scholarly journals Changes in the Compressive Strength of Concrete in Thin Horizontally Formed Slabs

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5671
Author(s):  
Jacek Szpetulski ◽  
Bohdan Stawiski
Keyword(s):  
Compressive Strength ◽  
Horizontal Position ◽  
Test Results ◽  
Entire Thickness ◽  
Formed Element ◽  
Test Elements ◽  
Water Move ◽  
Compressive Strength Of Concrete ◽  
Light Components ◽  
Concrete Elements

During compaction of a concrete mix, when thin slabs are formed in a horizontal position, the components of this mix become segregated. Heavy components fall to the bottom, and light components (air and water) move to the top. This process may suggest that the upper layers of concrete elements formed in a horizontal position may have lower compressive strength than the remaining part of the element. This problem is recognized and documented in many publications, but there was a publication whose test results indicate a lack of variability in the compressive strength of concrete across the thickness of tested elements. The discrepancies appearing in the evaluation of concrete homogeneity was the reason for conducting destructive tests of the compressive strength of concrete across the thickness of horizontally concreted test elements that imitate thin slabs. The obtained results of the destructive compressive strength confirmed previous results regarding the heterogeneity of concrete. They clearly indicate that there is a differentiation of the compressive strength of concrete across the thickness of a thin element, which remained in a liquefied state for a certain time during its formation. The longer the duration of this state across the entire thickness of the formed element, the greater the differentiation of the compressive strength between the top and bottom layers.

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.

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 ABOUT THE CALCULATION OF CONCRETE ELEMENTS SUBJECTED TO LOCAL COMPRESSION

2005 ◽  
Vol 11 (3) ◽  
pp. 243-248
Author(s):  
Vytautas Venckevičius
Keyword(s):  
Compressive Strength ◽  
Cross Section ◽  
Normal Weight ◽  
Steel Plates ◽  
Theoretical Research ◽  
Engineering Structures ◽  
Normal Weight Concrete ◽  
Concentration Problem ◽  
Compressive Strength Of Concrete ◽  
Concrete Elements

The problem of calculating the local compressive strength of normal‐weight concrete elements of building and engineering structures locally loaded by rigid steel plates on a small area surrounded from all sides by a non‐loaded larger area of cross‐section is presented in this paper. The results of experimental and theoretical investigations show that this stress‐strain concentration problem is rather complicated. Therefore up to now for the determination of local compressive strength of concrete elements various calculation methods have been used. The author of this paper proposed an alternative method the algorithm of which is based on the results of statistical analysis of numerous experimental data, conclusions of adequate theoretical research and propositions of SNiP, Eurocode2 and other design codes. According to this calculation method, the design local compressive strength of concrete and concrete elements depends not only on magnitude of local load concentration but also on characteristics of mechanical properties of concrete ‐axial tensile and compressive strength and relative element height (ratio of element height with less line of its cross‐section) too. The results of comparative calculations showed that experimental research data better comply with the calculated ones by the proposed method than with the obtained ones by SNiP, SNB, STR and Eurocode2 methods.

scholarly journals PENGARUH VARIASI DIAMETER MAKSIMUM AGREGAT DALAM CAMPURAN TERHADAP KEKUATAN TEKAN BETON

2019 ◽  
Vol 3 (1) ◽  
pp. 11-23
Author(s):  
Helwiyah Zain
Keyword(s):  
Compressive Strength ◽  
Maximum Diameter ◽  
Concrete Aggregate ◽  
Test Results ◽  
Natural Mineral ◽  
Size Selection ◽  
Concrete Mix ◽  
Compressive Strength Of Concrete ◽  
Average Compressive Strength

Aggregate is a natural mineral grains that serve as filler in concrete mix, and the greatest material contained in the concrete. These material influence on the properties of concrete, so that the diameter size selection is essential in making the concrete. This study aims to determine the effect of variations of aggregate maximum diameter to the compressive strength of concrete. In this study used 15 specimens, were divided into 3 groups witch each of 5 specimens. Each group is distinguished aggregate maximum diameter: 31.5 mm, 16 mm, and 8 mm. Specimens used in this study is the specimen cylinder with a diameter of 15 cm and 30 cm high. Speciment tested done at age of concrete 28 days. The average compressive strength of concrete for each group of test based on variations of  the aggregate maximum diameter is: for the aggregate maximum diameter of 31.5 mm = 249.67 kg / cm2; the aggregate maximum diameter 16 mm = 274.91 kg / cm2; and the aggregate maximum diameter of 8 mm = 326.74 kg / cm2. Based on these test results, show that the average compressive strength of the concrete for the aggregate maximum diameter of 16 mm is 10.11% stronger than the concrete with the aggregate maximum diameter of 31.5 mm; and the strength of concrete aggregate maximum diameter of 8 mm, 30.87% stronger than the concrete with aggregate maximum diameter of 31.5 mm.

scholarly journals Effect of R.O. Waste Water on Properties of Concrete

2019 ◽  
Vol 8 (3) ◽  
pp. 2806-2808
Keyword(s):  
Waste Water ◽  
Compressive Strength ◽  
Reverse Osmosis ◽  
Potable Water ◽  
Fresh Concrete ◽  
Test Results ◽  
Normal Concrete ◽  
Experimental Procedure ◽  
Compressive Strength Of Concrete

This paper concentrates on preparing concrete in which reverse osmosis waste water is incorporated in mixing and to cure. Experimental procedure consists of 4 mix proportions of various water cement ratios. Fresh concrete is tested for workability and flowing ability. Cubes were casted and tested to find out compressive strength of concrete. Test results of potable water concrete and RO waste water concrete were compared. Results show that workability of both the concretes is almost same. When coming to the compressive strength, RO waste water concrete shows less strength at 28days compared to normal concrete.

scholarly journals STRENGTH DEVELOPMENT OF CONCRETE WITH FLY ASH ADDITION

2007 ◽  
Vol 13 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Marta Kosior-Kazberuk ◽  
Małgorzata Lelusz
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mathematical Models ◽  
Statistical Methods ◽  
Experimental Results ◽  
Strength Development ◽  
Hardened Concrete ◽  
Test Results ◽  
Different Types ◽  
Compressive Strength Of Concrete

Based on experimental results, mathematical models were elaborated to predict the development of compressive strength of concrete with fly ash replacement percentages up to 30 %. Strength of concrete with different types of cement (CEM I 42.5, CEM I 32.5, CEM III 32.5), after 2, 28, 90, 180 days of curing, have been analysed to evaluate the effect of addition content, the time of curing and the type of cement on the compressive strength changes. The adequacy of equations obtained was verified using statistical methods. The test results of selected properties of binders and hardened concrete with fly ash are also included. The analysis showed that concrete with fly ash is characterised by advantageous applicable qualities.

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