Concrete Compressive Strength Values Research Articles

The Effect of Stirring Time and Concrete Compaction on K-200 Concrete Press Strength

Concrete is a component that has an important function for buildings, both in the form of buildings, housing, highways, and other public facilities. The use of concrete, which is getting longer and higher, also has to maintain the quality of the concrete. One of the problems in concrete is the problem of compaction, the existence of cavities in concrete is a problem that if left unchecked will be fatal, concrete that has an automatic cavity will also reduce the value of concrete compressive strength, concrete compaction usually uses a vibrator or vibrator, but in reality the use the vibrator is used in a random way and does not have a fixed time rule, so the concrete is not evenly packed. This study discusses the compressive strength of concrete are produced with a mixture of the same sample but with different rules vibration time s ehingga find the time to achieve the maximum compressive strength of concrete. For the average value of the highest compressive strength produced by concrete withthe duration of Concrete Mix At 30 minutes and vibrator For 5 minutes with strong average value press concrete reaching 202.67 kg / cm2. While the value of the lowest compressive strength is produced byconcrete Durationof Concrete Mix At 30 minutes and vibrator For 10 Minutes above can be seen strong average value press concrete reaching 158.22 kg / cm2

Value of Concrete Compressive Strength on 28 days with Variation of Candlenut Shell Applicated to Plate on a Non-destructive Test Using Hammer Test

Concrete compressive strength is one of the parameters used to control the quality of a concrete. Concrete compressive strength testing method which is considered the highest level of reliability is a destructive test using a compressive testing machine. Testing requires quite high costs and a longer processing time. But sometimes testing must be done in the scene. Based on the case, a testing tool is needed to measure or determine the compressive strength of concrete without spoil, which is known as the non-destructive test. The tool commonly used for this test is the hammer test. The type of research is experimental. The purpose of this research is to get the compressive strength value of a concrete plate variation of 30% candlenut shells from the test results using a hammer test so as the results can be close to the results of testing using a compressive testing machine (destructive test). The research variable is the testing method (3 point of testing with angle 0°), the age of concrete plate curing, the method of curing (wet curing and dry curing). The number of samples of reinforced concrete slabs is 8 pieces measuring 50cm x 25 cm x 12cm. The research results are Compressive strength of concrete slabs of 30% candlenut shell variations using a Hammer test showed that the concrete strength reached 23-27 Mpa both in wet curing and dry curing or equivalent to the quality of K250 concrete at 28 days. The results also indicate higher values compared to normal concrete slabs.

Variation Analysis Addition of Admixture Consol N10 MB to Concrete Compressive Strength

One of the efforts to improve the quality and quantity of concrete produced is by providing added material to the concrete mixture. PT. Kimia Konstruksi Indonesia produces cosol which is chemical construction of high quality, durable, easy to apply and more economical price. Consol has various types of products with different advantages such as Consol N10 MB is an admixture for high strength concrete. The purpose of this study is to determine the value of concrete compressive strength with the addition of material variations admixture to the N10 MB consol. Concrete design refers to the DoE and SNI 03-2493-1991 methods with cylindrical molds measuring 150 mm x 300 mm. Concrete quality of the K-300 plan with the percentage addition of Consol N10 MB, 0%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2% and 1.5% with time testing at the age of 28 days. The test results show that the tendency of the average compressive strength graph has increased with the addition of N10 MB to 0.5%, with the highest average compressive strength obtained at the addition of 0.5% N10 MB consol of 369.48 kg / cm2 and the resulting equation is y = -113.5 x2 + 109.8 x + 327.1

Prediction of concrete compressive strength based on principal component analysis and radial basis function neural network

Aiming at the concrete compressive strength data measured in the field laboratory, the data samples are standardized and the missing and abnormal values of the data samples are detected and processed. Then, the principal component factors of several influencing factors are extracted with the idea of “dimensionality reduction” by principal component analysis, and a new data sample set is established. Finally, the radial basis function neural network model is constructed to simulate the concrete compressive strength. The strength is predicted and the predicted value is obtained. The results show that three principal component influencing factors are extracted by principal component analysis, and the RBF network structure with 50 neuron nodes in the hidden layer is established. The error of the predicted value of concrete compressive strength is less than 4%, which meets the control requirements of engineering test accuracy. The predicted model can be used to predict the compressive strength of concrete.

Limbah Beton Sebagai Material Agregat Halus Terhadap Kuat Tekan Karakteristik

Concrete waste from building construction can cause problems for the environment [1]. The use of fine aggregates from concrete waste can be a solution. The purpose of this study is to determine the value of aggregate characteristics and the value of concrete compressive strength from the utilization of concrete waste as substitution fine aggregate use the DOE (department of environment) method and referring to standards SNI. This study used 50% and 60% waste mortal substitution on sand. The results showed that the characteristics of fine aggregate and coarse aggregate met the characteristic requirements for fineness modulus sand of 2.65 (Zone 2) while the aggregate was roughly 6.44 (Zone 3). The value of compressive strength with 50% and 60% concrete waste substitution each obtained the value of characteristic compressive strength of 57.24 kg / cm² and 101.03 kg / cm². The value of using mortar waste as fine aggregate substitution gives a positive value to the quality of concrete. This is evidenced increase in the value of 14.89% in concrete waste substitution 60%.

PENGARUH PEMANFAATAN ABU PECAHAN TERUMBU KARANG DAN ABU SEKAM PADI SEBAGAI PENGGANTI SEMEN TERHADAP KUAT TEKAN BETON

Portland cement is a relatively expensive type of cement when used on constructions requiring simple requirements. Local material utilization using ash fragments of coral reefs and rice husk ash is one of the solutions. The objectives of this study is to determine the value of concrete compressive strength in each variation of cement replacement used were 2.5%, 5%, 7.5% and 10%, each variation consists of 70% ash fragment of coral reefs and 30% rice husk ash from the volume of cement used. The cube specimen with a size of (15x15x15) cm as many as 20 specimen were prepared. Concrete mixture according to SNI 03-2834-2000 used 0.5 cement water ratio and 60-100 mm of slump. The result of the compressive strength of concrete variation every percentage increase has increased and decreased from the result of the normal concrete compressive strength of 368.24 kg/cm2. Maximum increase occurred in the concrete compressive strength variation 7.5% of 384.76 kg/cm2 and decreased on the concrete compressive strength variation 10% of 367.40 kg/cm2.

Application of Mamdani and Sugeno Fuzzy Toward Ready-Mix Concrete Quality Control

The value of concrete compressive strength based on several methods of acceptance requirements of concrete in Indonesia to obtain a more economical concrete quality is recommended using SNI 03-2847-2002 rules as a reference in the evaluation and quality control of concrete. Fuzzy logic is different from ordinary digital logic, where the usual digital logic only recognizes two condition that is “yes” or “no”. While Fuzzy logic imitate the way of human thinking by using the concept of the pseudonym of a value. the Mamdani type and Sugeno type is resulted in the same decision, although there was a difference in the calculation of the final result but still within the same range of manual calculations with the calculation with the help of MATLAB. Both fuzzy can be applied in determining the quality of concrete because it produces the same decision. Although both fuzzy method can be used in determining the quality but the more recommended is the Mamdani type because Mamdani type result of calculation is closer to the actual result, and while there is input change is entered then the end result will change but Sugeno type while input change value is not too big the change then the end result also there will be no change.

PENGARUH METODE PERLAKUAN DALAM PERAWATAN BETON TERHADAP KUAT TEKAN DAN DURABILITAS BETON

Concrete strength is influenced by several variables, among others by its constituent material, mix design, workmanship, and curing. The objective of concrete curing is to maintain the concrete in certain conditions after the dismantling of the formwork hence the optimization of concrete strength can be achieved close to the designed strength. This study aims to determine the effect of concrete curing on its compressive strength. Designed concrete compressivestrength of 20 MPa with slump values of 60-100 mm to be used. The specimens are cube-shaped with 15 cm dimension. Concrete compressive strength tests were conducted at 28 days and 56 days of concrete age. The types of concrete curing consist of 9 variations, i.e., not treated, water immersed and water sprinkling. Optimum 28 days age of compressive strength of concrete obtained from specimens that immersed in fresh water, which was 31,3 MPa. The concretespecimens that were put outdoor without any curing and treatment generates second highest compressive strength value of 28.6 MPa. The 28 days age of concrete compressive strength values cured with water sprinkling with addition of burlap wrapping are still under the compressive strength of uncured concrete. Significant changes to the strength of cured concrete occurred at age of 56 days and uncured concrete strength decreased up to 19%. The optimum increase occurred in concrete cured with burlap sack wrapping and water sprinkling that was conducted routinely for 3 days by 27,84%. With increasing age (durability) the treated concrete has better strength.

Synergic effects of the substitution of Portland cement for water treatment plant sludge ash and ground limestone: Technical and economic evaluation

The coupled use of calcined clay and ground limestone has been a promising alternative to partially replace Portland cement due to the synergic effects between these two additions. Therefore, substituting calcined clay with a material of similar chemical composition, such as water treatment plant sludge ash (WTPSA), yields several environmental advantages. In this study, the pozzolanic activity of WTPSA was evaluated by determining the strength activity index (SAI) and using the modified Chapelle method. Statistical analyses were used to define the best conditions for WTPSA calcination and grinding. Response Surface Method (RSM) was used to find the Portland cement substitution content by WTPSA and limestone that result in higher concrete compressive strength values. The results of the evaluation of pozzolan activity of WTPSA showed that this material has the potential of being used as pozzolan. The joint analysis of the results confirms that calcination at 700 °C, residence time of 1 h, and grinding time of 1 h were the best conditions for treating WTP sludge. The optimal WTPSA and limestone content found by the Response Surface Method (RSM) were validated experimentally. Ternary mixtures containing WTPSA and limestone resulted in higher compressive strength than binary mixtures and plain cement, which shows the synergistic effect between the two materials. For compressive strength levels between 45 and 60 MPa, the ternary mixture composed of 15% WTPSA +7.5% ground limestone reduced Portland cement consumption from 34.7 to 38.4%.

The Compressive Strength of Coconut Fibers Reinforced Nano Concrete Composite

The compressive strength of the concrete reviewed in this study uses nanosilica and coconut fibers. The addition of coconut fibers to concrete contributes to the construction of sustainable and environmentally friendly building materials. The testing method carried out physically and mechanically. Testing the compressive strength of the nanoconcrete composite with variations in the amount of nanosilica which substituted with cement. Using variations of nanosilica composition, namely 0%, 0.5%, 1%, 1.5%, and 2% added with coconut fiber to determine the effect of compressive strength from nanoconcrete composite. The results obtained are the optimal value of concrete compressive strength with nanosilica is the addition of 2% nanosilica, which increases 43% of standard concrete. Moreover, on concrete with the addition of nanosilica and the addition of coconut fibers 1% test results in concrete compressive strength which is optimal in the addition of 0.5% nanosilica, which is 58% increase from normal concrete. The conclusion of this study that the addition of nanosilica and reinforced with coconut fiber will increase the compressive strength of concrete, this is an excellent composite material to get environmentally friendly building materials using.

ANALISA PENGARUH ADMIXTURE TERHADAP ABU TERBANG (FLY ASH) DAN BOTTOM ASH

With improve the quality of concrete is by using the addition of admixture. By adding admixture Silica fume and superplasticizer is expected to improve concrete quality in concrete using fly ash and bottom ash. The main objective of this research is to know the value of concrete compressive strength, slump test value, fresh concrete temperature and setting time in concrete using fly ash and bottom ash by 0%, 5%, 10%, 15%, 20% and 25% by weight of cement, with variations of silica fume 0%, 2%, 4%, 6 %, 8%, 10% of the weight of cement that has been reduced by the weight of fly ash and bottom ash and added with superplasticizer of 2% of the water requirement. The planned concrete quality was 41.7 MPa at 28 days, with the sample tested at age 7, 14, 28 days. Based on the results of the highest concrete compressive strength test for fly ash concrete (fly ash) is found in FA mixture variation 10%, SP 4%, SF 2% that is equal to 56,16 MPa. And for mixed bottom ash the highest compressive strength on mixed variation of BA 5%, SF 2%, SP 2% is equal to 49,82 MPa. Fresh concrete temperature variation of FA mixture 5%, SF 2%, SP 2% and BA 5%, SF 2%, SP 2% rose one degree from normal concrete temperature. Setting time generated on mixed concrete FA 5%, SF 2%, SP 2% has the fastest initial time setting ie 251 minutes of all variations of concrete mix.

The effect of thermal treatments on recycled alternative aggregates toward concrete properties

The objective of this research was to obtain the physical and chemical characteristics of the recycled waste material such as bricks, roof tiles, and ceramics waste. Chemical composition checked with XRF method. The physical characteristics were obtained by burning the recycled materials at 1000°C with ladle burner machine. SNI 03-2834-2000 was used as guideline in concrete making process. It could be seen that on the recycled materials had silica as their highest chemical composition. The specific gravity of recycled materials increased after the burning process while water absorption decreased after the burning process. Thermal treatment improved the quality of recycled alternative aggregates. Crystallization process started at 1000°C, resulted the decreasing value of material porosity and hardness. The decreasing value of concrete compressive strength was less than 8 % at the 25 % substitution of both ceramics and roof tiles. It showed that the recycled materials could be used as structural concrete based on SNI (Indonesian National Standard)

INVESTIGASI KEKUATAN BETON SILINDER GEOPOLIMER ABU AMPAS TEBU

The addition of elements such as pozzolan ingredients to concrete mixtures has been proven can increase the value of concrete compressive strength. This study aims to determine the microstructural effect on the replacement of 10% of Portland cement weight with bagasse ash (sugarcane bagasse). Scanning Electromicroscopphy Microscopphy (SEM / EDX) shows the dominant percentage of bagasse ash is Silica element 53% in addition to other elements such as Carbon (C) and Hydrogen (H). The C-S-H unsure bond pattern on concrete mortar shows a Type III bonding pattern at early ages and bonding patterns I and III on mortars that have reached the age of 28 days. Porosity level decreases with increasing age of concrete mortar. With the reduced porosity will increase the density and increase the compressive strength of concrete mortar. This porosity level is lower than that of concrete mortar without the addition of bagasse ash.Key words: Microstructure, silica, concrete mortar, compressive strength, porosity.

Nonlinear Finite Element Modeling of Different Cross-Sectional Shapes of Slender RC Columns Confined with CFRP Wraps

In the present study, nonlinear finite element analysis is carried out on the slender reinforced concrete columns wrapped using CFRP composite with different cross-sectional shapes having the same area. Thickness of the CFRP wraps, concrete compressive strength, corner radius, loading condition, slenderness ratio and column size are the main parameters of this study. According to this, four different eccentricity-to-section-height ratios, four different levels of the CFRP thickness in the strengthened specimens, the slenderness ratios of the length to the section-height (l/h) from 6 to 12, three various types of column size, concrete compressive strength values from 20 to 50 MPa and corner radiuses from 10 to 40 mm are considered. This paper presents a comparison of a numerical simulation using ABAQUS software, with the results of experimental tests by previous researchers to validate finite element models. It is shown that the predicted results by this numerical study are in reasonable agreement with the results of experimental studies. The results of this investigation also represented a considerable enhancement on the performance of strengthened columns with CFRP compared to unstrengthened columns.

Modeling of bentonite/sepiolite plastic concrete compressive strength using artificial neural network and support vector machine

Plastic concrete is an engineering material, which is commonly used for construction of cut-off walls to prevent water seepage under the dam. This paper aims to explore two machine learning algorithms including artificial neural network (ANN) and support vector machine (SVM) to predict the compressive strength of bentonite/sepiolite plastic concretes. For this purpose, two unique sets of 72 data for compressive strength of bentonite and sepiolite plastic concrete samples (totally 144 data) were prepared by conducting an experimental study. The results confirm the ability of ANN and SVM models in prediction processes. Also, Sensitivity analysis of the best obtained model indicated that cement and silty clay have the maximum and minimum influences on the compressive strength, respectively. In addition, investigation of the effect of measurement error of input variables showed that change in the sand content (amount) and curing time will have the maximum and minimum effects on the output mean absolute percent error (MAPE) of model, respectively. Finally, the influence of different variables on the plastic concrete compressive strength values was evaluated by conducting parametric studies.

Parametric study on the static compressive behaviour of concrete-filled double-skin sections consisting of corrugated plates

The compressive behaviour of Concrete-Filled Double-Skin tubular (CFDST) sections consisting of corrugated plates is investigated numerically in this study. Finite element simulations are employed to decipher more details on the compressive behaviour of numerous archetypes with different geometries and material properties. The results of these simulations reveal how the ultimate static compressive capacity of the intended sections may be affected by changing the geometric and material properties. Different cross-section shapes, dimensions and heights within the practical range are considered for the proposed archetypes. In addition, a wide range of concrete compressive strength values are assigned to the concrete infill of the archetypes. The ultimate axial capacity of almost all the intended CFDST archetypes is mainly dominated by concrete compressive strength. In conjunction with numerical simulations, different design formulations are also employed to predict the ultimate axial load-bearing capacity of CFDST sections.

Barrage Lock Concrete Porosity Evaluation Using X-Ray Microtomography

This paper deals with the use of X-ray microtomography in evaluating the porosity of barrage lock concrete. The main parts of the lock were built in the years 1914-1917. Its high and low heads were founded on 2.70 m thick concrete slabs. Samples for laboratory tests were taken by core drilling at half of the slab thickness. The compressive strength of the concrete was determined and the porosity of the concrete was evaluated using X-ray microtomography. The compressive strength values ranged from 17.3 to 37.3 MPa. The porosity examination results are compared with the destructively determined concrete compressive strength values.

Performance of sustainable SCC mixes with mineral additions for use in precast concrete industry

The aim of this research was to study the impact that different mineral powders have on the properties of self-compacting concrete (SCC) in order to obtain relations that make it possible to optimize their dosages for being used in precast concrete applications. Different combinations and contents of cement, mineral additions (active and inert), superplasticizers, and aggregates are considered. A new approach for determining the saturation point of superplasticizers is introduced. The fresh state performance was assessed by means of the following tests: slump flow, V-funnel, and J-ring. Concrete compressive strength values at different ages up to 56 days have been retained as representative of the materials’ performance in its hardened state. All these properties have been correlated with SCC proportioning. As a result, a number of recommendations for the precast concrete industry arise to design more stable SCC mixes with a reduced carbon footprint.

Influence of concrete matrix and type of fiber on the shear behavior of self-compacting fiber reinforced concrete beams

Steel fibers are known to improve shear behavior. The Design Codes (Eurocode 2 (EC2), Spanish EHE-08, Model Code 2010 and RILEM approach) have developed formulas to calculate the fiber contribution to shear, mainly focused on standard FRCs, i.e. medium strength concretes with a low content of normal strength steel fibers. However, in real applications other combinations are possible, such as high or medium strength concretes with high strength steel fibers of different lengths and geometry. An experimental program consisting of 12 self-compacting fiber reinforced concrete (SCFRC) I-type beams was carried out. All the beams had the same geometry and fiber content (50 kg/m3), and they were made with two different concrete compressive strength values and five different types of steel fibers and were tested for shear. The main conclusions reached were that the type of fiber substantially affects shear behavior, even when the Design Code formulas indicate similar contributions. The combination of high strength concrete matrixes with low strength fibers does not seem to be efficient. Also, the use of high residual flexural tensile strength values (e.g. fR3 or fR4) does not appear to be the most accurate reference value to calculate the beam shear strength in these cases. The present Design Codes consider standard FRCs, but their formulas should be revised for concretes with fibers of different strengths, slenderness and geometry, since these properties substantially affect shear behavior.

Splitting of concrete cover in steel fiber reinforced concrete: Semi-empirical modeling and minimum confinement requirements

The use of steel fiber reinforced concrete (SFRC) is becoming more and more common. Concerning bond of rebars to concrete, fibers provide passive confinement and not only improve bond performance but also affect the mode of bond failure. To analyze these aspects, a series of prismatic specimens have been subjected to the Pull Out Test, and an accurate model for predicting the mode of bond failure has been developed. The following factors have been considered: concrete compressive strength (30–50MPa), rebar diameter (8–20mm), concrete cover (between 30mm and 5 times rebar diameter), fiber content (up to 70kg/m3), and fiber slenderness and length. This model relates splitting probability to the factors considered. It has been proved that increasing fiber content restrains the risk of splitting failure. The favorable effect of fibers when preventing splitting failures has been revealed to be more important for higher concrete compressive strength values, which require higher concrete cover/diameter ratios for splitting failure to be prevented. Fiber slenderness and fiber length modify the effect of fiber content on splitting probability and therefore on minimum cover/diameter ratios required to prevent splitting failures.