Influence of Testing Variables on the Concrete Compressive Strength

1975 ◽  
Vol 2 (4) ◽  
pp. 606-611
Author(s):  
T. Dale Rokosh ◽  
K. W. Nasser
Keyword(s):  
Compressive Strength ◽  
Compression Test ◽  
Minor Effect ◽  
Concrete Compressive Strength ◽  
Testing Laboratories ◽  
Concrete Mix ◽  
Commercial Testing ◽  
The Mean ◽  
A Minor ◽  
Good Rating

This study assessed the significance of testing variables due to casting, curing, and breaking standard concrete compression test cylinders in three Saskatoon, Saskatchewan commercial testing laboratories. Analysis of the results indicated that these variables have a minor effect on the results when the laboratories have a 'good' rating. Nonuniformity of the concrete mix itself seemed to have the greatest influence on the within-test variation and caused the mean compressive strength in each laboratory to differ by ±4% of the overall mean strength of the mix.

scholarly journals Influences of shrinkage reducing admixture on the mechanical properties, drying shrinkage, water absorption and porosity of Portland cement mortar

2021 ◽  
Vol 15 (3) ◽  
pp. 55-67
Author(s):  
Nguyen Van Chinh
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Effective Porosity ◽  
Minor Effect ◽  
Wide Range ◽  
Shrinkage Reducing Admixture ◽  
A Minor

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.

Removal of organics from wastewater using a novel biological hybrid system

2001 ◽  
Vol 43 (1) ◽  
pp. 321-326 ◽  
Author(s):  
H. A. Al-Sharekh ◽  
M. F. Hamoda
Keyword(s):  
Activated Sludge ◽  
Hybrid System ◽  
Treatment Plant ◽  
Minor Effect ◽  
Loading Rates ◽  
Innovative System ◽  
The Mean ◽  
Percentage Removal ◽  
Removal Efficiencies ◽  
A Minor

This paper summarizes the results obtained using the hybrid aerated submerged fixed-film (HASFF) process. HASFF is an innovative system comprising a four-compartment reactor having an array of fixed ceramic plates maintained under diffused aeration to support attached biomass, with activated sludge recycle to promote suspended growth in the reactor. Wastewater from a municipal treatment plant was fed to the reactor and its activated sludge was used for recycling in the hybrid system. Four pilot units were operated in the plant at various hydraulic retention times, HRTs (2, 4, 6 and 8 h), using primary-settled wastewater under organic loading rates up to 0.7 g BOD/gMLTVS · d. Data obtained showed that the overall BOD percentage removal efficiencies were consistently above 94.0% at all HRTs including the 2 hours while the COD percentage removal efficiencies ranged between 65.7–76%. The effluent's mean filtered BOD concentration ranged between 4.5–7.5 mg/l whereas the mean filtered COD concentration ranged between 70.0–89.6 mg/l. Increasing the hydraulic loading rate by four-folds from 0.08 to 0.32 m3/m2 · d had a minor effect on the unit's BOD and COD percentage removal efficiencies indicating a robust biological process that is resilient to hydraulic shock loads, thereby offering a viable upgrading option.

scholarly journals Effects of Disparate Zones of Sand on the Compressive Strength of Concrete

2021 ◽  
Vol 9 (11) ◽  
pp. 1368-1375
Author(s):  
Suhaib Bakshi
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Testing Machine ◽  
Concrete Compressive Strength ◽  
Research Papers ◽  
Concrete Material ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Concrete Mix ◽  
Compressive Strength Of Concrete

Abstract: Compressive strength of concrete is the capacity of concrete to bear loads of materials or structure sans breaking or being deformed. Specimen under compression shrinks in size whilst under tension the size elongates. Compressive strength essentially gives concept about the properties of concrete. Compressive strength relies on many aspects such as water-cement ratio, strength of cement, calidad of concrete material. Specimens are tested by compression testing machine after the span of 7 or 28 days of curing. Compressive strength of the concrete is designated by the load on the area of specimen. In this research various proportions of such aggregate mixed in preparing M 30 grade and M 40 grade of Concrete mix and the effect is studied on its compressive strength . Several research papers have been assessed to analyze the compressive strength of concrete and the effect of different zones of sand on compressive strength are discussed in this paper. Keywords: Sand, Gradation, Coarse aggregate, Compressive strength

scholarly journals PEMANFAATAN LIMBAH CANGKANG KERANG HIJAU DENGAN VARIASI SUHU PEMBAKARAN SEBAGAI BAHAN PENGGANTI SEBAGIAN SEMEN PADA PEMBUATAN BETON

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Julia Widia Nika ◽  
Anisah Anisah ◽  
Rosmawita Saleh
Keyword(s):  
Compressive Strength ◽  
Chemical Substance ◽  
Mix Design ◽  
Partial Replacement ◽  
Concrete Compressive Strength ◽  
Mussel Shell ◽  
Concrete Mix Design ◽  
Concrete Mix ◽  
Shell Waste ◽  
And Control

This research aims to utilize green mussel shell waste as a partial replacement for cement by establishing the best temperature that should be used to obtain the chemical substance if the sehell ashes to optimize the chemical substance for replacement of cement. This research replaces 10% of total weight cement with shell ash which has been combusted with a temperature of 700 ° C, 800 ° C and 900 ° C and control concrete. The compressive strength of the concrete plan is 20 MPa. Concrete mix design is 1:2:3. The results of this study indicate with subtitutes 10% semen with green shell ash with temperature 700 ° C, 800 ° C and 900 ° C is 20,53MPa; 16,76 MPa and 19,74 MPa and for control concrete has compressive strength 20,18 MPa. The maximum concrete compressive strength was obtained on the concrete of green shell ash with a combustion temperature of 700 ° C which is 20.53 MPa. In the concrete the green shells ash with a burning temperature above 700 ° C experience a decrease in compressive strength and cannot meet the compressive strength of the plan.

An ERAFNN Prediction of Concrete Compressive Strength Based on Physical Properties of Electric Arc Furnace Oxidizing Slag

2014 ◽  
Vol 627 ◽  
pp. 111-114
Author(s):  
Li Chen ◽  
Tzu Yi Pai
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Percentage Error ◽  
Arc Furnace ◽  
Concrete Compressive Strength ◽  
Predicting Performance ◽  
Strength Based ◽  
The Mean

In this study, exact radial basis function neural network (ERBFNN) was used to predict the concrete compressive strength based on physical properties of electric arc furnace oxidizing slag. The mean absolute percentage error (MAPE) was used to evaluate the predicting performance. The results indicated the minimum MAPE of 0.08 % and 5.28 % could be achieved when training and predicting, respectively. According to the results, it revealed that ERBFNN was an efficiently tool for providing information.

Aggregate-Based Modulus of Elasticity for Florida Concrete

2005 ◽  
Vol 1914 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Nur Yazdani ◽  
Bryant McKinnie ◽  
Saif Haroon
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Unit Weight ◽  
Structural Members ◽  
Department Of Transportation ◽  
Regression Analyses ◽  
Concrete Compressive Strength ◽  
Florida Department ◽  
Concrete Mix ◽  
Best Fit

The current empirical model for the Florida Department of Transportation (FDOT) concrete modulus of elasticity (E) is a function of concrete compressive strength and unit weight. Recent testing shows that this model consistently underestimates E for FDOT concrete. This underestimation may lead to construction problems caused by the overprediction of camber and the deflection of concrete structural members. E values for the typical concrete mix used in FDOT projects were experimentally determined at various concrete ages. Regression analyses were used to find the E models that best fit the generated data, and such models were compared with existing E models from the literature. It was found that the aggregate type and specific gravity play significant roles in influencing the E value of concrete. The best-fit E models for FDOT concrete, together with suggested modification factors for various aggregate types, are recommended.

scholarly journals TINJAUAN KUAT TEKAN BETON DENGAN MENGGUNAKAN SERAT BENDRAT SEBAGAI BAHAN TAMBAH

2019 ◽  
Vol 1 (2) ◽  
pp. 124-132
Author(s):  
Hermansyah ◽  
Moh Ihsan Sibgotuloh
Keyword(s):  
Compressive Strength ◽  
Fresh Concrete ◽  
Mix Design ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Fiber Concrete ◽  
Concrete Mix ◽  
Materials Used ◽  
Average Compressive Strength

The more widespread use of concrete construction and the increasing scale of construction, the higher the demand for materials used in concrete mixes. One of the innovations of concrete is fiber concrete. Hope the addition of fiber in concrete mixes such as wire fiber to increase the compressive strength value of normal concrete that is often used, so the purpose of this study is to determine the effect of adding wire fiber to the ease of working (workability) of the concrete mixture and to determine the effect of adding wire fiber to concrete compressive strength. In this study, the fiber used is the type of wire fiber with a diameter of 1 mm and a length of 60 mm. Fiber variations used are 0%, 0.4%, 0.6% and 0.8% based on the weight of fresh concrete. Concrete mix (mix design) using SNI 03-2834-2000 about concrete mix planning with a test life of 28 days. The test results showed that the lowest average compressive strength of 12,291 MPa occurred at 0% variation and the highest average compressive strength value of 20,656 MPa at 0.8% fiber variation. The increase is caused by the even distribution of fibers in the concrete produced, the higher the variation that is given by the fiber, the better the fiber spread, from these fibers provide a fairly good contribution to the fiber concrete

scholarly journals Influence of Different Nano Materials on Mechanical Properties of Plain Concrete

2019 ◽  
Vol 4 (6) ◽  
pp. 129-134
Author(s):  
Mohamad Farouk Abd-elmagied
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Iron Oxide ◽  
Cement Content ◽  
Plain Concrete ◽  
Nano Materials ◽  
Nano Silica ◽  
Concrete Compressive Strength ◽  
Concrete Mix ◽  
Different Types

This research aims to study the influences of three types of Nano materials on concrete compressive strength, considered Nano types were Nano-Iron Oxide Fe2O3 (NF), Nano-Manganese Oxide Mn2O3 (NM), and Nano-Silica SiO2 (NS). A constant concrete mix and water content were considered. The used percentages of different types of (NF, NM, and NS) that replaced by the cement content were (0.5, 1.0, 2.0, and 5.0%) of mixture weight (wt). The results demonstrated that the (NS) Nano type has better effect than other types on the concrete compressive strength.

scholarly journals Concrete Compressive Strength under Changing Environmental Conditions during Placement Processes

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4577 ◽  
Author(s):  
Andrzej Ambroziak ◽  
Patryk Ziolkowski
Keyword(s):  
Compressive Strength ◽  
Technological Process ◽  
Daily Temperature ◽  
Hardened Concrete ◽  
Concrete Compressive Strength ◽  
Concrete Mix Design ◽  
Temperature And Precipitation ◽  
Concrete Production ◽  
Concrete Mix ◽  
Limiting Behaviour

The technological process of concrete production consists of several parts, including concrete mix design, concrete mix production, transportation of fresh concrete mix to a construction site, placement in concrete framework, and curing. Proper execution of these steps provides good quality concrete. Some factors can disturb the technological process, mainly temperature and excessive precipitation. Changing daily temperature and rainfall during fabrication, transportation, and placement can shape not only the properties of the concrete mix but also the compressive strength of hardened concrete. In this paper, we tried to answer the question of how temperature and precipitation affect concrete production. The scope of this study was to determine the change of compressive strength of the hardened concrete in a specific period for selected concrete mix recipes, taking into account changing daily temperature and precipitation magnitude. The investigated concrete mixes concrete compressive strength beyond that of the concrete grade, termed “concrete superstrength”. This concrete post limiting behaviour of concrete is also discussed.

The Effect of Eggshells Ash on the Compressive Strength of Concrete

2017 ◽  
Vol 728 ◽  
pp. 402-407 ◽  
Author(s):  
Fazeera Ujin ◽  
Kamran Shavarebi Ali ◽  
Zarina Yasmin Hanur Harith
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compression Test ◽  
Conventional Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Cement Replacement ◽  
Concrete Mix ◽  
Compressive Strength Of Concrete ◽  
Landfill Disposal

This paper presents the main results of the research carried out to analyse the mechanical properties of concrete incorporating with eggshells waste. The use of eggshells ash in concrete formulations was investigated as an alternative to landfill disposal. The objective of this study is to find the suitability of eggshells ash as cement replacement in concrete. The cement has been replaced by waste eggshells ash accordingly in the range of1% and 2.5%. The eggshell ash passing the 90μm sieve was used in the investigation. By using 1% and 2.5% amount of the waste eggshells ash, water cement ratio were designed which is 0.47, 0.55 and 0.70 and compared in terms of slump and strength with the conventional concrete. The concrete specimens were tested in the series of compression test to determine the strength of concrete for 3, 7 and 28 days. As a result, the additional of eggshells ash to the concrete mix increase the strength of the concrete. In short, the higher percentage of eggshells ash in the mix means a higher compressive strength for the concrete. Hence, it is suggested that eggshells ash can be used as partially cement replacement in concrete.

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