scholarly journals Synthesis of Geopolymer from Inorganic Construction Waste

2013 ◽  
Vol 30 ◽  
pp. 45-51 ◽  
Author(s):  
Arbind Pathak ◽  
Vinay Kumar Jha
Keyword(s):  
Compressive Strength ◽  
Coal Fly Ash ◽  
Chemical Society ◽  
Raw Material ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Curing Time ◽  
Mass Ratio ◽  
Construction Waste ◽  
Alumino Silicate

Recently, the demolition of old houses and the construction of new buildings in Kathmandu valley are in the peak which in turn generates a huge amount of construction waste. There are two major types of construction wastes which are burden for disposal namely cement-sand-waste (CSW) and the coal fly ash (CFA). These construction wastes are rich source of alumino-silicate and thus used as raw material for the synthesis of geopolymer in this study. Geopolymers have been synthesized from CSW and CFA using NaOH-KOH and Na2SiO3 as activators. Some parameters like alkali concentration, amount of Na2SiO3 and curing time have been varied in order to improve the quality of geopolymeric product. The geopolymerization process has been carried out using 3-8M KOH/NaOH solutions, Na2SiO3 to CFA and CSW mass ratio of 0.25-2.00 and curing time variation from 5-28 days. The curing temperature was fixed at 40ºC in all the cases. 6M NaOH and 7M KOH solutions were found appropriate alkali concentrations while the ratio of sodium silicate to CSW and CFA of 0.5 and 1.75 respectively were found suitable mass ratio for the process of geopolymer synthesis. The maximum compressive strength of only 7.3 MPa after 15 days curing time with CSW raw material was achieved while with CFA, the compressive strength was found to be 41.9 MPa with increasing the curing time up to 28 days.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9334Journal of Nepal Chemical Society Vol. 30, 2012 Page:  45-51 Uploaded date: 12/16/2013    

scholarly journals A Laboratory Scale Synthesis of Geopolymer from Locally Available Coal Fly Ash from Brick Industry

2013 ◽  
Vol 29 ◽  
pp. 18-23
Author(s):  
Rishi Babu Bhandari ◽  
Arvind Pathak ◽  
Vinay Kumar Jha
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Time Variation ◽  
Coal Fly Ash ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Curing Time ◽  
Mass Ratio ◽  
Maximum Compressive Strength

In this work, geopolymers have been synthesized from coal fly ash (CFA) using KOH and Na2SiO3 as activators. Some parameters such as alkali concentration, amount of Na2SiO3 and curing time have been varied in order to improve the quality of geopolymeric product. The geopolymerization process was carried out using 3-8 M KOH solutions, Na2SiO3 to CFA mass ratio of 0.25-2.00 and curing time variation from 6-28 days. The curing temperature was fixed at 40°C in all the cases. During the variation of KOH concentration, the maximum compressive strength of 6.62 MPa was obtained with CFA treated with 7 M KOH solution. Similarly, with the variation of the mass ratio of Na2SiO3 to CFA, the maximum compressive strength of 28.1 MPa was obtained with Na2SiO3 to CFA mass ratio of 1.75. Furthermore, the compressive strength was found to be increased with increasing curing time and 41.9 MPa was achieved with 28 days of curing time. DOI: http://dx.doi.org/10.3126/jncs.v29i0.9232Journal of Nepal Chemical SocietyVol. 29, 2012Page: 18-23Uploaded date : 12/3/2013 

scholarly journals Synthesis of Geopolymer from Coal Fly Ash

2013 ◽  
Vol 30 ◽  
pp. 24-28
Author(s):  
Vinay Kumar Jha ◽  
Gautam Prasad Budhamagar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
Chemical Society ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Curing Time ◽  
Naoh Solution ◽  
Maximum Compressive Strength

In the present work, geopolymers have been synthesized from coal fly ash (CFA) using NaOH and Na2SiO3 as activators. Some parameters like alkali concentration, amount of Na2SiO3 and curing time have been varied in order to improve the quality of geopolymeric product. The geopolymerization process has been performed using 3-8M NaOH solutions, Na2SiO3 to CFA mass ratios of 0.25-1.25 and curing time variation from 5-15 days. The curing temperature was fixed at 40ºC in all cases. In the variation of NaOH concentration, the maximum compressive strength of 2.3 MPa was obtained with CFA treated with 6M NaOH solution. Similarly during the variation of amount of Na2SiO3, the maximum compressive strength of 17.6 MPa was obtained with Na2SiO3 to CFA mass ratio of 1.25. Furthermore, the compressive strength was found increasing up to 20.3 MPa with increasing curing time.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9331Journal of Nepal Chemical Society Vol. 30, 2012 Page:  24-28 Uploaded date: 12/16/2013 

scholarly journals An Attempt of Geopolymer Synthesis from Construction Waste

2013 ◽  
Vol 28 ◽  
pp. 29-33 ◽  
Author(s):  
Vinay Kumar Jha ◽  
Anupama Tuladhar
Keyword(s):  
Chemical Society ◽  
Raw Material ◽  
Alkali Concentration ◽  
Kathmandu Valley ◽  
Curing Time ◽  
Huge Amount ◽  
Construction Waste ◽  
Alumino Silicate ◽  
New Buildings

Recently, the demolition of old houses and the construction of new buildings in Kathmandu valley are in the peak which in turn generates a huge amount of construction waste. This construction waste is rich source of alumino-silicate and thus used as raw material for the synthesis of geopolymer in this study. Geopolymers have been synthesized from construction waste using NaOH and Na2SiO3 as activators. Some parameters like alkali concentration, ratio of Na2SiO3 to construction waste and curing time have been varied in order to improve the quality of geopolymeric product. The results obtained revealed the maximum compressive strength of 7.3 MPa at the ratio of sodium silicate to construction waste of 0.5 (w/w) on 15 days curing time at 40ºC temperature. DOI: http://dx.doi.org/10.3126/jncs.v28i0.8038Journal of Nepal Chemical Society Vol.28, 2011 Page 29-33 Uploaded date: March 6, 2013

Study on Preparation of Construction Waste Paving Brick

2013 ◽  
Vol 712-715 ◽  
pp. 913-916
Author(s):  
Lan Xi Wang ◽  
Guang Hui Pan ◽  
Fu Yong Li ◽  
Hai Ming Wang ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Raw Material ◽  
Recycled Aggregate ◽  
Analysis Method ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Orthogonal Analysis

The construction waste was processed into recycled aggregate to produce paving brick with grade of Cc40. The influences of raw material ratio on the compressive strength of construction waste paving brick were studied with orthogonal analysis method. The results show that the optimum raw material ratio are as follows: mass ratio of recycled aggregate to cement is 3.0, water cement ratio 0.30, compound activator 1.1% (mass fraction of cement, the same below), interfacial agent 0.6%, and water reducing agent of 0.5%. In addition, mechanisms of the admixtures were further studied by SEM and EDS.

Effect of Bentonite Addition on Geopolymer Concrete from Geothermal Silica

2016 ◽  
Vol 841 ◽  
pp. 7-15 ◽  
Author(s):  
Himawan Tri Bayu Murti Petrus ◽  
Joshepine Hulu ◽  
Gede S.P. Dalton ◽  
Elsa Malinda ◽  
Rizal Agung Prakosa
Keyword(s):  
Compressive Strength ◽  
Room Temperature ◽  
Sem Analysis ◽  
Strength Test ◽  
Raw Material ◽  
Curing Temperature ◽  
Curing Time ◽  
Compressive Strength Test ◽  
Temperature Optimization ◽  
Alkaline Activator

Silica scaling is one of major problems in geothermal power plant. Silica recovery is a promising method to solve this particular problem in regard to silica utilization as geopolimer concrete. In this experimental study, bentonite was used as raw alumina source. Experiments were conducted by means observing the geopolymerization through alkaline activator ratio, raw material ratio, and temperature optimization. After mixing and casting for 24 hours, samples were cured at 80°C, 100°C, and 120°C for certain period of time and kept at room temperature for 7 days before compressive strength test. The optimum curing time and temperature gained from this experiment were 120 minutes and 100°C with compressive strength of 29.16 MPa. The development of geopolymer bond and microstructure of samples were then investigated by SEM technique. Scanning electron microscopy (SEM) analysis also showed better improvement in geopolymer layer of concrete sample with increasing curing temperature.

Study on Preparation of Solid Concrete Brick with Recycled Aggregate

2013 ◽  
Vol 648 ◽  
pp. 108-111
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Recycled Aggregate ◽  
Preparation Process ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimal Value

The construction waste was processed into recycled aggregate to produce solid construction waste brick with grade of MU20. The preparation process of recycled aggregate and the optimal value of mass ratio of water to cement (water cement ratio) and mass ratio of recycled aggregate to cement was studied. The results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5MPa and can be satisfied with the requirement of MU20 solid concrete brick.

Effect of Curing Regimes on Metakaolin Geopolymer Pastes Produced from Geopolymer Powder

2012 ◽  
Vol 626 ◽  
pp. 931-936 ◽  
Author(s):  
Liew Yun Ming ◽  
Kamarudin Hussin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Mohammed Binhussain ◽  
Luqman Musa ◽  
...  
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Solidification Process ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Strength Development ◽  
Curing Time ◽  
Curing Conditions ◽  
Metakaolin Geopolymer ◽  
Geopolymer Paste

The properties of metakaolin geopolymer paste are affected by the alkali concentration, the initial raw materials, solidification process, and amount of mixing water as well as the curing conditions. This study aimed to investigate the effect of curing temperature (room temperature, 40°C, 60°C, 80°C and 100°C) and curing time (6h, 12h, 24h, 48h and 72h) on the geopolymer pastes produced from geopolymer powder. The results showed that curing at room temperature was unfeasible. Heat was required for the geopolymerization process, where strength increased as the curing temperature was increased. Moderate elevated curing temperature favored the strength development of geopolymer pastes in comparison with those treated with extreme elevated curing temperature. When geopolymer paste was subjected to extreme elevated curing temperature, shorter curing time should be used to avoid deterioration in strength gain. Similarly, longer curing time was recommended for moderate elevated curing temperature. The microstructure of geopolymer paste cured at moderate curing temperature showed obvious densification of structure. In contrast, the structure formed was weak and less compact at very high elevated curing temperature.

Use of Sugarcane Bagasse Ash as Raw Material in Production of Autoclaved Lightweight Concrete

2013 ◽  
Vol 652-654 ◽  
pp. 1242-1246
Author(s):  
Arkarin Apiwaranuwat ◽  
Preung Kitratporn ◽  
Kannaree Chuangcham ◽  
Thantip Punmatharith
Keyword(s):  
Compressive Strength ◽  
Sugarcane Bagasse ◽  
Lightweight Concrete ◽  
Raw Material ◽  
Curing Time ◽  
Optimal Production ◽  
Sugarcane Bagasse Ash ◽  
Total Composition ◽  
Maximum Compressive Strength ◽  
Production Conditions

Sugarcane bagasse ash (ScBA) obtained as a byproduct of sugar processing may be used as a raw material for producing autoclaved lightweight concrete (ALC). We examined the chemical composition and physical properties of ScBA and determined that the material is not hazardous as defined by the Thai Ministry of Industry. The optimal production conditions for ScBA-containing ALC were a cement/sand ratio of 65/36, a water/total composition ratio of 0.24, and a curing time of 16 h. Maximum compressive strength was obtained in samples containing 20 wt% ScBA.

Effects of Microstructure on Fracture Behavior of Hardened Cement Paste

1994 ◽  
Vol 370 ◽  
Author(s):  
Asif Ahmed ◽  
Leslie Struble
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Fracture Behavior ◽  
Curing Temperature ◽  
Hardened Cement ◽  
Curing Time ◽  
Hardened Cement Paste ◽  
Fracture Parameters ◽  
Initial Hypothesis

AbstractMechanical properties of any material, including hardened cement paste, are assumed to be controlled by its microstructure. An attempt has been made here to establish a link between bulk fracture parameters of hardened cement paste and its microstructure. Paste microstructure has been varied by changing the initial w/c ratio, curing time and curing temperature, and by addition of chemicals to change the calcium hydroxide morphology. It has been found that, like compressive strength, fracture parameters depend directly on porosity. Contrary to our initial hypothesis, CH morphology was found to have no effect on the fracture parameters.

scholarly journals Factors Affecting Alkali Activation of Laterite Acid Leaching Residues

Environments ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 4
Author(s):  
Konstantinos Komnitsas ◽  
Georgios Bartzas ◽  
Vasiliki Karmali ◽  
Evangelos Petrakis
Keyword(s):  
Compressive Strength ◽  
Environmental Sustainability ◽  
Structural Integrity ◽  
Acid Leaching ◽  
Sodium Silicate Solution ◽  
Curing Temperature ◽  
Alkali Activation ◽  
Curing Time ◽  
Synthesis Conditions ◽  
Alkali Activated

In this experimental study, the alkali activation of acid leaching residues using a mixture of sodium hydroxide (NaOH) and alkaline sodium silicate solution (Na2SiO3) as activators is investigated. The residues were also calcined at 800 and 1000 °C for 2 h or mixed with metakaolin (MK) in order to increase their reactivity. The effect of several parameters, namely the H2O/Na2O and SiO2/Na2O ratios present in the activating solution, the pre–curing time (4–24 h), the curing temperature (40–80 °C), the curing time (24 or 48 h), and the ageing period (7–28 days) on the properties of the produced alkali activated materials (AAMs), including compressive strength, porosity, water absorption, and density, was explored. Analytical techniques, namely X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and elemental mapping analysis were used for the identification of the morphology and structure of the final products. The experimental results show that the laterite acid leaching residues cannot be alkali activated in an unaltered state, and the compressive strength of the produced AAMs barely reaches 1.4 MPa, while the mixing of the residues with 10 wt% metakaolin results in noticeably higher compressive strength (41 MPa). Moreover, the calcination of residues at 800 and 1000 °C has practically no beneficial effect on alkali activation. Alkali activated materials produced under the optimum synthesis conditions were subjected to high temperature firing for 2 h and immersed in distilled water or acidic solution (1 mol L−1 HCl) for 7 and 30 days in order to assess their structural integrity under different environmental conditions. This study explores the potential of alkali activation of laterite leaching residues amended with the addition of metakaolin for the production of AAMS that can be used as binders or in several construction applications in order to enable their valorization and also improve the environmental sustainability of the metallurgical sector.

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