Physical, mechanical, and durability properties of gypsum–Portland cement–natural pozzolan blends

2001 ◽  
Vol 28 (3) ◽  
pp. 375-382 ◽  
Author(s):  
Adnan Çolak
Keyword(s):  
Portland Cement ◽  
Water Absorption ◽  
Setting Time ◽  
Strength Loss ◽  
Natural Pozzolan ◽  
Durability Properties ◽  
Gypsum Content ◽  
Mechanical Durability ◽  
Binder Ratio ◽  
Cement Binder

This paper deals with the effect of gypsum–Portland cement and gypsum–Portland cement–natural pozzolan ratios on the physical, mechanical, and durability properties of gypsum–Portland cement–natural pozzolan blends. The results indicate that the setting time of these paste decreases with the increase of gypsum content in the mixture, ranging from 8 to 11 min. The addition of superplasticizer increases the setting time from approximately 11 to 35 min. This increase is greatly dependent on the plasticizer admixture dosage. These blends show a kinetic of capillary water absorption very similar to that of the Portland cement binder. Sorptivity is strongly influenced by the type of binder, binder composition and water–binder ratio. Porosity of blended gypsum binders ranges from 12% to 37%. Their water absorption is high, reaching 27% in the blends with a greater proportion of gypsum. The gypsum–Portland cement blends themselves possess good water resistance, which is further enhanced by the addition of natural pozzolan and superplasticizer. The water-cured blends with the composition of 41:41:18 (gypsum : Portland cement : natural pozzolan) and 41:41:18S1 (gypsum : Portland cement : natural pozzolan : 1% superplasticizer) offer a compressive strength of approximately 20 MPa at room temperature. These blends give excellent properties retention after aging in water at 20°C for 95 days. Their good resistance to water decreases as the gypsum content in the mixture is raised. However, the strength loss for the gypsum–Portland cement–natural pozzolan blends is generally less than that observed for the gypsum binder.Key words: gypsum, Portland cement, natural pozzolan, physical, mechanical, durability.

Setting Behaviour of Phosphate Cement

2011 ◽  
Vol 194-196 ◽  
pp. 853-857
Author(s):  
Zhong Hua Li ◽  
He Fei Gao ◽  
Shu Rong Feng ◽  
Chao Su
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Influencing Factors ◽  
Setting Time ◽  
Repair Material ◽  
Rapid Repair ◽  
Binder Ratio

For the situation that concrete engineering required rapid and timely repair after nature disaster, setting time and influencing factors of phosphate rapid repair material were studied in this paper. The results showed that setting time of phosphate rapid repair material increased a little with increase of water and binder ratio but the setting time was short. When water and binder ratio was less than 0.20 setting time was less than 3min. Setting time was shorted with reducing of P/M. Setting time was from 2min30s to 5min when P/M was reduced from 1:0.6 to 1:4. Setting time of phosphate cement increase a little mixed with fly ash, slag or portland cement but effect of their content on setting time was little. Setting time of phosphate rapid repair material increased with increase of B/M. When content was greated than 12% the setting time was longer than 20min. Fly ash, slag and portland cement can reduce setting time of phosphate cement with borax obviously.

scholarly journals Characteristics of Wood Ash Cement Mortar Incorporating Green-Synthesized Nano-TiO2

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Bolanle Deborah Ikotun ◽  
Akeem Ayinde Raheem
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Setting Time ◽  
Wood Ash ◽  
Partial Replacement ◽  
Nano Tio2 ◽  
Setting Times ◽  
Binder Ratio ◽  
Water To Binder Ratio

AbstractThis paper presents the findings of an investigation into the influence of green-synthesized nano-TiO2 on the characteristics of wood ash (WA) cement mortar. Mortar specimens were prepared by partial replacement of cement with WA (10% by weight) and addition of 1, 2 and 3% nano-TiO2 by weight of binder; using constant water-to-binder ratio (w/b) for all mixtures. The properties evaluated are setting time of the binder and flexural and compressive strength with water absorption of the mortar. The results indicated that addition of 1 and 2% nano-TiO2 reduced setting times of WA cement paste. Also, the flexural and compressive strength of WA cement mortar were higher with the incorporation of up to 2% nano-TiO2. The water absorption of WA cement mortar was reduced when nano-TiO2 was added with 2% incorporation having the best result. The incorporation of NT in WA cement mortar improved its workability and strength characteristics.

scholarly journals EVALUATION OF WATER HYACINTH STEM ASH AS POZZOLANIC MATERIAL FOR USE IN BLENDED CEMENT

2016 ◽  
Vol 7 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Neelu Das ◽  
Shashikant Singh
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Water Hyacinth ◽  
Setting Time ◽  
Blended Cement ◽  
Partial Replacement ◽  
Test Results ◽  
Pozzolanic Material ◽  
Time Specific

 In this paper, the potential use of water hyacinth stem ash (WHA) in the partial replacement of cement is studied. WHA was used as a replacement for ordinary Portland cement at 10, 15, 20 and 25 wt. %. To evaluate the pozzolanic activity of WHA, the properties investigated were chemical composition, particle size, soundness, setting time, specific gravity, presence of crystalline matter, compressive strength, water absorption and sorption. Mortar cubes were tested for compressive strength up to the age of 56 days, whereas water absorption and sorption tests are carried out at the age of 28 days. Test results reveal that mortar cubes with 10% WHA substitution for Portland cement produced comparative compressive strength values to control mortar. It was also observed that the use of WHA in Portland cement has reduced water absorption characteristics.

Novel Geopolymers Incorporating Wollastonite and Recycled Mixed Plastics

2015 ◽  
Vol 1129 ◽  
pp. 39-48
Author(s):  
S.F. Wong ◽  
S.K. Ting ◽  
M. Lin ◽  
M. Shamini ◽  
B.K. Tay
Keyword(s):  
Thermal Properties ◽  
Water Absorption ◽  
Magnesium Oxide ◽  
High Density Polyethylene ◽  
Setting Time ◽  
High Density ◽  
Molar Ratio ◽  
Binder Ratio ◽  
Monopotassium Phosphate ◽  
Compressive And Flexural Strengths

This paper reports a study on novel geopolymers, focusing on chemically bonded composites, by incorporating wollastonite and recycled mixed plastics. Magnesium oxide and monopotassium phosphate were used as binders; while the recycled mixed plastics consisted of high-density polyethylene and polystyrene at different volume ratios. The effects of molar ratio (magnesium-to-phosphorus ratio), wollastonite-to-binder ratio and recycled mixed plastics content were investigated. The performance of geopolymers was evaluated based on their setting time and water absorption, compressive and flexural strengths as well as thermal properties.

scholarly journals NaOH Molarity's Impacts on SCGC's Workability and Durability with Ecologically Friendly Industrial By-Products

2020 ◽  
Vol 9 (3) ◽  
pp. 2370-2378
Keyword(s):  
Fly Ash ◽  
Water Absorption ◽  
Sulphuric Acid ◽  
Experimental Result ◽  
Acid Attack ◽  
Durability Properties ◽  
Slump Flow ◽  
Binder Ratio ◽  
Strength And Durability ◽  
Sulphuric Acid Medium

The objective of the analysis is to investigate the workability and durability properties of self-compacting geopolymer concrete (SCGC) based on fly ash and GGBS on various NaOH molarities. A system of trial and error was employed to achieve the SCGC mix ratio. By conducting workability properties test such as slump flow, T50 slump flow, V-funnel, and L-box and At 28, 56 and 90 days, durability properties such as water absorption, sulphuric acid attack and sorptivity were tested. The specimens have been cured for 24 hours in the oven at 70 ° C, and environmental healing is accompanied by the test days respectively. For all the molarities including 8, 10 and 12 M with a constant binding content of 400 kg / m3, the fly ash mass fraction was changed by GGBS by 0, 30, 50, and 70 per cent by weight. In all molarities, the fluid to binder ratio of 0.47 by mass has been kept constant and the S.P dosage has remained consistent with 0% replacement and 4% with 30, 50 and 70% replacement and the water content has therefore changed accordingly. The experimental result showed lower workability parameters such as slump flow and L-box ratios with increased molarity and GGBS content, increased T50 slump flow and increased V-Funnel with increased molarity and GGBS content, and the whole study was performed as suggested by the EFNARC guidelines. Durability properties such as water absorption and sorptiveness have shown good resistance with an increase of the GGBS content and an increase in molarity. Seventy percent fly-ash replacement by GGBS showed more strength degradation when held at 5percent concentration in the sulphuric acid medium. Hence SCGC can be a better replacement for normal OPC concrete both in terms of strength and durability with reduced CO2 emission.

Influence of Limestone Powder on the Optimum Gypsum Content for Portland Cement with Different Alumina Content

2007 ◽  
Vol 18 (2) ◽  
pp. 103-113 ◽  
Author(s):  
Hiroki Yamashita ◽  
Kazuo Yamada ◽  
Hiroshi Hirao ◽  
Seiichi Hoshino
Keyword(s):  
Portland Cement ◽  
Limestone Powder ◽  
Alumina Content ◽  
Gypsum Content

scholarly journals The potential use of pumice in mine backfill

2020 ◽  
Vol 1 ◽  
Author(s):  
Mohammed A. Hefni
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Mining Industry ◽  
Strength Development ◽  
Natural Pozzolan ◽  
Mine Backfill ◽  
Natural Pozzolans ◽  
Cemented Backfill ◽  
Compressive Strength Development ◽  
Potential Use

Abstract The use of natural pozzolans in concrete applications is gaining more attention because of the associated environmental, economic, and technical benefits. In this study, reference cemented mine backfill samples were prepared using Portland cement, and experimental samples were prepared by partially replacing Portland cement with 10 or 20 wt.% fly ash as a byproduct (artificial) pozzolan or pumice as a natural pozzolan. Samples were cured for 7, 14, and 28 days to investigate uniaxial compressive strength development. Backfill samples containing 10 wt.% pumice had almost a similar compressive strength as reference samples. There is strong potential for pumice to be used in cemented backfill to minimize costs, improve backfill properties, and promote the sustainability of the mining industry.

Study on Waterproof and Water-Resistant Properties of Gypsum

2012 ◽  
Vol 476-478 ◽  
pp. 1585-1588
Author(s):  
Hong Pan ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Ordinary Portland Cement ◽  
Experimental Results ◽  
Softening Coefficient

The comprehensively modified effect of cement, VAE emulsion and self-made acrylic varnish on mechanical and water-resistant properties of gypsum sample was investigated and microstructure of gypsum sample was analyzed. Experimental results exhibit that absolutely dry flexural strength, absolutely dry compressive strength, water absorption and softening coefficient of gypsum specimen with admixture of 10% ordinary Portland cement and 6% VAE emulsion and acrylic varnish coated on its surface can respectively reach to 5.11MPa , 10.49 MPa, 8.32% and 0.63, respectively.

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