Density Of Concrete Research Articles

The Use of Recycled Polyethylene in Water-Oil Emulsion for Lightweight Concrete

This study was to determine the suitability of recycled waste polyethylene (WPE) processed into water-oil emulsion for lightweight concrete applications. The processed WPE in the form of polyethylene emulsion (PE-e) is to promote physical interaction between the polymeric material and the cementitious matrix. The PE-e used was also to partially replace concrete mix composition by PE-e_1, PE-e_2.5, PE-e_5, and PE-e_10 percents for reference concrete and to introduce plasticity into the mechanical behaviour of the concrete. The PE was processed into PE-e to promote affinity for water, and this hydrophilicity was prominent in PE-e_1 and PE-e_2.5 percent concretes. Concretes with PE-e_1 and PE-e_2.5 percent formed good miscibility with the cementitious matrix. The density of the PE-e concrete decreased to 13.68% with 10% PE-e at 28 days. The replacement of mix constituents of PE-e_1, PE-e_2.5, and PE-e_5 percent induced elastic to plastic behaviour in the concrete coupled with low water absorption. The FTIR data showed characteristic peaks of 3378 cm-1, 1740 cm-1, and 1148 cm-1 in the PE-e. Using optical microscopy, it was shown that the PE particles were homogenously dispersed in the concrete matrix. The study shows the feasibility of using PE-e_1 percent to produce structural lightweight concrete and up to PE-e_10 percent for nonstructural applications mainly for light non-load-bearing partitions.

Improved Deflection Prediction Model for PSC Box Girder with Stay Cable System during Tensioning Phase

To improve the accuracy of deflection prediction for prestressed concrete (PSC) box-girder bridges with a stay cable system (SCS) during tensioning, this study employs the Latin hypercube sampling (LHS) technique to sample random variables affecting long-term deflection of the main girder. A long-term deflection randomness analysis model is established, and the shear stiffness degradation factor is included to quantify the contribution of diagonal web cracking to the main girder deflection. Uncertainty and sensitivity analysis are conducted for the Dongming Huanghe River Highway Bridge. An objective function is applied to select the optimal combination of random variables, and a modified model is established and verified for accuracy. Results show that diagonal web-cracking accounts for 8.8% of total deflection and cannot be ignored, and the prestressed tension control stress, creep uncertainty coefficient, and concrete density significantly impact long-term deflection. The modified model predicts deflection with greater accuracy than the mean value model.

Impact of coconut husk microcrystalline cellulose on the properties of geopolymer lightweight concrete

Geopolymer composite is an alternative to ordinary Portland cement. It has potential to avoid CO2 emissions to the atmosphere and to save raw materials during its manufacture. Flyash-based geopolymer concrete is altered by adding ground granulated bast-furnace slag (GGBS) to improve its fresh and hardened properties. Thermal ash aggregate is used as coarse aggregate to reduce geopolymer concrete density, improve strength, and conserve natural aggregate. Along with this matrix, coconut husk microcrystalline cellulose (MCC) is added to enhance its performance. In a M40 grade flyash and GGBS-based geopolymer concrete, MCC was used to replace fly ash at 1% to 5% levels. The geopolymer composites were tested for slump, compression, split tensile, water absorption, and acid resistance to determine the way coconut husk MCC interacts with lightweight concrete. An inclusion of 3% MCC with geopolymer composites improved 2% slump, 6% of compressive and split tensile strength. About 1.6% of water absorption was reduced in GPC matrix with 3% of MCC. Meanwhile 3% of MCC in geopolymer concrete improved, 4% of weight and 7% of strength under acid exposure. The research strongly supported utilizing MCC in geopolymer concrete to render it more sustainable and eco-friendlier.

Effect of Recycled Coarse Aggregates (RCA) on Geo-Polymer-Based Concrete

The construction industries are looking towards the production of environmentally friendly concrete, with the use of fewer natural resources, less energy, and minimum carbon dioxide emissions. For this reason, the geo-polymer concrete is one of the best options. The concrete produced with a polymerization process; a reaction between alkaline compounds containing alumina and silica; is called geo-polymer-based concrete. This study is focused on investigating the density and strength properties of geo-polymer concrete with Recycled Coarse Aggregates (RCA). Three mixes were designed with 0%, 50%, and 100% RCA with a fixed water-binder ratio equal to 0.4. The results revealed that the compressive, tensile, and flexural strength of geo-polymer-based concrete with RCA reduced and depended on the percentage of RCA used. The flexural performance of the concrete was observed better compared to compressive and tensile strength. However, the density of concrete is decreased by approximately 14% with the addition of RCA resulting in lighter concrete than the control mix.

Theoretical Ionizing Radiation Shielding Parameters of Thulium Doped Zinc Borotellurite Glass

Ionizing radiation is considered hazardous to human health but it is very crucial for many applications such as nuclear fuel processing and medical radiography. Glass has played a huge role as a shielding material for ionizing radiation in the application that requires line of sight. Nowadays, lead glass is commonly used in industry due to its properties of high density. However, lead toxicity can give harmful effects on humans’ health and the environment. As for concrete, it takes a lot of space, blocks the line of sight and the density of concrete may reduce due to prolonged exposure to radiation. To cater these problems, this study proposed a glass composition that is thulium doped zinc borotellurite glass. Thulium is used due to its potential such as resistance to corrosion and oxidation, good ductility and does not pose any environmental threat. In this study, Phy-X and WinXCom software is used. The main goal of this research is to study the theoretical radiation shielding parameters of thulium doped zinc borotellurite glass. Based on the results, it is found that the best glass sample is the sample composition with 5% thulium oxide whereby it has the highest value for mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), atomic cross section (ACS), electronic cross section (ECS) and effective atomic number (Zeff). The best glass sample with 5% thulium oxide also yields the results of the lowest half-value layer (HVL) and mean free path (MFP). Comparing the results of Phy-X and WinXCom, it is found that the deviation between the software is less than 5%. Also, when the results for each radiation shielding parameter of 5% thulium oxide are compared with other radiation shielding materials, significant results are found where the proposed glass sample provides better shielding against gamma radiation.

Durability and FTIR Characteristics of Sustainable Bacterial Concrete with Mineral Admixtures

The objective of this study is to optimize the concentrations of bacillus megaterium (BM), alccofine (AF), and silica fume (SF) in self-healing concrete while controlling the content of manufactured sand (M-sand). This research addresses the pressing need for sustainable alternatives to traditional cement as excessive energy consumption and environmental impacts continue challenging the construction industry. A novel “binary and ternary blended cementitious system” was developed, featuring twelve distinct mix proportions. M-sand was fully utilized as an acceptable aggregate substitute, with bacterial concentrations of (10–50)·105 cells/ml incorporated to mitigate crack formation. Cement was partially replaced with AF, and the M-sand content was adjusted from 0 to 20 % in 5 % increments. This study also uniquely evaluates the durability properties of the various cementitious systems, including water absorption, concrete density, porosity, long-term strength retention, and rapid chloride permeability – at intervals of 7, 14, and 28 days post-curing. Fourier transform-infrared spectroscopy (FTIR) was employed to analyze calcite precipitation, providing insights into the biochemical mechanisms. The results indicate that while SF demonstrates superior effectiveness compared to AF, combining both enhances durability compared to alternative mixes. The findings reveal that bacterial concrete incorporating zeolites can significantly improve structural strength and be a sustainable building material. Notably, incorporating additional cementitious materials with mineral admixtures increased strength by up to 10 % through optimized bacterial concentrations. The successful precipitation of calcium carbonate confirmed the beneficial properties of the bacterial agents, which are safe and non-toxic to the environment. Overall, this study contributes valuable knowledge on reducing cement usage and carbon dioxide emissions, positioning BM, alongside AF and SF, as a promising approach for environmentally friendly concrete solutions.

Evaluation and Analysis of Asphalt Concrete Density Based on Core Samples

Evaluation and Analysis of Asphalt Concrete Density Based on Core Samples

An Experimental Investigation of a High-Density Concrete with Waste Ceramic Tiles Used as an Aggregate

Abstract: The use of waste material as aggregates in civil engineering applications is beneficial and increasingly desirable because it reduces the environmental impact and economic cost of mining, processing, and transportation operations. Therefore, this study focused on establishing the effect of crushed tile on the compressive strength of concrete. In this research investigation, ceramic waste tile waste was substituted for natural coarse aggregate in concrete to varying degrees from (0, 10, 20, and 30%), and the M-20 graded concrete was used to produce high density concrete. After 3, 7, and 28 days of the curing process, few number of new concrete mould were casted and evaluated about the Compressive Strength and Split Tensile Strength. The findings of these results showed that 35% replacement of naturally made coarse aggregate with the ceramic tile aggregate which contributes the higher compressive strength to produce the high-density concrete in construction industry.

Mechanical properties, attenuation coefficient, and microstructure of ultra high-performance heavyweight concrete for radiation shielding applications

This paper explores the characteristics of ultra-high-performance heavyweight radiation shielding concrete by using many types of radiation-resistant aggregates. The experimental work is carried out in two groups, The first group contains six mixes that are prepared by using barite, basalt, and serpentine as heavyweight coarse aggregate, and the second group contains six mixes that are prepared by using the same percentages of coarse aggregate in the first group while partially replacing the fine aggregates with hematite. The main research aim is to study radiation absorption characteristics using 60Co sources that discharge 1.25 MeV photons. Linear attenuation coefficient, half-layer value, and tenth-layer value layers were assessed as radiation absorption characteristics. In addition, the hardened characteristics of all mixes like compressive, tensile, flexural strengths, and modulus of elasticity have been investigated, also, microstructure has been tested. Based on the results, The density of mixtures ranged between 2690 and 3080 kg/m3. The largest value of concrete density was recorded for barite with hematite. Although basalt with hematite gave the maximum compressive strength value of 155.8 MPa. Barite with hematite improved the radiation protection properties compared to basalt with sand by 20 % as the Linear attenuation, HVL, and TVL values became 0.173 cm−1, 4.01 cm, and 13.28 cm respectively.

Formation of Cellular Concrete Structures Based on Waste Glass and Liquid Glass

The use of waste in the production of building materials is one of the possible ways to solve problems related to the sustainable management of non-degradable waste and difficult-to-recycle secondary resources. In this paper, a method is proposed for the non-autoclave production of an ultra-lightweight cellular concrete based on Portland cement, glass waste and liquid glass. A mixture of sodium hexafluorosilicate and hydroxide is used as a hardening activator, an aluminum powder serves as a gas-forming agent. The setting and hardening of raw mixtures occurs under the action of exothermal heat release due to a complex of chemical reactions occurring in the system, and the resulting material does not require additional heat treatment. It is optimal to use two fractions of glass waste to achieve acceptable material strength: coarse crushed (fineness modulus Fm = 0.945) and finely ground (specific surface Ssp = 450–550 m2/kg) glass. Glass particles of the fine fraction of glass, along with Portland cement, participate in hydrolytic and structure-forming processes, while glass particles of the coarse fraction play the role of reinforcing filler. The influence of the dispersion of glass and the density of liquid glass on the density, porosity, strength, water absorption and water resistance of the resulting cellular material was determined. At an average density of cellular concrete in the dry state of 150–320 kg/m3, the following characteristics can be achieved: a compressive strength up to 2.0 MPa, bending strength up to 0.38 MPa, thermal conductivity coefficient of the material in the range 0.05–0.09 W/(K·m), and a maximum operating temperature of 800 °C. The proposed ultra-lightweight cellular concrete can be used as a non-combustible heat and sound insulation material, as well as a repairing composition; the cellular concrete blocks can be used as filling masonry and for the construction of non-bearing internal walls.

Elevated temperature properties of foam concrete: Experimental study, numerical simulation, and theoretical analysis

Foam concrete, as an inorganic cellular material possessing exceptional thermal insulation and fire resistance properties, emerges as a promising candidate for thermal insulation. To achieve a more precise evaluation of its performance under elevated temperatures, the present study comprehensively investigates the thermal characteristics of foam concrete with a combined experimental, numerical, and theoretical approach. Firstly, a high-temperature test is conducted to investigate the influence of temperature and foam concrete density on its macroscopic appearance and internal temperature distribution. Meanwhile, the thermal conductivity of foam concrete at various densities and temperatures is directly measured with a thermal conductivity analyzer. Subsequently, to acquire comprehensive specific heat and thermal conductivity parameters of foam concrete, with a numerical model established within ABAQUS, the genetic algorithm is applied to identify these thermal parameters based on the measurement data from the elevated temperature test. In addition, CT scanning and 3D reconstruction of foam concrete before and after exposure to elevated temperatures are utilized to extract pore characteristics. This facilitates the thermal conductivity calculation using theoretical models, enabling the determination of the thermal conductivity of foam concrete above 600 °C. Through a comparison of the experimental, numerical, and theoretical results, it is recommended to consider the variation of specific heat in three dehydration stages due to the observed notable dehydration. Due to the effect of cracks, the numerically determined thermal conductivity is slightly higher compared to the experimentally and theoretically determined thermal conductivity. Based on the analysis, an improved formula predicting the specific heat of foam concrete, and a formula determining the thermal conductivity of foam concrete subjected to elevated temperature are proposed.

Preparation and Compression Resistance of Lightweight Concrete Filled with Lightweight Calcium Carbonate Reinforced Expanded Polystyrene Foam.

Lightweight concrete is widely used in the construction industry due to its low density and high strength. In this paper, lightweight concrete was prepared by a simple two-step method. Firstly, the light calcium carbonate reinforced epoxy macrospheres (LCR-EMS) material was obtained by adhering calcium lighter carbonate powder to the expanded polystyrene foam spheres (EPS) material using the "balling method". In the second step, the LCR-EMS was mixed with water, cement, and the hollow glass microspheres (HGMS) material using the "molding method" to obtain lightweight concrete. The combination of macroscopic photographs and microscopic morphology shows that the LCR-EMS material itself is uniformly encapsulated and well bonded to the matrix. Test results show that the density of the lightweight concrete decreases with an increase in the volume fraction of stacked LCR-EMS, the diameter, and the proportion of HGMS in the matrix, but it decreases with a decrease in the number of layers of LCR-EMS. The compressive strength of lightweight concrete exhibits a completely opposite trend. When three layers of LCR-EMS were used as filler material, the density and compressive strength of the concrete were 1.246 g/cm3 and 8.19 MPa, respectively. The density and maximum compressive strength of lightweight concrete were 1.146 g/cm3 and 6.37 Mpa, respectively, when filled with 8-9 mm-2L-90 svol% of LCR-EMS and 40 wt% of HGMS in the matrix. Compared with lightweight concrete filled with 90% EPS, the density increased by 20% while the compressive strength increased by 300%.

Application of Sulfur-2,4-dinitrophenylhydrazine as Modifier for Producing an Advantageous Concrete

In this investigative endeavor, a novel concrete variety incorporating sulfur-2,4-dinitrophenylhydrazine modification was developed, and its diverse attributes were explored. This innovative concrete was produced using sulfur-2,4-dinitrophenylhydrazine modification and an array of components. The newly created sulfur-2,4-dinitrophenylhydrazine modifier was synthesized. The surface texture resulting from this modifier was examined using SEM and EDS techniques. The component ratios within concrete, chemical and physical traits derived from the sulfur-2,4-dinitrophenylhydrazine modifier, chemical and corrosion resistance of concrete, concrete stability against water absorption, concrete resilience against freezing, physical and mechanical properties, durability, elastic modulus, and thermal expansion coefficient of the examined sulfur-infused concrete were assessed. The acquired results also substantiated that the thermal expansion coefficient value for sulfur-2,4-dinitrophenylhydrazine modified concrete was 14.8×10-6/0C. The average deformation of the analyzed concrete was 0.0026-0.0051, indicating a superior deformation performance compared to conventional concretes. Concrete with smaller aggregate sizes exhibited greater density, specifically 2283 kg/m3. The concrete density decreased gradually with an increase in aggregate size. The stability of sulfur-2,4-dinitrophenylhydrazine modified concrete was remarkably high in various aggressive environments. EDS analysis revealed that carbon atoms constituted 56.63% of the total mass, while sulfur made up 33.91% of the total mass. The obtained SEM outcomes demonstrated that the sulfur-2,4-dinitrophenylhydrazine modifier exhibited a more porous structure, devoid of crystalline formations. The sulfur-2,4-dinitrophenylhydrazine modification experienced a single-stage thermal mass loss, with the mass loss events being endothermic in nature. The IR findings verified the presence of amino functional groups (connected melamine ring) and the establishment of polymer sulfur chains.

Pervious Concrete Made with Recycled Coarse Aggregate and Reinforced with Date Palm Leaves Fibers

This study considers 12 pervious concrete mixes incorporating 100% recycled coarse aggregate from old concrete demolition waste and containing various amounts of natural fine aggregate and date palm leaves fibers. First, the properties of the recycled aggregate in terms of their particle size distribution, abrasion resistance, crushing values, specific gravity and water absorption are obtained. Next, the pervious concrete density, compressive strength, tensile strength, permeability and porosity are determined by experimental testing following the relevant standards. The results are analyzed and compared to determine the influence of using recycled coarse aggregate in the mixtures and the impact of the amount of natural sand and volume fraction of the fibers on the mechanical properties, permeability and porosity of the concrete. Findings of the study showed that the use of recycled coarse aggregate in pervious concrete without fine aggregate reduced the compressive strength by 36% and tensile strength by 57%. Replacing 11.7% of the recycled coarse aggregate with natural sand and adding date palm leaves fibers in an amount equivalent to 0.64% volumetric content to such concrete helped increase the compressive strength by 16.2% and tensile strength by 3.2% above the corresponding strengths of the control mix. There is a clear relationship between permeability and porosity due to their correlation with the density of pervious concrete, and the effect of porosity on tensile strength is more influential than it is on the compressive strength. An equation that can predict the tensile strength of pervious concrete from the compressive strength is proposed, as a function of the natural fine aggregate fraction of the coarse aggregate and volumetric content of natural fibers. Results of the research confirm the feasibility of using recycled aggregate in pervious concrete mixes and the positive impact of natural fibers on the mechanical properties.

Investigations on Strength and Durability Properties of Recycle Aggregate and Fly Ash in Concrete

In this investigative study the Natural Coarse Aggregate (NCA) were put back with Recycled Course Aggregate (RCA) at peculiar proportions, the mechanical performance and durability properties of concrete are examined. The inclusion of fly ash (FA) is also introduced as stand–in of Cement. The present investigation aims to determine the effect of RCA as an stand-in material to NCA and to analyze the fresh properties like workability, density and hardened properties like Compressive Strength, Flexure Strength, Split Tensile Strength and durability properties like Water permeability and Sorptivity. Mix is formulated for water cement ratio 0.40. The specimens were casted of replacing virgin aggregate with RCA by 10% and 20%, and cement with FA by 10%, 20% and 30%. All the specimens are cured for 7 and 28 days as per requirement later they are tested. The acquired data are then compared between the strength of NCA of concrete and the proportion of RCA and FA. The outcome view is in such a way that the workability of concrete will decline as the replacement of RCA increases, by which it should limited to a fixed percentage (10% or 20%). The density of concrete is not altered by the put back of FA, but raise in percentage of RCA replacement could alter the density of concrete. In case of Compressive, Flexure and Split tensile strength of concrete the optimum strength obtained for 10% FA and 10% RCA for 7 and 28 days was similar to that of 100% NCA and 0% FA and durability studies also gave the optimum results for the same replacement.

The Utilization of Silica Fume in Mortar Mixed with Rubber Crumb

This study looks closely at how rubber crumbs and additives might improve the mechanical properties of mortar concrete. It is focused to help the concrete industry transition this form of mortar concrete from a research laboratory level to a more useful usage. On the compressive strength, density, and water absorption of mortar concrete, the effects of various mixing techniques, mechanical which was before mostly on crumb rubber, and the use of fiber additions have been investigated. Mixing duration and order were two factors in the mixing technique. The replacement of fine aggregate with rubber crumb in the mortar was conducted from 0% (control sample), 5%, 10%, and 15% with fixed 5% of silica fume (replaced cement amount). A size of 50mm x 50mm x 50mm was used as a designing size cube sample in the current study. All blends should be subjected to a slump test before being used to determine the combination's level of durability. The water absorption and density value showed a good result giving benefits and advantages on increases of crumb rubber amount. However, compressive strength decreased when the amount of crumb rubber increased. In the application of roof tiles, lower density values provide an advantage for workability during installation.

Effect of temperature on thermal properties and residual strength of coal gangue concrete

Key factors for assessing the high-temperature resistance of coal gangue concrete are high-temperature residual strength and thermal properties. The high-temperature residual strength, high-temperature thermal conductivity, high-temperature specific heat capacity, and high-temperature density of concrete with various coal gangue coarse aggregate replacement ratios were tested using experimental methods in this paper to study the high-temperature resistance of coal gangue concrete. Thermal density and high-temperature residual strength tests took into account influencing factors like the water-cement ratio (0.50, 0.45, 0.40), aggregate replacement ratio (0, 25 %, 50 %, 75 %, 100 %), and temperature variation (room temperature, 200 °C，300 °C，400 °C，500 °C，600 °C，700 °C，800 °C), while thermal properties tests considered the effects of various coarse aggregate replacement ratios and temperatures. The study showed that when the temperature rises, coal gangue concrete's thermal density falls, mass loss rises, residual strength declines, thermal conductivity rises, and its specific heat capacity fluctuates. At temperatures between 20 °C and 400 °C, concrete's residual strength decreases with an increase in the coal gangue coarse aggregate replacement ratio, while thermal conductivity and specific heat capacity increase. At temperatures between 500 °C and 800 °C, however, concrete's residual strength slightly improves with an increased coal gangue coarse aggregate replacement ratio, while mass loss changes more. The research finally provides the formulae for calculating the high-temperature residual strength and thermal properties of coal gangue concrete based on the test results.

Utilization of waste foundry sand and fly ash in the production of steel fibre reinforced concrete

As the main raw materials for concrete preparation, natural sand and cement are in increasing demand. Meanwhile, the large accumulation of waste foundry sand (WFS) and fly ash (FA) seriously pollutes the environment. The research on the application of waste materials in concrete preparation has become a hotspot for scholars. This study attempts to respectively use WFS and FA to substitute natural sand and cement in the preparation of steel fibre reinforced concrete (SFRC). 3-factor, 3-level orthogonal experiment was designed, and the study variables include the WFS substitution rate (20%, 40%, and 60%), FA substitution rate (10%, 20%, and 30%), and SF content (1%, 2%, and 3%). The workability, dry density and mechanical properties of concrete were tested and discussed. Range analysis and variance analysis were used to analyse the effect of various factors on the different properties of concrete. Efficacy coefficient method was used to specifically determine the optimum substitution rate of waste materials for raw materials. Additionally, microanalysis was carried out to investigate the influencing mechanism of waste materials on the properties of concrete. It was observed that the workability of concrete deteriorated with the addition of waste materials, while the change of mechanical properties closely correlated with the content of waste materials. The workability and compressive strength were most significantly affected by the WFS content, while the density, tensile strength, flexural strength and elastic modulus were most significantly affected by the SF content. The mechanical properties of concrete were optimum at 34%, 20% and 2.3% of WFS, FA and SF content respectively. In this case, the compressive strength, split tensile strength, flexural strength and elastic modulus increase by 28.8%, 33.5%, 33.8% and 17.7% respectively compared to the control concrete. Microanalysis proved that moderate amount of WFS and FA could increase the beneficial pores, decrease the harmful pores, and reduce the porosity of concrete, but excessive WFS (60%) and FA (30%) would inhibit the hydration process and enlarge the porosity of concrete. This study demonstrates the feasibility of the application of WFS and FA in SFRC preparation, contributing to overcoming the pollution of waste material accumulation and alleviating the shortage of natural resources.

Research on the bearing capacity of foam concrete wall materials in green buildings

This study fabricated a combined wall with the help of a lightweight steel structural wall skeleton and foam concrete (FC) and designed four sets of strain experiments for walls with different FC densities and steel contents. In the displacement results, the higher the density of FC, the higher the load-bearing capacity. When the density of FC is 1000 and 1600 kg/m3, the wall will lose its load-carrying capacity after a maximum load of 80 and 90 kN, respectively. The greater the axial compression ratio of the sample, the greater the shear capacity of the combined wall. When the displacement distance is 30 mm, the maximum load is 162, 110, 94 and 85 kN when the shear span ratio is 1.0, 2.0, 3.0 and 4.0, respectively, and the load-carrying capacity decreases with the increase in the shear span ratio. Moreover, compared with the shear span ratio of 1.0, the load-carrying capacity decreases by 23, 41 and 51% successively. The maximum loads of the combined walls are 88, 79, 81 and 62 kN when the densities are 800, 1000, 1200 and 1600 kg/m3, respectively, and 75, 80, 81, 94 and 101 kN when the steel content ratios are 0.5, 1.0, 1.5, 2.0 and 2.5%, respectively.

The performance of Strengthened Lightweight RC Beams with different Techniques upon Exposure to Fire

Introduction: Reinforced concrete beams are used in a wide range of applications. In addition, reducing the weight of the concrete used increases the advantages of the beams. The main objective of this work is to study the performance of structurally strengthened lightweight reinforced concrete beams with different techniques with or without exposure to fire under concentric load and the efficacy of the fire protection system. Methods: The experimental specimens included eight half-scale tested rectangle beams with typical dimensions of 300 mm depth, 1700 mm total length, 150 mm total width, 50 mm cover, and 1500 mm span. The density of the lightweight polystyrene foam concrete was 1820kg/m3. The main parameters were fire resistance, different types of strengthening material for lightweight concrete beams, shape of the ferrocement layer on the lightweight concrete surface, and ferrocement thickness. Results: The results were analyzed in terms of crack patterns, failure modes, load deflection, load-strain behavior, stiffness, ductility, deformability, and absorbed energy. Conclusion: From the analysis of the results, the strength of LWC beams increased the strength and stiffness of the tested beam, and the fire protection system was found effective in protecting CFRP limitation from deterioration. In a theoretical study, the conservatism degree for calculating the maximum allowable flexure force was evaluated according to the ECP203, ACI-318, and BS-8110 codes.