Experimental investigation on the compressive strength of PFGP-covered concretes exposed to high temperature

2019 ◽  
Vol 10 (4) ◽  
pp. 399-410
Author(s):  
Amir Hamzeh Keykha
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
High Temperature ◽  
Design Methodology ◽  
Polypropylene Fiber ◽  
Content Type ◽  
Gypsum Plaster ◽  
Compressive Strength Of Concrete

Purpose This study aims to investigate the effect of high temperature (600°C) on the compressive strength of concrete covered with a mixture of polypropylene fiber and gypsum plaster (PFGP). Design/methodology/approach To study the compressive strength of concrete specimens exposed to temperature, 16 cubic specimens (size: 150 mm × 150 mm × 150 mm) were made. After 28 days of processing and gaining the required strength of specimens, first, polypropylene fiber was mixed with gypsum plaster (CaSO4.2H2O) and then the concrete specimens were covered with this mixture. To cover the concrete specimens with the PFGP, the used PFGP thickness was 15 mm or 25 mm. The polypropylene rates mixed with the gypsum plaster were 1, 3 and 5 per cent. A total of 14 specimens, 12 of which were covered with PFGP, were exposed to high temperature in two target times of 90 and 180 min. Findings The results show that the PFGP as covering materials can improve the compressive strength lost because of the heating of the concrete specimens. The results also show that the presence of polypropylene fiber in gypsum plaster has the effect on the compressive strength lost because of the heating of the PFGP-covered concrete. The cover of PFGP having 3 per cent polypropylene fiber had the best effect on remained strength of the specimens. Originality/value The cover of PFGP having 3 per cent polypropylene fiber has the best effect on remained strength of the PFGP covered specimens exposed to temperature.

Experimental Study on Sand and Cement Replacement by Termite Mound Soil

2019 ◽  
pp. 279-287
Author(s):  
Harish R ◽  
Ramesh S ◽  
Tharani A ◽  
Mageshkumar P
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Compressive Strength ◽  
Natural Environment ◽  
Fine Aggregate ◽  
Test Results ◽  
Termite Mound ◽  
Cement Concrete ◽  
Cement Ratio ◽  
Compressive Strength Of Concrete

This paper presents the results of an experimental investigation of the compressive strength of concrete cubes containing termite mound soil. The specimens were cast using M20 grade of concrete. Two mix ratios for replacement of sand and cement are of 1:1.7:2.7 and 1:1.5:2.5 (cement: sand: aggregate) with water- cement ratio of 0.45 and varying combination of termite mound soil in equal amount ranging from 30% and 40% replacing fine aggregate (sand) and cement from 10%,15%,20% were used. A total of 27 cubes, 18 cylinders and 6 beams were cast by replacing fine aggregate, specimens were cured in water for 7,14 and 28 days. The test results showed that the compressive strength of the concrete cubes increases with age and decreases with increasing percentage replacement of cement and increases with increasing the replacement of sand with termite mound soil cured in water. The study concluded that termite mound cement concrete is adequate to use for construction purposes in natural environment.

An experimental investigation of dimensional precision in uncertainty disclosures related to revenue recognition

2018 ◽  
Vol 31 (1) ◽  
pp. 90-101 ◽  
Author(s):  
Ning Du ◽  
Ray Whittington
Keyword(s):  
Decision Making ◽  
Experimental Investigation ◽  
Design Methodology ◽  
Revenue Recognition ◽  
Content Type ◽  
Dimensional Precision ◽  
Outcome Information ◽  
Disclosure Strategy ◽  
Practical Implications ◽  
Range Estimate

Purpose The purpose of this paper is to investigate how managerial disclosure of imprecise information about revenue recognition affects investors’ perceptions of corporate and management performance. Specifically, the authors focus on how outcome and probability dimensions and their respective (im) precision interact with each other and jointly affect investors’ judgments and decision-making. Design/methodology/approach The authors conducted an experiment where the dimensions are manipulated (outcome vs probability) of disclosed revenue recognition information and its related precision (a point vs a range estimate). Findings Results from this study suggest that participants are sensitive to specific dimensions of uncertainty disclosure: participants were highly aware of the (im)precision in outcome information, were more likely to invest when both dimensions were vague and expected higher revenue when dimensional precision was consistent. Practical implications The results imply that dimensional precision is an important component in uncertainty disclosure and may have a significant impact on investors’ judgments and decision making. Regulators and managers should consider dimensional imprecision when they develop and implement disclosure strategy regarding revenue recognition. Social implications The results have practical value for regulators/managers, who are in the process of developing/implementing disclosure strategy regarding revenue recognition. Originality/value This is the first study to examine the interaction of dimensions of uncertainty in revenue disclosures.

Mechanical Properties of Polypropylene Fiber Concrete after High Temperature

2014 ◽  
Vol 662 ◽  
pp. 24-28 ◽  
Author(s):  
Xi Du ◽  
You Liang Chen ◽  
Yu Chen Li ◽  
Da Xiang Nie ◽  
Ji Huang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Polypropylene Fiber ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Concrete ◽  
Compressive Strength Of Concrete ◽  
Polypropylene Fiber Reinforced Concrete

With cooling tests on polypropylene fiber reinforced concrete and plain concrete that were initially subjected to different heating temperatures, the change of mechanical properties including mass loss, uniaxial compressive strength and microstructure were analyzed. The results show that the compressive strength of concrete tend to decrease with an increase in temperature. After experiencing high temperatures, the internal fibers of the polypropylene fiber reinforced concrete melted and left a large number of voids in it, thereby deteriorating the mechanical properties of concrete.

Experimental Study of Compression for Multi-Scale Polypropylene Fiber Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 1584-1588 ◽  
Author(s):  
Ning Hui Liang ◽  
Xin Rong Liu ◽  
Ji Sun
Keyword(s):  
Compressive Strength ◽  
Polypropylene Fiber ◽  
Plain Concrete ◽  
Compression Tests ◽  
Concrete Compressive Strength ◽  
Hybrid Fiber ◽  
Multi Scale ◽  
Fine Fiber ◽  
Fiber Concrete ◽  
Compressive Strength Of Concrete

Through compression tests on 30 plain concrete and polypropylene fiber concrete specimens with the dimensions of 100mm × 100mm × 100mm , studied the influence of the different scales of polypropylene fiber and hybrid fiber on concrete compressive strength and compressive deformation. The results showed that: the compressive strength of concrete for single-doped fiber has little effect to improve concrete compressive strength, some even get lower,but mixing-doped coarse-fine fiber had increased 6.2%~13.7%. Doped-fiber can improve the concrete compressive toughness, it's enhancement sort: mixing-doped coarse-fine fiber concrete > single-doped coarse fiber concrete > single-doped fine fiber concrete> plain concrete

Effect of hydrated lime on efflorescence formation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Diogo Henrique de Bem ◽  
Priscila Ongaratto Trentin ◽  
Ronaldo A. Medeiros-Junior
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Design Methodology ◽  
Hydrated Lime ◽  
Content Type ◽  
Mercury Intrusion ◽  
Lime Content ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Historical Heritage

PurposeEfflorescence formation is very common in cement-based materials. In the case of mortar, efflorescence is more studied when only Portland cement is used as a binder. However, the repair of historical heritage, as well as the construction system of some countries, usually uses mortars composed of hydrated lime and Portland cement. This study aims to determine the influence of the hydrated lime content on the incidence of efflorescence in mortars.Design/methodology/approachMortars with 0%, 50%, and 100% lime/cement ratio were studied, using three different methods to accelerate efflorescence formation. The surface area of mortars affected by efflorescence was quantified by analysis using image software. Also, analysis of mercury intrusion porosity test, flexural tensile, compressive strength, absorption of water by capillarity, porosity, XRD and TGA was performed.FindingsMore efflorescence in mortars with a higher amount of lime in their composition was observed. The results show that the increase in the lime content reduces the flexural tensile and the compressive strength and increased the absorption of water by capillarity and the porosity of the mortars. The material formed by the efflorescence was calcium carbonate, proven by microstructural tests.Originality/valueThe results of greater efflorescence formation in mortars with lime are important to alert users who apply this type of material. Some type of protection must be done more rigorously for lime-cement mortars, especially concerning contact with water, since efflorescence tends to be faster for this type of material.

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