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.

scholarly journals Correlation between Uniaxial Compression Test and Ultrasonic Pulse Rate in Cement with Different Pozzolanic Additions

2021 ◽  
Vol 11 (9) ◽  
pp. 3747
Author(s):  
Leticia Presa ◽  
Jorge L. Costafreda ◽  
Domingo Alfonso Martín
Keyword(s):  
Compression Test ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Uniaxial Compression Test ◽  
Unconfined Compression Test ◽  
Pozzolanic Cement ◽  
The Relationship ◽  
Compression Resistance

This work aims to study the relationship between the compression resistance and velocity from ultrasonic pulses in samples of mortars with 25% of pozzolanic content. Pozzolanic cement is a low-priced sustainable material that can reduce costs and CO2 emissions that are produced in the manufacturing of cement from the calcination of calcium carbonate. Using ultrasonic pulse velocity (UPV) to estimate the compressive resistance of mortars with pozzolanic content reduces costs when evaluating the quality of structures built with this material since it is not required to perform an unconfined compression test. The objective of this study is to establish a correlation in order to estimate the compression resistance of this material from its ultrasonic pulse velocity. For this purpose, we studied a total of 16 cement samples, including those with additions of pozzolanic content with different compositions and a sample without any additions. The results obtained show the mentioned correlation, which establishes a basis for research with a higher number of samples to ascertain if it holds true at greater curing ages.

Estimation of Compressive Strength of Recycled Aggregate High Strength Concrete Using Ultrasonic Pulse Velocity

2014 ◽  
Vol 605 ◽  
pp. 147-150
Author(s):  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
Yong Taeg Lee
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66

scholarly journals Utilization of Metakaolin and Calcite: Working Reversely in Workability Aspect—As Mineral Admixture in Self-Compacting Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fatih Özcan ◽  
Halil Kaymak
Keyword(s):  
Compressive Strength ◽  
High Strength ◽  
High Volume ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Admixture ◽  
Self Compacting Concrete ◽  
Binder Ratio

In this work, utilization of metakaolin (MK) and calcite (C), working reversely in workability aspect, as mineral admixture in self-compacting concrete (SCC), was investigated. MK and C replaced cement in mass basis at various replacement ratios, separately and together. In total, 19 different SCCs were produced. Binder content and water to binder ratio were selected as 500 kg/m3 and 0.4, respectively. Workability tests including slump flow, T50, L-box, and V-funnel tests were performed. Consistency and setting times of binder paste were measured. While replacement of MK with cement increased the amount of plasticiser requirement, calcite worked reversely and decreased it. Reverse influence of MK and C on plasticiser requirement of SCC made possible to produce SCC at total 45% replacement ratio of MK and C together. Samples of SCC were cured in water at 20°C temperature. Compressive strengths of SCC samples were measured up to six months to evaluate the influence of MK and C, separately and together. Ultrasonic pulse velocity, abrasion, and capillary water absorption values of samples were determined at specified age. MK inclusion in concrete reduces workability, while C inclusion increases it. C and MK inclusion together remedied workability of concrete and enabled to produce SCC with high volume of admixtures. Furthermore, C incorporation increased one-day compressive strength, while MK incorporation reduced it in comparison with control concrete. In long term, C inclusion reduced compressive strength; however, MK inclusion increased it. C inclusion remedied one-day strength of concrete when it was used together with MK. MK inclusion remedied long-term compressive strength when it was used together with C and enabled to produce high-strength SCC with high volume of admixtures. SCC containing MK and C together showed better durability-related property.

scholarly journals Evaluating Concrete Quality using Nondestructive In-situ Testing Methods

2019 ◽  
pp. 22-40
Author(s):  
Khalid Abdel Naser Abdel Rahim
Keyword(s):  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Initial Surface ◽  
In Situ Testing ◽  
Surface Absorption ◽  
Concrete Quality

This manuscript investigate the quality of concrete using non-destructive in-situ testing.The in-situ testing is a process by which different test are carried out such as rebound hammer, ultrasonic pulse veloc-ity, initial surface absorption test and fig air, to determine thein-situ strength, durability and deterioration, air permeability, concrete quality control andperformance. Additionally, the quality of concrete was researched using test methods with experimental results. Moreover, this research has found that (1) the increase in w/c ra-tioleads to a decrease in compressive strength and ultrasonic pulse velocity. Thus, lower w/cratio gives a bet-ter concrete strength in terms of quality, (2) the quicker the ultrasonic pulse travels through concrete indicates that the concrete is denser, therefore, better quality, (3) the lower initial surface absorption value indicates a better concrete with respect to porosity and (4) the w/c ratio plays an important role in the strength and per-meability of concrete.

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.

Estimation of Compressive Strength of Concrete Member Using Ultrasonic Pulse Velocity Method

2014 ◽  
Vol 605 ◽  
pp. 143-146
Author(s):  
Yong Taeg Lee ◽  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
J.H. Park
Keyword(s):  
Compressive Strength ◽  
Wave Velocity ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Concrete Member ◽  
Strength Concrete ◽  
Estimation Formula ◽  
Normal Strength

This study uses the ultrasonic pulse velocity method, one of the non-destructive testing methods that do not damage the structure, to analyze the correlation of wave velocity and compressive strength of normal strength and high strength concrete to propose an estimation formula. And a concrete member is produced to estimate the compressive strength, and provide elementary data for establishing a site-applicable standard for strength estimation formula. In order to analyze the correlation of concrete compressive strength and wave velocity, total of 144 specimens were produced per age, and six concrete members were produced for wave velocity measurement. In this study, the Ultrasonic Pulse Velocity method was used to propose a compressive strength estimation formula of normal strength and high strength concrete, which was applied to concrete members for verification, and the following conclusion was obtained. The correlation between wave velocity and compressive strength was found to be Fc=0.0952VP3.5, R2=0.82 for normal strength concrete, and Fc=0.0028VP6.1, R2=0.83 for high strength concrete. Result of comparing the estimated strength of the concrete member of the relative error rate was standard strength 18.7% on average, the high-strength 8.7%

scholarly journals Effect of Improper Curing on the Properties of Normal Strength Concrete

2018 ◽  
Vol 8 (6) ◽  
pp. 3536-3540
Author(s):  
R. P. Memon ◽  
A. R. M. Sam ◽  
A. Z. Awang ◽  
U. I. Memon
Keyword(s):  
Cement Content ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Controlled Environment ◽  
Normal Strength Concrete ◽  
Normal Concrete ◽  
Normal Strength

In real applications, 28 days are regarded as proper curing time for concrete. There is a self-evident need to minimize the duration of curing days. For this purpose, this research investigates 1 to 7 days of curing and compares it with concrete cured for 28 days. Three grades of normal concrete strength grade 30, grade 35 and grade 40 were made. After curing, two exposure conditions were applied to the concrete, inside laboratory-controlled environment and outside environment. Results indicate that slump increases with cement content in DOE method at constant water content. The concrete density in all grades reduces when the concrete is subject to inside exposure in comparison with outside exposure. Water loss from concrete reduces with increase in curing days in all concrete grades. Compression strength of all concrete grades increases with increase in curing days. For the uniformity of concrete, ultrasonic pulse velocity indicated that with an increase in curing days, concrete becomes denser and a bit void. Results showed that an increase in curing days also improves the surface quality of concrete. The significance point noticed is that there was not much difference in the concrete properties between 7 days of curing and 28 days of curing in all grades.

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