scholarly journals Pull Off test to evaluate the compressive strength of concrete: an alternative to Brazilian standard techniques

2012 ◽  
Vol 5 (6) ◽  
pp. 757-780 ◽  
Author(s):  
E. Pereira ◽  
M. H. F. de Medeiros
Keyword(s):  
Compressive Strength ◽  
The United States ◽  
Ultrasonic Test ◽  
Test Results ◽  
Compressive Test ◽  
Rebound Hammer ◽  
Compressive Strength Of Concrete ◽  
Complementary Techniques ◽  
Brazilian Standard ◽  
Standard Techniques

To estimate the compressive strength of concrete is necessary in many reinforced concrete structures inspection works. In Brazil, the standard tests for this purpose are: Compressive test in drilled cores, rebound hammer test and ultrasonic test. In the United States and Europe are also regulated other techniques. The aim of this paper is to analyze the use of Pull Off test as an inspection tool of concrete and also disclose the possibility of use of complementary techniques to the standard ones in Brazil. The results show that the Pull Off test results in high correlation (R²> 0.93) with the compressive strength, measured in cylindrical and prismatic specimens. The rebound hammer test did not show satisfactory correlation (R²≅0.6) for the case of cylindrical specimens. The ultrasonic test showed high correlation (R²> 0.98), but behaves differently with the shape changing of the specimens.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

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.

Research on mechanical behavior of L-shaped multi-cell concrete-filled steel tubular stub columns under axial compression

2018 ◽  
Vol 22 (2) ◽  
pp. 427-443 ◽  
Author(s):  
Jiepeng Liu ◽  
Hua Song ◽  
Yuanlong Yang
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Bearing Capacity ◽  
Thickness Ratio ◽  
Steel Plates ◽  
Test Results ◽  
Finite Element Program ◽  
Element Program ◽  
Compressive Strength Of Concrete ◽  
Stub Columns

A total of 11 L-shaped multi-cell concrete-filled steel tubular stub columns were fabricated and researched in axial compression test. The key factors of width-to-thickness ratio D/ t of steel plates in column limb and prism compressive strength of concrete fck were investigated to obtain influence on failure mode, bearing capacity, and ductility of the specimens. The test results show that the constraint effect for concrete provided by multi-cell steel tube cannot be ignored. The ductility decreases with the increase of width-to-thickness ratio D/ t of steel plates in column limb. The bearing capacity increases and the ductility decreases with the increase in prism compressive strength of concrete fck. A finite element program to calculate concentric load–displacement curves of L-shaped multi-cell concrete-filled steel tubular stub columns was proposed and verified by the test results. A parametric analysis with the finite element program was carried out to study the influence of the steel ratio α, steel yield strength fy, prism compressive strength of concrete fck, and width-to-thickness ratio D/ t of steel plates in column limb on the stiffness, bearing capacity and ductility. Furthermore, the design method of bearing capacity was determined based on mainstream concrete-filled steel tubular codes.

Drying Shrinkage of Concrete Affected by Content of Stone Powder in Proto-Machine-Made Sand

2010 ◽  
Vol 152-153 ◽  
pp. 1176-1179 ◽  
Author(s):  
Feng Lan Li ◽  
Qian Zhu
Keyword(s):  
Compressive Strength ◽  
Standard Method ◽  
Structural Engineering ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Test Results ◽  
Similar Test ◽  
Mix Proportion ◽  
Compressive Strength Of Concrete ◽  
Main Factor

To improve the application of the new proto-machine-made sand in structural engineering, tests are carried out to study the drying shrinkage of concrete affected by stone powder in proto- machine-made sand. The target cubic compressive strength of concrete is 55 MPa, the main factor varied in mix proportion of concrete is the contents of stone powder by mass of proto-machine-made sand from 3 % to 16 %. The drying shrinkage strains of concrete are measured by the standard method at the ages of 1 d, 3 d, 7 d, 14 d, 28 d, 60 d, 90 d, 120 d, 150 d and 180 d. Based on test results, the drying shrinkage of concrete affected by the contents of stone powder in proto-machine-made sand is analyzed and compared with that of similar test of concrete with traditional machine-made sand, which shows that there is the optimum content of stone powder resulting in the lower drying shrinkage of concrete. The formula for predicting drying shrinkage strain of concrete is proposed.

Determination of a Suitable Moment for Formwork Removal from a Concrete Structure Using Rebound Hammer Test Methods

2021 ◽  
Vol 322 ◽  
pp. 23-27
Author(s):  
Petr Misák ◽  
Dalibor Kocáb ◽  
Petr Cikrle
Keyword(s):  
Compressive Strength ◽  
Characteristic Curve ◽  
Test Methods ◽  
Rebound Hammer ◽  
Practical Applications ◽  
Relevant Topic ◽  
Compressive Strength Of Concrete ◽  
The Moment ◽  
Non Destructive

Determining the compressive strength of concrete in the early stages of ageing has been an increasingly relevant topic in recent years, particularly with regard to the safe removal of formwork from a structure or its part. The compressive strength of concrete which designates safe removal of formwork without damaging the structure can be referred to as "stripping strength". It is undoubtedly beneficial to be able to determine the moment of safe formwork removal in a non-destructive manner, i.e. without compromising the structure. Modern rebound hammer test methods seem to be a suitable instrument with which it is possible to reduce the length of technological breaks associated with concrete ageing to a minimum, and consequently, reduce the total cost of the construction. However, the use of these methods presents a number of challenges. As many conducted experiments have shown, there is no single conversion relationship (regression model) between non-destructive rebound hammer test methods and compressive strength. It is therefore advisable to always create a unique conversion relationship for each individual concrete. In addition, it must be noted that conventional regression analysis methods operate with 50% reliability. In construction testing, however, the most common is the so-called characteristic value, which is defined as a 5% quantile. This value is therefore determined with 95% reliability. This paper describes the construction of a so-called "characteristic curve", which can be used to estimate the compressive strength of concrete in a structure using rebound hammer test methods with 95% reliability. Consequently, the values obtained from the characteristic curve can be easily used for practical applications.

scholarly journals Effect of basalt aggregates and plasticizer on the compressive strength of concrete

2015 ◽  
Vol 4 (4) ◽  
pp. 520 ◽  
Author(s):  
Mohammad Al-Rawashdeh ◽  
Ashraf Shaqadan
Keyword(s):  
Compressive Strength ◽  
Laboratory Investigation ◽  
Concrete Strength ◽  
Experimental Program ◽  
Sieve Analysis ◽  
Curing Time ◽  
Compressive Test ◽  
Slump Test ◽  
Compressive Strength Of Concrete

The purpose of this research is to investigate the feasibility of using basalt aggregates and plasticizers in concrete mixes. An elaborate experimental program that included a variation of plasticizer and basalt in concrete mixes. The laboratory investigation included measurements of sieve analysis, compressive strength, and slump test. The compressive test was evaluated at 7, 14, 28 days of curing time. The results show significant improvement in concrete strength up to 2% of additive plasticizer after that concrete strength was reduced.

scholarly journals THE EFFECT OF ADDING CEMENT WASTE ON THE QUALITY OF CONCRETE COMPRESSIVE

Jurnal CIVILA ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 213
Author(s):  
Asrul Majid ◽  
Hammam Rofiqi Agustapraja
Keyword(s):  
Compressive Strength ◽  
Strength Test ◽  
Fine Aggregate ◽  
Infrastructure Development ◽  
Test Results ◽  
Compressive Strength Test ◽  
Compressive Strength Of Concrete ◽  
Concrete Materials ◽  
Test Objects

Infrastructure development is one of the important aspects of the progress of a country where most of the constituents of infrastructure are concrete. The most important constituent of concrete is cement because its function is to bind other concrete materials so that it can form a hard mass. The large number of developments using cement as a building material will leave quite a lot of cement bags.In this study, the authors conducted research on the effect of adding cement waste to the compressive strength of concrete. This study used an experimental method with a total of 24 test objects. The test object is in the form of a concrete cylinder with a diameter of 15 cm and a height of 30 cm and uses variations in the composition of the addition of cement waste cement as a substitute for fine aggregate, namely 0%, 2%, 4% and 6%. K200). The compressive strength test was carried out at the age of 7 days and 28 days.The test results show that the use of waste as a partial substitute for fine aggregate results in a decrease in the compressive strength of each mixture. at the age of 7 days the variation of 2% is 16.84 MPa, 4% is 11.32 MPa and for a mixture of 6% is 6.68 MPa. Meanwhile, the compressive strength test value of 28 days old concrete in each mixture decreased by ± 6 MPa. So the conclusion is cement cement waste cannot be used as a substitute for fine aggregate in fc 16.6 (K200) quality concrete because the value is lower than the specified minimum of 16.6 MPa.

scholarly journals The Effect of the Presence of Ferric Iron in Water used for the Production of Concrete on Its Compressive Strength

2019 ◽  
Vol 4 (8) ◽  
pp. 95-98
Author(s):  
A. T. John ◽  
Solomon Teminusi Orumu ◽  
T. A. Nelson
Keyword(s):  
Compressive Strength ◽  
Water Samples ◽  
Niger Delta ◽  
Ferric Iron ◽  
Local Area ◽  
Test Results ◽  
Raw Water ◽  
University Campus ◽  
Compressive Strength Of Concrete ◽  
Mixing Water

This study examined the effect of ferric iron inherent in mixing water on the compressive strength of concrete. Portland Limestone Cement was considered in the production of the 150mm concrete cube samples. Dirt free river sand and crushed stone with maximum size of 14mm was used as fine and coarse aggregate respectively. The water samples used for the study were sourced from the following locations as stated: Sample 1: Niger Delta University Portable water at Niger Delta University Campus, Wilberforce Island (labelled P1). Sample2: Raw water from borehole at Niger Delta University Campus, Wilberforce Island and allowed to oxidized about 3 hours. Sample 3: Raw water from borehole at Amassoma in southern Ijaw Local Area, Bayelsa state and allowed to oxidized for about 3 hours. Sample 4: Oxidized water from Ogobiri in Sagbama Local Area, Bayelsa state. Sample 5: Oxidized water from Azikoro in Yenagoa Local Area, Bayelsa state. 150mm x 150mm concrete cubes samples were prepared with the various water samples stated above. A mix ratio of 1:11/2:3 was used for this experimental study. The samples were cured in accordance with BS EN 12390-2. Compressive strength values were determined for all specimens by means of a compression testing machine.  Samples were tested to failure at 7, 14, 21 and 28days. The concrete compressive strengths test results for 7, 14, 21, and 28 days for sample 1 was 24.22 N/mm2, 27.63 N/mm2, 34.04 N/mm2 and 34.59N/mm2.  For sample 2 was 18.79 N/mm2, 23.55 N/mm2, 27.30 N/mm2 and 28.59N/mm2, for sample 3 was 21.12 N/mm2, 22.81 N/mm2, 25.19 N/mm2 and 26.56N/mm2, for sample 4 was 19.80N/mm2, 22.71N/mm2, 26.80N/mm2 and 27.40N/mm2and for sample was 20.89N/mm2, 21.88 N/mm2, 26.20 N/mm2 and 27.30N/mm2respectively. The test results, show a noticeable decrease in compressive strength of concrete cubes cast with water that contained ferric iron when compared with water free from ferric iron. It was concluded that Ferric iron as impurities in mixing water have significant effect on the strength of concrete.

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.

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