Physical Properties Of Concrete Research Articles

The Study of the Strength Properties of Galvanized Iron (GI) Fiber Reinforced Concrete

The use of concrete with randomly distributed metallic or non-metallic fiber is now prominent in concrete engineering and metallic fiber has been reported to have a better contribution to concrete mechanical properties. The utilization of locally available galvanized iron or metallic fiber as a bridging material which is a new technique in Bangladesh has the ability to surprisingly improve concrete physical properties. This research was, therefore, conducted to compare the concrete performance of GI fiber and steel fiber using previous literature as well as the suitability of GI fiber as a supplant to steel fiber in the concrete industry. This was achieved through the evaluation of the compression, tension, and brittleness of concrete with ‘Galvanized Iron’ fiber using several cutting lengths of 20 mm and 40 mm with multiple mix proportions including 1.0%, 1.5%, 2.0%, and 2.5% by volume of the concrete. The results showed the fiber with a large cut length of 40 mm and proportion lesser than 2.5% performed well than 20 mm with proportion 2% in reference to the plain concrete. Moreover, the incorporation of a 2.0% proportion of galvanized iron fiber with 40 mm length was observed to have exhibited crowning increment for both concrete compression and tension by 16.1% and 89.2% correspondingly contrasted to the control specimen. A further increase in the percent of fiber content 2% led to a reduction in the compression and tension for both 20 mm and 40 mm lengths while a significant reduction in brittleness for galvanized iron fiber reinforced concrete was observed in contrast to the control specimen. Furthermore, the inclusion of 1.0%–2.5% GI fiber with a 40 mm length reduced concrete brittleness by 56.9% - 65.5 % in comparison with the control specimen. Therefore, the inclusion of galvanized iron (metallic) to enhance the physical properties of concrete was deduced to be one of the startling stratagems

Numerical Meshless Method in Conjunction with Bayesian Theorem for Electrical Tomography of Concrete

Electric potential measurement technique (tomography) was introduced as a nondestructive method to evaluate concrete properties and durability. In this study, numerical meshless method was developed to solve a differential equation which simulates electric potential distribution for concrete with inclusion in two dimensions. Therefore, concrete samples with iron block inclusion in different locations were cast. Then, via a pair of electrodes attached to the samples, DC current was injected into concrete and electric potential was measured through 14 electrodes placed in the perimeter of the samples. In total, 35 different pair electrode configurations were planned for current injection. Bayesian theorem was employed to perform probabilistic tomography as well as to calculate the optimal shape coefficient in the numerical meshless method. Results of this study indicated that shape coefficient in multiquadratic radial-based function (MQ-RBF) model does significantly depend on boundary conditions. Furthermore, when the main current line is long, distribution of random variables c and e fits well with normal distribution, which is in agreement with the study assumption. Also, results reveal that probabilistic tomography is more precise than deterministic tomography even without using prior functions. Experimental results showed that MQ-RBF model has good performance in electrical tomography. This is due to uncertainty of concrete physical properties in real conditions which can be resolved by meshless method using optimization of shape coefficient.

Effect of Calcium Stearate in the Mechanical and Physical Properties of Concrete with PCC and Fly Ash as Binders.

This work aims to study the effect of Ca(C18H35O2)2 (calcium stearate) on the properties of concrete by using Portland composite cement (PCC) and fly ash as binders. The calcium stearate content used in the concrete here consists of 0, 1, 5, and 10 kg per m3 of concrete volume, or alternatively, 0 to 2.85% by the weight of cement. We have performed several tests for each of the contents, namely, compressive strength, water absorption, chloride ion infiltration, and accelerated corrosion tests. According to the testing, we have found that with the addition of calcium stearate at 1 kg/m3 in self-compacting concrete (SCC) with 10% fly ash, the mechanical and physical properties of SCC can be improved significantly when compared to the SCC without fly ash and calcium stearate, resulting in a stable compressive strength, lower water absorption, lower chloride ion infiltration, and lower degree of corrosion attack.

Thermal and physical properties of concrete containing glass after cooling in different paths

AbstractThis paper studies the thermal and physical properties of concrete containing glass at different cooling paths. The coarse aggregates in the concrete samples with glass aggregate are 50% calcareous sand and 50% glass. After heating at different temperature, the samples are cooled at water (thermal shock) and air (thermal aging), and then dried. Afterwards, surface color, mass, thermal conductivity, compressional wave velocity, and compressive strength of the samples are measured. The results show that the color change is related to the content of Ca(OH)2. The mass change is mainly related to the evaporation of free water and chemically bond water and the mass loss of thermal shock samples is lower than that of thermal aging samples. The thermal conductivity of concrete made with limestone is higher than that of concrete made with glass. Thermal shock has little effect on the wave velocity and compressive strength of the concrete. The strength of the samples made without glass is significantly higher than that of the samples made with glass. Thermal shock causes a denser microstructure than thermal aging due to the rehydration of the components. The color change, mass loss, thermal conductivity, wave velocity, and compressive strength of the concrete are related to the rehydration of components in concrete and the relationships between these parameters show good linear relationships.

Characterization of processed lightweight aggregate and its effect on physical properties of concrete

The plastic because of its lightweight and flexibility to adopt the required shapes has led in an enormous increase in production of plastic products during recent years. To minimize the negative environmental impacts of plastic waste, many industrial sectors have tried to recycle and utilize the plastic waste. Among the other sectors, concrete industry can be considered as one of the alternatives such as to use the recycled plastic as aggregate replacement in concrete. A processed lightweight aggregates (PLA) has been manufactured using the plastic waste and other local materials using a compression moulding press technique. The detailed characterization of the PLA was also conducted. In addition, the effect of PLA incorporation on the physical properties of concrete along with effect of curing temperature on the compressive strength was also tested. The addition of manufactured aggregate in concrete has increased the Poisson’s ratio, thermal conductivity values while the density, and compressive strength were found to be reduced as compared to control mix. It was also noticed that PLA concrete can be cured at temperatures up to 30 °C, without significantly affecting compressive strength. The PLA has shown the prospective to be used in lightweight concrete applications.

Effect of sulfate solution concentration on the deterioration mechanism and physical properties of concrete

Effects of sodium sulfate solution concentration and erosion age on axial compressive strength, sulfate ion distribution, dynamic elastic modulus, electrochemical performance and load–displacement curves of concrete were investigated. Based on the chemical thermodynamics theory, the internal relationship between sodium sulfate solution concentration and sulfate products was deduced. The porosity and pore distribution, phase composition, Nyquist spectrum, micro structure and morphology of concrete before and after sulfate attack were also analyzed by different testing instruments. The results indicate that the axial compressive strength and load–displacement curves of concrete first increase and then decrease with increasing sodium sulfate solution concentration. With increase of erosion age, the lower the strength grade of concrete is, the larger the reduction of axial compressive strength of concrete attacked by sulfate. The main products of sulfate attack are claviform ettringite and lamellargypsum, which play double effects on performance of the concrete. The sulfate ion content in concrete surface increases with the increasing of sulfate solution concentration, and it also increases first and then decreases until to a certain value with depth. The transverse and longitudinal dynamic elastic moduli of concrete attacked by sulfate solution change with increasing of the sulfate solution concentration. The envelope curves of the waveform change of transverse and longitudinal dynamic elastic moduli of concrete can be represented as exponential function. The change of electric resistance of pore solution and charge-transfer resistance increases with sulfate solution concentration, which indicates the micro structure of concrete specimens are degraded by sulfate attacked.

Recycling of disposal Polypropylene Blister Tablets and Strapping ties as fiber reinforcement for Pervious concrete

Pervious concrete (PC) was introduced as a solution for the runoff from rainfall. To insure high porosity, pervious concrete should contain limited quantities of fine aggregate, which adversely effects concrete mechanical properties. As an attempt to improve PC mechanical properties, fibers were added to concrete matrix. As PC is allows water to pass through it, metal fibers are uncourageous to be added to it. Plastic fibers were selected as an alternative to metal fibers to be added to PC. Concrete physical and mechanical properties were studied for mixtures containing different quantities of fibers. Tests results showed a slight improvement in concrete compressive strength (0.48% to 1.44%) as fibers were added. The addition of fibers improved splitting tensile strength by (6.36% to 27.67%). As adding fibers, concrete flexural strength increased by (11.37% to 24.17%) compared to the reference mixtures. of PC. Concrete physical properties (Density, Porosity and permeability) were also investigated. The addition of fibers to concrete has a slight effect on (density, porosity and permeability).

Effect of Wood-Particles Aggregate Percentage on Some Physical Properties of Concrete

This paper is focused on light-weight aggregate concrete with wood particles and its issuesaccording to physical and thermal properties. The experimental work for the estimation of density, absorption and thermal conductivity of light-weight wood-particles aggregate concrete is presented. Wide range of wood-particles percentages were used in the experimental work. The thermal conductivity is related to the air-dry density of wood-particles aggregate concrete. The relation is liedclosely within the predictions presented in ACI 213 committee report. The range of air dry density was about 1400 to 1900 kg/m3.

Effect of cellulose nanofibrils and nanocrystals on physical properties of concrete

The study on the physical properties and durability of concrete with admixture cellulose nanofibrils (ACNF) and cellulose nanocrystals (CCNC) was presented in the paper. The following characteristics of the concrete were defined: absorptivity, density, apparent density, open porosity, contact angle (CA), surface free energy (SFE), compressive strength, flexural tensile strength, freezing-thawing resistance. The use of ACNF and CCNC results in different wetting and adhesion properties of concrete. The highest CCNC addition yielded a concrete with the lowest CA with water and the highest SFE values that evidenced the increased adhesion properties and wettability. The microstructure of concrete with ACNF and CCNC and distribution of cracks and pores within them were investigated by scanning electron microscope (SEM). CCNC improves the freezing-thawing resistance.

Changes in the Crystal Structure of Cement Mortars Subjected to a High Temperature

During the fire, structures of a building are exposed to the effect of a high temperature. As a result, the strength parameters and physical properties of concretes and cement mortars undergo change. Their range depends on the time and temperature of the fire. Describing the changes of the internal structure of concretes and mortars resulting from a fire is important in the fire diagnostics of the structures. The paper presents the results of an original research project, within which there was an attempt to relate changes in mechanical properties of the cement mortars with changes in the crystal structure of cement paste. For this purpose, the authors prepared cement prisms, which were heated at various temperatures that occur during a fire after 28 days of their curing. Then, the samples were subjected to compressive strength tests and tests of a structure and a phase composition using an electron scanning microscope. Scanning microscopy is a precious research method that allows observing surfaces of various materials with magnifications from x50 to even x1000000 at a very big sharpness depth. The tests conducted by the authors showed that the effect of fire and of the gradient of high temperatures on the executed samples causes the deterioration of the cement paste in the form of changes in physico-mechanical properties and in its internal structure. As the temperature increases, the compressive strength of the paste decreases gradually and proportionally. The SEM analysis also showed that the change in the physical parameters of the cement paste is reflected in its phase composition.

Capillary tension theory for predicting shrinkage of concrete restrained by reinforcement bar in early age

Abstract In this study, we proposed a method for predicting early shrinkage of concrete restrained by reinforcement bar based on capillary tension theory and microstructure pore of concrete. Concrete specimens with two different strength grades and four different reinforcement ratios were prepared. The pore structure, shrinkage, and physical properties of concrete were investigated at ages of 3, 7, and 28 days. Experimental results show that the reinforcement bar changed the pore structure of the concrete. The pore structure size of the concrete increased linearly with increase in the reinforcement ratio. Concrete shrinkage restrained by reinforcement bar decreased. It was because of the co-deformation between concrete and reinforcement bar and restrictions on capillary stress. The predicted values of shrinkage of concrete restrained by reinforcement bar were in good agreement with measured values.

Effect of Rice Husk Ash and Water-Cement Ratio on Strength of Concrete

In present status quo, number of researcher are working on waste materials as potential supplement for any of the constituent of concrete to cope with sustainable development. As, the ingredients which constitute the body and give strength to concrete are natural available limited material and has to deplete one day. Thus, there is desperately need of alternate that may replace the limited natural resources. In this regard, this study focuses the rice husk ash (waste stuff) as partial replacement of cement and its possible impact on strength of concrete. In addition, this research work also this research work is conducted to investigate the effect of water-cement ratio on the strength of concrete at 10% partially replacement of Rice husk ash (RHA) by the weight of cement. RHA is a mineral admixture obtained by burning husk at certain temperature. Since as per pervious researches, the physical and chemical properties of RHA are very reactive Pozzolans and possess binding properties so can be used as cement supplement. Therefore, for laboratory experimental work, total 144 cubical and 72 cylindrical. In this research, number of concrete specimens were cast and tested at 1:2:4 mix ratio with various w/c ratios i.e. 0.45, 0.50 and 0.60. Further, at each specified water-cement ratio, two mechanical properties (compressive and splitting tensile strength) were determined in Universal Testing Machine (UTM). These physical properties of concrete were investigated at 7, 14, 28 and 56 days curing period. The experimental results show that the compressive strength gets increased up to 14.51% and tensile splitting test strength increased up to 10.71% at the w/c ratio of 0.45. The workability of plain fresh concrete at all w/c ratios is slightly greater than the workability of concrete blended with 10% RHA. Thus, RHA improves the properties of concrete when used in specific amount. As a result, it can reduce the overall cost of construction and it will reduce the adverse environmental effect.

Effect of fine and coarse recycled concrete aggregate on the mechanical behavior of precast reinforced beams: Comparison of FE simulations, theoretical, and experimental results on real scale beams

In this work, we present the effect of using coarse and fine recycled aggregate jointly as a partial replacement of natural aggregate in self-compacting concrete in the mechanical performance of precast beams. The replacement levels of recycled aggregate were set to 0%, 20%, 35%, and 50% of the total amount of aggregate. The effect of the partial replacement of coarse and fine recycled aggregate jointly in the mechanical and physical properties of concrete was analyzed at 28 days. Then, a total of 8 reinforced beams were cast (two beams per each concrete studied) to determinate the effect of the partial replacement of recycled aggregate. One of the beams of each concrete was designed and tested to determine the flexural strength, and the other beam was used to determine the shear strength. The flexural and shear strengths obtained from the tests of real-scale beams were compared with theoretical analyses based on standards EC-2 and EHE-08, and by computational analyses based on the finite element method (FEM). These comparison, allowed us to assess the use of theoretical and computational models as tools to predict the mechanical behavior of real scale beams under different loading conditions (flexural and shear tests) when different proportions of recycled aggregate are used. According to the results, for the shear test, the theoretical models based on standards can be applied for concrete structures regardless of the percentage of recycled aggregate, without losing accuracy in comparison with beams made of plain concrete. In contrast, under flexural conditions, the theoretical models based on the standards are only applicable when considering 20% or less recycled aggregate. In general, computational models based on FEM show good agreement with experimental results in all the studied cases.

Effect of Water Content and Water Type on the Physical Properties of Concrete

Effect of Water Content and Water Type on the Physical Properties of Concrete

Properties of Self-curing High Strength Concrete by using Baby Polymer Diapers

This study investigates the self-curing concrete using baby polymer diapers as substitute method of curing process in order to improve mechanical and physical properties of concrete. Three different proportion of baby polymer diapers which are 1%, 3% and 5% were mix with concrete. Slump, compressive strength and drying shrinkage test were performed in order to study the workability, strength and durability of the concrete. All concrete were tested for 1, 3, 7, 14, and 28 days for drying shrinkage test. Meanwhile, all concrete were test at 3, 7 and 28 days for compressive strength test. Compressive strength of concrete containing 5% baby polymer diapers show the highest strength at 28 days compared to others percentage. Thus, it indicates that application of baby polymer diaper as self-cure agent can improve the concrete performances.

Effect of Nanotechnology on Physical Properties of Concrete

The focus of this paper is the study of effect of nanotechnology on the concrete. It shows that:The control of moisture in buildings is key to their durability, functionality, health and efficiency. Concrete which is thoroughly soaked with water is less rigid in compression than concrete with is thoroughly dried out. Use of nano SiO2 could significantly increase the compressive for concrete, containing large volume fly ash, at early age and improve size distribution. The self-healing polymer could be especially applicable to fix the microcraking in bridge, piers and columns. With the hycrete waterproofing system, concrete is batched with hycrete liquid admixture to achieve hydrophobic performance. Concrete treated by hycrete shows less than 1% absorption. This product has positive effects on the environment. Green additive has lower cost than the materials they replace. Finally, two solutions are given to have appropriate material behavior: nanotechnology and green additive.

Possibilities of use of waste sulfur for the production of technical concrete

The article presents the results of research that focused on the selected physical properties of sulphur waste stabilized in concrete. The influence of replacing part of the cement on the physical properties of concrete was studied in the article. The concrete mixtures was modified by pure waste sulphur in amounts of 10, 20 and 30wt% of the cement. The results show that using sulphur admixture can reduce concrete absorptivity and make concrete more watertight.

Possibilities of use of waste sulfur for the production of technical concrete

The article presents the results of research that focused on the selected physical properties of sulphur waste stabilized in concrete. The influence of replacing part of the cement on the physical properties of concrete was studied in the article. The concrete mixtures was modified by pure waste sulphur in amounts of 10, 20 and 30wt% of the cement. The results show that using sulphur admixture can reduce concrete absorptivity and make concrete more watertight.

Flexure response of thermal loaded concrete specimens by acoustic emission method

The response to fire of concrete structural members depends on the thermal, mechanical, and deformation properties of concrete. These properties vary significantly with temperature depending on the composition and characteristics of the concrete batch mix as well as heating rate and other environmental conditions. The paper presents the effects of a high temperature on selected physical properties of concrete. The main aim of the article is the evaluation of monitoring concrete properties loaded in a few thermal steps up to 1200 °C. Therefore, the concrete specimens were heated in a programmable laboratory furnace at a heating rate of 5 °C/min. The specimens were loaded at six temperatures, 200 °C, 400 °C, 600 °C, 800 °C, 1000 °C, and 1200 °C maintained for 60 minutes. The acoustic emission activity and some material characteristics were evaluated in a three-point bending test.

Influence of Recycled Construction Materials Aggregate on Mechanical and Physical Properties of Concrete

Influence of Recycled Construction Materials Aggregate on Mechanical and Physical Properties of Concrete