitious materials (SCM) has been contradictorily reported to be beneficial or detrimental to the flowability of concrete and no general conclusion can be drawn up to now. In order to comprehensively disclose the effects of SCM on the flowability, an experimental study had been carried out to measure the flowability of a total of 100 cement paste samples with different condensed silica fume (CSF) and superfine cement (SFC) contents at a wide range of water/cementitious materials (W/CM) ratios. The results showed that the addition of CSF would decrease the flowability at a relatively high W/CM ratio but increase the flowability at a low W/CM ratio, while the addition of SFC could generally improve the flowability of cement paste. Joint addition of SFC and CSF would not exert any definite effect on flowability at a relatively high W/CM ratio but could improve the flowability at a low W/CM ratio. In-depth analysis showed that these results could be well explained by the theory of water film thickness.

Measurement and Prediction of Absorption of Cementitious Systems Using RILEM Vacuum Saturation Method

2011 ◽  
Vol 243-249 ◽  
pp. 156-159
Author(s):  
Iqbal Khan Mohammad
Keyword(s):  
Silica Fume ◽  
Prediction Models ◽  
Supplementary Cementitious Materials ◽  
Cement Matrix ◽  
Analytical Prediction ◽  
Vacuum Saturation ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Saturation Method ◽  
Pulverized Fuel Ash

Measurement and prediction of absorption of concrete by saturation method is presented. Measurement of absorption of concrete consisting of supplementary cementitious materials was conducted by using vacuum saturation method in accordance to RILEM. Pulverized fuel ash and silica fume were incorporated as partial cement replacements for the preparation of various combinations of cementitious composite systems. Absorption of cement matrix containing ordinary Portland cement, pulverized fuel ash and silica fume at various ages is reported. Based on the experimentally obtained results, analytical prediction models were developed. These models enabled the establishment of isoresponse contours showing the interactive influence between the various parameters investigated.

An experimental study on cyclic behaviour of reinforced concrete connections using waste materials as cement partial replacement

2019 ◽  
Vol 46 (6) ◽  
pp. 522-533
Author(s):  
Yasmin Murad ◽  
Yousef Abu-Haniyi ◽  
Ala AlKaraki ◽  
Zeid Hamadeh
Keyword(s):  
Silica Fume ◽  
Waste Materials ◽  
Partial Replacement ◽  
Cyclic Tests ◽  
Concrete Compressive Strength ◽  
Cyclic Behaviour ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Concrete Materials ◽  
Pulverized Fuel Ash

A series of cyclic tests on unconfined beam–column connections with composite concrete materials are conducted. Cement is partially replaced by waste materials using two different percentages of 15% and 20%. The proper percentage of cement replacement is found to be 15% for the pulverized fuel ash, silica fume, and iron filings. Increasing the percentage to 20% tends to relatively decrease concrete compressive strength, weaken the joint, and reduce its ductility. It is recommended using pulverized fuel ash to enhance the performance of beam–column connections under cyclic loading. Silica fume and iron filings have also enhanced the joint response, but the enhancement is most remarkable when using 15% pulverized fuel ash. The implementation of composite concrete has increased the joint’s ductility and reduced its level of damage based on the type and percentage of the implemented waste material. Furthermore, the disposal of waste materials into the concrete mix is a good solution for reducing environmental pollution.

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