Compressive Strength Of High-strength Concrete Research Articles

Different Statistical Modeling to Predict Compressive Strength of High-Strength Concrete Modified with Palm Oil Fuel Ash

The present study focuses on proposing various statistical models, such as linear regression (LR), nonlinear regression (NLR), and artificial neural network (ANN), to forecast the compressive strength of environmentally friendly high-strength concrete, incorporating waste agricultural material like palm oil fuel ash (POFA). A dataset of 105 experimental observations was compiled from existing literature to achieve this goal, which was subsequently partitioned into training and testing subsets. Each model was developed based on the training data and evaluated using the testing data. The performance of each proposed model was gauged using diverse statistical metrics like the coefficient of determination, mean absolute error, root mean square error, and scatter index to identify the most effective model. The findings indicate that using POFA with a finer particle size exerts a greater influence on the concrete's properties. The replacement was done using the weight method, and the predicted equation worked with the variation of the used rate of POFA from 0 to 60% of total binder weight. Substituting a portion of cement with POFA leads to a reduction in the heat of hydration and an extension of the setting time. The optimal percentage of POFA is 30%, yielding mechanical properties superior to those of the control mixture, particularly in the later stages of development. Among the models considered, the ANN demonstrates superior efficiency and accuracy in predicting the compressive strength of conventional concrete modified with POFA compared to LR and NLR models. This is evident in the ANN's higher R2 values of 52% and 16%, respectively, and a lower scatter index below 0.1%.

Behaviour and design of high-strength octagonal CFST short columns subjected to combined compression and bending

A systematic experimental and numerical investigation on the behaviour of octagonal concrete-filled steel tube short columns fabricated with S690 high-strength steel and C90 high-strength concrete, and subjected to combined compression and bending is reported in this paper. Experiments were firstly performed on twelve short column specimens with different plate width-to-thickness ratios. The experimental results and observations including the ultimate loads, load versus displacement responses and failure modes of the specimens were discussed. In supplementary to the experimental investigation, numerical investigation using a validated finite element model was performed to examine the behaviour of the structures with a wide range of plate width-to-thickness ratios, yield strength of high-strength steel and compressive strength of high-strength concrete that subjected to various combinations of compression and bending. Based on the experimental and numerical results, the applicability of existing design approaches in standards was also evaluated. The assessment shows that the design approaches provide conservative strength predictions for the high-strength octagonal concrete-filled steel tube short columns under combined compression and bending and can be applied to provide safe designs for the structures.

Early hydration and compressive strength of steam cured high-strength concrete based on simplex centroid design method

To obtain the precast concrete elements with high strength at an early stage, and strike a balance among mechanical properties, economic benefits and sustainable development. The heat of hydration, bound water content, calcium hydroxide content (CH), compressive strength and porosity of high-strength concrete (HSC) with cement–silica fume–fly ash micro-bead binder at 85 °C were investigated. The ternary binder formulations were the designed using simplex centroid design method. The results show that the appropriate amount of silica fume and fly ash micro-bead increases the total heat release and compressive strength of HSC, and reduce the CH content and porosity. Silica fume incorporation advances the induction period end time, while fly ash micro-bead increases the induction period end time. The pozzolanic reactivity of silica fume was greater than that of fly ash micro-bead. The effect of silica fume on 28 days strength was particularly obvious, and fly ash micro-bead have more significant improvement in early strength. The porosity shows a strong correlation with the compressive strength. The findings of this study are a worth reference for precast concrete manufacturers and can help to guide future studies.

Effect of Local Coarse Aggregates on the Compressive Strength of High Strength Concrete

This study investigates the effect of different types of local coarse aggregate, available in Saudi Arabia, on the strength of high-strength concrete. The utilized coarse aggregates are basalt and two different aggregates of limestone, denoted as limestone 1 and limestone 2. The results of 7 and 28 days compressive strength with different percentages of Micro Silica (MS) (i.e. range from 0 to 10%) show that the compressive strength of high strength concrete (HSC) is influenced by the type of coarse aggregate. Limestone 2 reaches the highest compressive strength followed by the types limestone 1 and then basalt. Properties of coarse aggregate influence the compressive strength of HSC, such as impact value (AIV), and texture. Also, the impact value variation between saturated surface dry (SSD) and dry conditions of the coarse aggregate affect significantly the compressive strength of HSC.

Effect of marble powder content on compressive strength and water absorption of high-strength concrete

This paper presents the effect of marble powder content on compressive strength and water absorption of high-strength concrete to expand the utilization of such waste in the construction industry and to reduce the Portland cement production which negatively affects the environment. Mixture proportion of reference concrete without marble powder was designed as per TCVN 10306:2014 with a designed compressive strength at least of 60 MPa and slump of 16 ± 2 cm. To evaluate the effect of marble powder content on compressive strength and water absorption of hardened concrete, the Portland cement was replaced by the marble powder at levels of 0, 5, 10, 15, and 20% by mass. Experimental results showed that the marble powder significantly affected the engineering properties of fresh and hardened concretes, in detail: the replacement of Portland cement by the marble powder from 0 to 20% increased the slump of fresh concrete from 16.0 to 20.5 cm, and the void volume of hardened concrete at the age of 28 days from 2.66 to 4.79%, resulting in the reduction of compressive strength by 2.48–18.60% and the increase in water absorption by 1.59–3.79% when comprared with the reference concrete with 0% marble powder. However, the value of compressive strength at the age of 28 days of hardened concrete using 5–20% marble powder reached 60.94–73.01 MPa, ensuring the requirement in terms of compressive strength of high-strength concrete. In conclusion, the utilization of marble powder as the Portland cement replacement in a range from 5–20% was feasible in making high-strength concrete with compressive strength of above 60 MPa.

EVALUASI KUAT TEKAN BETON MUTU TINGGI YANG MENGANDUNG TULANGAN SATU ARAH

The concrete compressive strength in existing buildings can be determined by the destructive method (DM) and the non-destructive method (NDM). The non-destructive method can be carried out to determine the distribution of the compressive strength of concrete in structural elements, but the value given is not absolutely representative of the actual compressive strength of the concrete. To find out the actual compressive strength of concrete is to carry out destructive tests such as core drilling oncrete. In general, core concrete is not allowed to have reinforcement, but this is sometimes unavoidable. The purpose of this study was to evaluate the compressive strength of high-strength concrete due to the content of reinforcement in the concrete. This study used a concrete cylindrical specimen with a diameter of 10 cm with a variation of the ratio L/D = 1 and L/D = 2. One reinforcement was placed on 1/4 L and 1/2 L of each specimen horizontally with the number of specimens per variation being 5 specimens. The total number of cylindrical specimens was 30 specimens. In this study, specimens without reinforcement were also made as control specimens. Based on the results, it was found that the value of the reinforcement content factor (C 2 ) was still relevant to be used for the L/D = 2 specimens because it still had a deviation below 5%. Meanwhile, for L/D = 1 multiplication with the value of C 2 shows a deviation above 5%. The position of the reinforcement that was getting closer to the half height of the specimens decreases the compressive strength of high-strength concrete.

Pengaruh Penggunaan Ternary Blend Fly Ash Dengan Volume Tinggi dan Abu Sekam Padi Terhadap Kuat Tekan Beton Mutu Tinggi

This study aims to find the effect of ternary blended: cement, fly ash (FA), and rice husk ash (ASP) on the compressive strength of high-strength concrete. The composition of FA and ASP used for cement replacement were 0%, 10% ASP, 30% FA, 10% ASP+30% FA, 10% ASP+40% FA, and 10% ASP+50% FA. The water-cement factor (FAS) and binder used are 0.3 and 500 kg/m3 fresh concrete, respectively. The specimens used for compressive strength is cubes of 100×100×100 mm with tests at the age of 1, 3, 7, 28, and 56 days. The results showed that the use of 10% ASP increased the compressive strength of the concrete compared to the control concrete but required more superplasticizers. The use of 30% FA as a cement substitute showed a decrease in compressive strength compared to control concrete but reduced the use of superplasticizer. The use of a combination of FA and ASP as a substitute for cement showed a decrease in compressive strength under control concrete and concrete using 30% FA. The decrease in the compressive strength of concrete with the combination of ASP and FA is beyond the initial expectation. This may be due to the disproportionate use of FA compared to ASP so that the reaction that occurs is not optimal to form calcium silicate hydrate (CSH). However, the use of ternary blended cement, FA, and ASP still has added values which is better workability than without using FA.

Degradation Law of Material Properties of High Strength Concrete in Deep Topsoil Environment

The performance degradation of concrete materials is carried out under the coupling effect of various factors of natural and mechanical environment, which is a very complex process of interaction and superposition, and is also the fundamental reason for the reduction of reliability and life span of concrete structures. There are a lot of corrosive gaseous, liquid and solid media in the environment of reinforced concrete shaft wall, which seriously degrades the properties of reinforced concrete materials. In this paper, the mechanical properties of high-strength concrete are studied through physical simulation test. It is found that the change law of high-strength concrete strength is different in different environments. The compressive strength of high-strength concrete is in a gradually decreasing stage in environment 1 and environment 2, but it is in an increasing stage in environment 3, and then it will enter a decreasing stage with the increase of cycle. The variation law of compressive strength of high-strength concrete in the same strength grade and different environment is also different. Finally, the prediction model of compressive strength degradation of high-strength concrete is established, which provides corresponding guidance for theoretical design and practical engineering.

A concrete damage plasticity model for predicting the effects of compressive high-strength concrete under static and dynamic loads

In this paper, a concrete damage plasticity model is presented for simulating the behaviour of high-strength concrete; C60, C80 and C110 under static and dynamic loading conditions. This model is based on the ground-breaking studies recorded in recently completed studies to improve and develop the original concrete damage plasticity (CDP) model in ABAQUS software. In this CDP model, the stress-strain curves in compressive behavior and tensile behavior during the softening phase (after stress reaches peak strength) consider the effect of mesh size in Finite Element model. Through recently published results, these curves show many advantages compared to the previous studies. At the same time, the tensile damage variable (dt) and the compressive damage variable (dc) are presented using an exponential function to replace the values reported in previous researches. Especially, in the case of dynamic problems, the Dynamic Increase Factor (DIF) according to the fib MODEL CODE 2010 (MC2010) is used in this study as a significant parameter to determine the effects of strain rate on compressive strength of high-strength concrete. To prove the reliability and effectiveness of the proposed model, numerical simulation of the static compressive tests is implemented to verify its suitability in case of static loading problems. Then, Split-Hopkinson pressure bar (SHPB) test is simulated to determine the level of accuracy of DIF in simulating the dynamic loading problems. The results show that the CDP model introduced in this study has an acceptable agreement with the experimental results for both cases; static and dynamic loading conditions, with high reliability.

A data-driven study for evaluating the compressive strength of high-strength concrete

A data-driven study for evaluating the compressive strength of high-strength concrete

Nonlinear Mechanical Effect of Free Water on the Dynamic Compressive Strength and Fracture of High-Strength Concrete.

It is well-known that the effect of interstitial fluid on the fracture pattern and strength of saturated high-strength concrete is determined by qualitatively different mechanisms at quasi-static and high strain rate loading. This paper shows that the intermediate range of strain rates (10−4 s−1 < < 100 s−1) is also characterized by the presence of a peculiar mechanism of interstitial water effect on the concrete fracture and compressive strength. Using computer simulations, we have shown that such a mechanism is the competition of two oppositely directed processes: deformation of the pore space, which leads to an increase in pore pressure; and pore fluid flow. The balance of these processes can be effectively characterized by the Darcy number, which generalizes the notion of strain rate to fluid-saturated material. We have found that the dependence of the compressive strength of high-strength concrete on the Darcy number is a decreasing sigmoid function. The parameters of this function are determined by both low-scale (capillary) and large-scale (microscopic) pore subsystems in a concrete matrix. The capillary pore network determines the phenomenon of strain-rate sensitivity of fluid-saturated concrete and logistic form of the dependence of compressive strength on strain rate. Microporosity controls the actual boundary of the quasi-static loading regime for fluid-saturated samples and determines localized fracture patterns. The results of the study are relevant to the design of special-purpose concretes, as well as the assessment of the limits of safe impacts on concrete structural elements.

Experimental investigation and prediction of compressive strength of high-strength concrete containing waste ceramic powder using gene expression programming

The high volume of carbon dioxide produced in cement plants and the feasibility of reusing waste materials from factories in recent years has become one of the main concerns of research centers and environmental associations. Therefore, the main purpose of this research is to evaluate the feasibility of reusing waste materials with a focus on waste ceramic powder (WCP), as a semi-active aluminosilicate material that can be replaced as a percentage of cement used in concrete. WCP, in addition to activating the potential of using a waste material in concrete, can also reduce cement consumption. Therefore, in this research, cement replacement percentages between 0 and 50% in three water to cement ratios of 0.3, 0.4 and 0.5 in 24 concrete mixtures have been used to perform compressive strength tests. In order to provide a usable computational model, the gene expression programming (GEP) method has been used to predict the compressive strength of the samples. The results of experimental research indicate that in the ratio of water to cement 0.3 at the age of 90 days, the sample containing 20% of WCP has reached a compressive strength of 72.57 MPa. This result is almost equal to the control sample and therefore the use of this percentage is recommended for this ratio of water to cementitious materials. Finally, the results indicate the very good performance of the GEP method by increasing the number of chromosomes and increasing the correlation coefficient between experimental and numerical data up to 98%. Therefore, the GEP method has a significant advantage over other methods by providing an analytical relationship and high accuracy.

Compressive strength prediction model of high-strength concrete with silica fume by destructive and non-destructive technique

The study proposes a new model for estimating the compressive strength of high-strength concrete using destructive and non-destructive testing. The effect of silica fume replacement level and its cementing efficiency factor on compressive strength and ultrasonic pulse velocity (UPV) were experimentally examined. In the present work, the cementing efficiency factor (k) for silica fume at different percentage replacement level has been assumed, and at the constant water-to-binder ratio, the compressive strength has been obtained. An exponential relationship is proposed between UPV and compressive strength with a high correlation coefficient. A statistically noteworthy model with a high correlation coefficient R2 > 0.90 is established to study the influence of the variables (%SF and k) on UPV results. Finally, the two proposed models were amalgamated to develop a new model to predict the 28-day compressive strength of high-strength concrete. The validity of the model has been verified with the results obtained by different researchers on different types of specimens. The proposed new model is for the strength range of the 40–75 MPa.

Applications of Gene Expression Programming for Estimating Compressive Strength of High-Strength Concrete

The experimental design of high-strength concrete (HSC) requires deep analysis to get the target strength. In this study, machine learning approaches and artificial intelligence python-based approaches have been utilized to predict the mechanical behaviour of HSC. The data to be used in the modelling consist of several input parameters such as cement, water, fine aggregate, and coarse aggregate in combination with a superplasticizer. Empirical relation with mathematical expression has been proposed using engineering programming. The efficiency of the models is assessed by statistical analysis with the error by using MAE, RRMSE, RSE, and comparisons were made between regression models. Moreover, variable intensity and correlation have shown that deep learning can be used to know the exact amount of materials in civil engineering rather than doing experimental work. The expression tree, as well as normalization of the graph, depicts significant accuracy between target and output values. The results reveal that machine learning proposed adamant accuracy and has elucidated performance in the prediction aspect.

Performance of High-strength Concrete Made with Recycled Ceramic Aggregates (Research Note)

Recent scientific concerns to achieve sustainability in construction have suggested the implementation of using recycled aggregate in concrete; because it has the potential to reduce the demand for extraction of natural raw materials and decrease the volume of wastes landfilled. In this respect, this study aims to investigate the suitability of using ceramic tile (CT) and ceramic sanitary (CS) wastes as coarse aggregate in production of high-strength concrete (HSC). Different concrete mixes were produced by partial replacement of 10, 20 and 30% of natural coarse aggregate with recycled aggregates. Besides investigating the characteristics of recycled aggregate, slump, compressive strength, initial and final absorption and chloride ion penetration depth of HSC specimens were evaluated and compared with that of plain HSC. Results showed that using recycled ceramic aggregates increased the superplasticizer dosage to maintain the target slump. Although by incorporation of high percentage of CT or CS aggregate, compressive strength of HSCs was reduced compared with reference HSC, it is possible to produce HSC with 28-days compressive strength higher than 60.7 MPa. Moreover, the absorption and chloride ion penetration depth of recycled aggregate incorporated HSC were higher than those of estimated for plain concrete. Generally, waste ceramic aggregate at optimum replacement ratio can be used in the sustainable development of HSC.

Behavior of Fiber-Reinforced Polymer-Confined High-Strength Concrete under Split-Hopkinson Pressure Bar (SHPB) Impact Compression

Fiber-reinforced polymer (FRP) has become increasingly popular in repairing existing steel-reinforced concrete (RC) members or constructing new structures. Although the quasi-static axial compression performance of FRP-confined concrete (FCC) has been comprehensively studied, its dynamic compression performance is not well understood, especially the dynamic compressive behavior of FRP-confined high-strength concrete (FCHC). This paper presents an experimental program that consists of quasi-static compression tests and Split-Hopkinson Pressure Bar (SHPB) impact tests on FRP-confined high-strength concrete. The effects of the FRP types, FRP confinement stiffness, and strain rate on the impact resistance of FCHC are carefully studied. The experimental results show that the strain rate effect is evident for FRP-confined high-strength concrete and the existence of the FRP greatly improves the dynamic compressive strength of high-strength concrete. An existing strength model is modified for impact strength of FCHC and the predicted results are compared with the test results. The results and discussions show that the proposed model is accurate and superior to the existing models.

Effect of maximum coarse aggregate size on dynamic compressive strength of high-strength concrete

Dynamic increase factor (DIF) is a measure of the rate effect in the analysis and design of structures subjected to impact or impulsive loads. A variety of DIFs have been suggested based on the results of split Hopkinson pressure bar (SHPB) tests, which is the test technique most commonly used to obtain dynamic material properties. However, due to the lack of a standard test method and some limitations in the SHPB equipment, most SHPB tests have been conducted for mortar or concrete specimens containing small size coarse aggregate that is very different from the actual concrete used in construction. The DIFs that are provided in most structural design codes are based on these test results. Therefore, it is necessary to investigate the effect of coarse aggregate size on the dynamic concrete compressive strength. In this study, a series of SHPB tests were conducted for mortar and concrete specimens with various maximum aggregate sizes. The test results indicated that the larger maximum coarse aggregate sizes induce larger heterogeneity of specimens. On the other hand, the pure rate DIFs did not exhibit a dependency on the maximum coarse aggregate size. Based on these results, guidance as to the maximum coarse aggregate size of concrete specimens for SHPB tests is provided.

Effect of Elevated Temperature on Meso- and Micro-Structure and Compressive Strength of High-Strength Concrete and Mortar Containing Blast-Furnace Slag

Effect of Elevated Temperature on Meso- and Micro-Structure and Compressive Strength of High-Strength Concrete and Mortar Containing Blast-Furnace Slag

Critical parameters for the compressive strength of high-strength concrete

This study investigates the influence of several material properties underlying the failure mechanism of high-strength concrete (HSC) under uniaxial compression. An experimental-numerical characterization of a single inclusion block (SIB) – an idealized composite comprising of a granite cylindrical core embedded within a high-strength mortar (HSM) matrix – is first carried out. Parametric studies are next conducted with the calibrated SIB model, to identify the critical parameters governing the failure of the idealized composite. The qualitative understanding obtained from the SIB is then utilized to design a series of experiments, exploring the extent of influence of the identified critical parameters on the compressive strength of HSC. Complementary experimental data in literature are also examined. For the range of specimens considered, it is found that the lateral strain capacity of mortar matrix has the most influence on the compressive strength of HSC.

Assessment and optimization of thermal and fluidity properties of high strength concrete via genetic algorithm

This paper proposes a Response Surface Methodology (RSM) based Genetic Algorithm (GA) using MATLAB® to assess and optimize the thermal and fluidity of high strength concrete (HSC). The overall heat transfer coefficient, slump-spread flow and T50 time was defined as thermal and fluidity properties of high strength concrete. In addition to above mentioned properties, a 28-day compressive strength of HSC was also determined. Water to binder ratio, fine aggregate to total aggregate ratio and the percentage of super-plasticizer content was determined as effective factors on thermal and fluidity properties of HSC. GA based multi-objective optimization method was carried out by obtaining quadratic models using RSM. Having excessive or low ratio of water to binder provides lower overall heat transfer coefficient. Moreover, T50 time of high strength concrete decreased with the increasing of water to binder ratio and the percentage of superplasticizer content. Results show that RSM based GA is effective in determining optimal mixture ratios of HSC.