scholarly journals STUDYING SOME OF THE MECHANICAL AND PHYSICAL PROPERTIES OF COLORED GEOPOLYMER CONCRETE

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-49-2-59
Author(s):  
Mohammed H. Mahmud ◽  
◽  
Mohammed A. Abdulrehman ◽  
Keyword(s):  
Mechanical Characteristics ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Geopolymer Concrete ◽  
Oxide Hydroxide ◽  
Mechanical And Physical Properties ◽  
Rebound Number ◽  
Physical And Mechanical Characteristics

This study has been done to study the physical and mechanical characteristics of colored geopolymer concrete by adding two types of pigments yellow (iron oxide hydroxide) and blue (cobalt) with three additional proportions for each of the listed colors (0,2, 4, 6% wt), some materials which are available in the native market and other materials imported from outside of the country. The experimental investigation has dealt with the fresh properties(slump) of the colored geopolymer concrete mixes as well as some of the mechanical and physical characteristics of the hardened concrete by testing specimens in compressive strength, flexural strength, water absorption, Rebound number (RN), and ultrasonic pulse velocity (UPV). In addition to that, Finding a relationship between the destructive (strength of compressive) and (RN and UPV) tests. Show us that (2% wt) pigment percentage gives the best results.

scholarly journals Using of metakaolin to produce colored geopolymer concrete

2021 ◽  
Vol 2114 (1) ◽  
pp. 012018
Author(s):  
M Mohammed Hameed ◽  
A Mohammed Ali
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Modulus Of Rupture ◽  
Hardened Concrete ◽  
Geopolymer Concrete ◽  
Fresh Properties ◽  
Rebound Number

Abstract This study was related to produce colored geopolymer concrete using metakaolin and adding two types of red (iron oxide) and green (chromium oxide) pigments with three additional ratios for each of the listed colors (0, 2, 4, 6 )% wt of metakaolin, and study some mechanical properties of colored geopolymer concrete. The experimental investigation has dealt with the fresh properties(slump) of the colored geopolymer concrete mixes as well as some of the mechanical properties of the hardened concrete by testing specimens in compressive strength, modulus of rupture, Rebound number (RN), and ultrasonic pulse velocity (UPV). Show us that (2% wt) pigment percentage gives the best results.

scholarly journals High Strength Nano Silica Based Concrete

2020 ◽  
Vol 9 (7) ◽  
pp. 1150-1155
Keyword(s):  
Electron Microscope ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Nano Silica ◽  
Nano Structure ◽  
Transmission Electron

There is a substantial curiosity in academia, the investment community and among manufacturers about the exhilarating opportunities offered by nano materials. Although a lot of applications for nanotechnology remain hypothetical, construction is one area where numerous ‘here and now’ applications have already emerged. While existing use is restricted, the market is likely to approach more than 500 million dollars within ten years. Concrete is most likely exceptional in the construction field, that it is the distinct material exclusive to business and hence, is the recipient of a reasonable quantity of research and development capital from the construction industry. SiO2 (Silica) usually is an integral part of concrete in the normal mix. On the other hand, one of the innovations made by the study of concrete at nano scale level is that particle stuffing in concrete can be enhanced by means of adding nano silica (NS), which results in the densification of the micro and nano structure of cementitious composite resulting in enhanced mechanical properties. In this research paper, the result of a thorough investigational analysis on the utilization of NS in addition to cement so that the strength and quality of concrete can improve has been achieved. The effect of various proportions of NS in concrete has been premeditated to evaluate the properties of NS based hardened concrete according to the standard concrete. The obtained outcomes after testing indicate that the addition of NS together with concrete has improved the mechanical behavior of concrete. The NS blended high strength concrete (HSC) shows a better compressive strength (CS) of 66.00 N/mm2 (MPa) after standard twenty eight days, which is an exceptional development over standard concrete. Each and every mixture containing NS in various proportions gave enhanced outcomes in comparison with the standard predictable concrete. RH (Rebound Hammer), UPV (Ultrasonic Pulse Velocity), SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope) examinations further authenticate the above results.

Non-Destructive Tests as Durability Indicators in Cement Mortars with Pozzolanic Substitutions

2017 ◽  
Vol 902 ◽  
pp. 9-13
Author(s):  
Rosalía Ruiz Ruiz ◽  
Elia Mercedes Alonso Guzmán ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Judith Alejandra Velázquez Perez
Keyword(s):  
Mechanical Characteristics ◽  
Ultrasonic Pulse Velocity ◽  
Good Alternative ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Industry ◽  
Capillary Absorption ◽  
Pozzolanic Material ◽  
Cement Mortars ◽  
Non Destructive

Cement industry is responsible of 5-7% of CO2 emissions to the atmosphere. This is preoccupant because this is one of the greenhouse effect gases which cause global warming. Pozzolanic material incorporation in cement mortars elaboration represents a good alternative to partially substitute cement, since its chemical composition could contribute to improvement of its durability and mechanical characteristics. In this research, mortars with pozzolanic substitutions are evaluated through non-destructive tests as: capillary absorption, electrical resistivity, and ultrasonic pulse velocity to the age of 1000 days. The results suggested that the incorporation of pozzolanic material as partial substitutes of Portland cement increases the mortars properties mainly in substitutions of CBC 20%, PN 10, and 30%.

scholarly journals Empirical Investigation on Compressive Strength of Geopolymer and Conventional Concretes by Nondestructive Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
B. Ravali ◽  
K. Bala Gopi Krishna ◽  
D. Ravi Kanth ◽  
K. J. Brahma Chari ◽  
S. Venkatesa Prabhu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Nondestructive Method ◽  
Geopolymer Concrete ◽  
River Sand ◽  
Rebound Hammer ◽  
Compressive Strength Of Concrete

Need of construction is increasing due to increase in population growth rate. The geopolymer concrete is eco-friendly than ordinary concrete. Current experimental investigation was conducted on ordinary and geopolymer concrete using nondestructive testing (NDT) tests like ultrasonic pulse velocity (UPV) test and rebound hammer (RH) test. Cube specimens of dimensions 150 mm × 150 mm × 150 mm are used to conduct these tests at 7, 14, and 28 days. Proportions considered for concrete are cement-fly ash-river sand (100-0-100% and 60-40-100%), cement-fly ash-robo sand (100-0-100% and 60-40-100%) whereas geopolymer concrete fly ash-metakaolin is taken in proportions of 100-0%, 60-40%, and 50-50%. Alkaline activators (sodium hydroxide and sodium silicate with molarity 12M) were used in preparing geopolymer concrete. The major objective of the current study is to obtain relation between compressive strength of concrete and UPV values.

An Ultrasonic Pulse Velocity Test on Fly-Ash Based Geopolymer Concrete in Frequency Domains

2014 ◽  
Vol 700 ◽  
pp. 310-313 ◽  
Author(s):  
Jee Sang Kim ◽  
Tae Hong Kim
Keyword(s):  
Compressive Strength ◽  
Construction Material ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Peak Frequency ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
P Wave ◽  
Geopolymer Concrete ◽  
Existing Structures

The Non-Destructive Test techniques on concrete, which can assess the properties of materials without damages, have been developed as the deteriorations of existing structures increase. Among them, the ultrasonic pulse velocity (USPV) method is widely used because it can investigate the states of one material for a long time and repeatedly. However, there have been few researches on the NDT application to geopolymer concrete which is environment friendly construction material without any cement. This paper investigates the variations of ultrasonic pulse velocity and peak frequency of geopolymer concrete under monotonically increasing loads to assess the material conditions with various compressive strength levels by measuring P-wave signals. The pulse velocities and peak frequencies were higher in high strength geopolymer concrete specimens. There are not explicit relations between strength levels and peak frequencies but the peak frequencies are strongly influenced by the applied stress levels. In addition, a predicting equation for compressive strength of geopolymer concrete is derived based on experimental data in similar form for normal concrete.

scholarly journals PROPERTIES OF CONCRETE MODIFIED BY AMORPHOUS ALUMINA SILICATE

2015 ◽  
Vol 6 (4) ◽  
pp. 178-183 ◽  
Author(s):  
Džigita Nagrockienė ◽  
Giedrius Girskas ◽  
Gintautas Skripkiūnas ◽  
Aurelijus Daugėla
Keyword(s):  
Compressive Strength ◽  
Tap Water ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Fine Aggregates ◽  
Amorphous Alumina ◽  
Materials Used ◽  
Polycarboxylate Ether

Concrete is the most widely used building material obtained by hardening the mix made of coarse and fine aggregates, cement as the binding material, and water. The basic properties of concrete depend on the quality and properties of cement, w/c ratio and the homogeneity of compaction. Compressive strength is one of the most important properties of concrete. Materials used: Portland cement CEM I 42.5 R, 0/4 fraction sand, 4/16 fraction gravel, amorphous alumina silicate admixture, polycarboxylate ether-based superplasticizer Muraplast FK 63.30, and tap water. Five compositions of concrete mixes containing 0%, 2.5%, 5%, 7.5% and 10% of amorphous alumina silicate admixture by mass of cement were produced. The article analyses the effect of amorphous alumina silicate on the properties of concrete depending on the admixture content. The results revealed that the compressive strength of concrete after 7 days of curing increased by 7.1%, after 28 days of curing increased by 13.3% when the amorphous aluminum oxide doped silicate content was increased to 10%. Amorphous alumina silicate admixture added in quantities of up to 10%, increased the density of hardened concrete by 0.75%, and ultrasonic pulse velocity in specimens with the admixture increased up to 2.63%.

scholarly journals MECHANICAL, THERMAL AND DURABLE PERFORMANCE OF WASTES SAWDUST AS COARSE AGGREGATE REPLACEMENT IN CONVENTIONAL CONCRETE

2018 ◽  
Vol 81 (1) ◽  
Author(s):  
Gassan Fahim Huseien ◽  
Ruhal Pervez Memon ◽  
Ziyad Kubba ◽  
Abdul Rahaman Mohd Sam ◽  
Mohammad Ali Asaad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Elevated Temperatures ◽  
Evaluation Process ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Conventional Concrete ◽  
Long Duration ◽  
Mechanical And Physical Properties

Wood yields a number of by-products and Sawdust is as useful as others. Sawdust is regarded as a waste material and is effectively utilised as sawdust concrete in the construction of buildings. It is capable to be utilised as light-weight concrete and holds the quality of long duration heat transfer. In this study, three different ratios (1:1, 1:2 and 1:3) volume mix proportions of cement to sawdust were adopted to make sawdust concrete. At varied intervals of 7, 28 and 56 days of air curing, thermal and mechanical properties like workability, density, elastic modulus, strength and heat transfer were probed of mentioned sawdust concrete proportions. The resistance to elevated temperatures was also evaluated after 28 days of age; weight loss, residual compressive strength, surface texture and ultrasonic pulse velocity were considered in evaluation process. The findings showed that increase in sawdust volume affected to decrease the workability, strength and elevated temperatures resistance. However, the concrete having higher proportion of sawdust performed competently and well in terms of thermal conductivity. Moreover, a decrease in the heat transfer of sawdust was also observed. Examining the all-embracing mechanical and physical properties, sawdust can be effectively utilised in the construction of buildings.

scholarly journals Eco-Friendly Chopped Tire Rubber as Reinforcements in Fly Ash Geopolymer Concrete

2020 ◽  
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Industrial Wastes ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Tire Rubber ◽  
Naoh Solution

<p>One of the major challenges faced by researchers is to recycle industrial wastes in a manner that reduces their environmental impact in nature. An experimental study was carried out to determine the suitability of using chopped tire rubber as reinforcements in green and sustainable geopolymer concrete, with the purpose of using them as nonstructural products. The geopolymer mixture was made by mixing of fly ash powder, fine aggregate, and Superplasticizer in Na2SiO3/NaOH solution. Mixtures were divided into four different groups, with constant water to fly ash ratio of 0.12 and alkaline dosage of 45% by weight of fly ash, based on the recycled chopped tire rubber (CTR) content: 0, 10, 20, and 30% by volume of fine aggregate with two maximum sizes (2 and 4mm). Hardened properties of resulted geopolymer like compressive strength, density; and ultrasonic pulse velocity were examined at 28d. Besides that, X-Ray diffractometer and Scanning Electron Microscope were used in order to observe the microstructure of the resulted geopolymer concrete. In view of the consequences for this study, it is preferable to replace no more than 10% of fine aggregate in geopolymer concrete by CTR. In addition, according to SEM photographs, increasing the CTR content more voids will be pronounced and thus, decreasing the mechanical performance.</p>

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