Cube Compressive Strength Research Articles

Experimental Studies on Strength Properties of M60 Concrete with Partial Replacement of Cement by GGBS and Fly Ash

Abstract: Among all the current construction materials, concrete occupies a unique position. Concrete is the most often utilised building material. Cement production emits CO2, which is harmful to the environment. One of the most crucial ingredients in concrete production is cement. Experiments were carried out to see how different percentages of Fly Ash and GGBS affected the mechanical qualities of M60 grade concrete. After 7, 14, and 28 days of curing, the compressive strength of concrete cubes with suggested replacement was determined. Compressive strength, split tensile strength, and flexural strength are all evaluated on the cubes, cylinders, and prisms. The primary goal of this study is to compare the fresh and hardened characteristics of M-60 grade control concrete with concrete prepared with varied ratios of fly ash and GGBS Keywords: GGBS, Fly Ash, Durability, Compressive Strength, Tensile Strength, Flexural Strength, Slum cone Test

Mechanical properties of hybrid fiber reinforced coral concrete

This paper investigated the effect of microfibers (carbon fibers and basalt fibers) and macrofibers (plastic steel fibers) on the mechanical properties of coral concrete. A total of 192 specimens were designed with carbon fibers (CFs), basalt fibers (BFs), and plastic steel fibers (PSFs) as variables. The compressive strength, splitting tensile strength, axial compressive strength, and elastic modulus of hybrid fiber-reinforced coral concrete were studied by testing. The results show that all three fibers can improve the mechanical properties of coral concrete. The microfiber major positively affects the stage before the macrocracks are formed, and the positive effect of macrofibers major works on the stage after the macrocracks are appeared. Hybrid addition of microfibers and macrofibers can further improve the mechanical properties. The cube compressive strength, splitting tensile strength, axial compressive strength, and elastic modulus can be improved by 11.2%, 25.5%, 14.1%, and 8.5%, respectively, when incorporating the optimum hybrid fiber dosages (CFs 0.15%, BFs 0.15%, and PSFs 4 kg/m3).

Evaluation of compressive strength using novel in situ test method

AbstractDouble shear test method (DSTM) proposed in the past is commonly used for the estimation of the in situ compressive strength of concrete. A novel in situ compressive testing method (IST), which can reduce core testing time from 2 to 3 days to 30 min using short cores tested in site is developed and proposed in this paper. The core samples with different diameters and lengths were tested using the in situ single shear test (IST) and then compared with DSTM. No significant difference exists in the core strength results obtained from the Student's t tests by IST and DSTM. A correction factor correlating the results obtained using IST methods was therefore provided. Experimental results indicate that an excellent correlation exists between concrete IST strength and cube compressive strength (10–60 MPa). Since no extraction of the core is needed, the specimens can be readily and quickly prepared in situ with less damage to the structure. The verification investigation shows that the IST can provide a more accurate estimate of in‐place cube strength than the core drilling method and can be performed easier than the core drilling method, with less time‐consuming than other methods.

Advanced materials management for Indian construction industry by application of statistical process control tools

This paper aims at exploring the applications of advanced Statistical Process Control (SPC) tool like Cumulative Sum (CUSUM) with V-mask for monitoring of advanced materials of construction industry like Ready Mixed Concrete (RMC). Quality of concrete produced by commercial RMC batching plants of Delhi and Ahmedabad, India were monitored by the application of CUSUM with V-mask. Primarily the 28-day cube compressive strength of the concrete were monitored with this tool. Collection of primary data included the different types of the grades of concrete, mix-design for the concrete produced and also the production procedures of commercial batching plants. The proposed SPC tool was used to analyze and detect whether the results of the compressive strength of the concrete were within the target design strength. If the results obtained were unsatisfactory, then a root cause analysis was carried out to find out the cause of the problem. Results during the investigations carried out during the root cause analysis revealed that the RMC plants were using more cement to reduce the producers’ risk of producing a concrete which may be rejected by the consumer. Usage of higher cement content is a wastage of resource and also it creates shrinkage cracks. It has been expected that about INR 8 million to 9 million per year may the potential cost savings by application of CUSUM technique with V-mask for monitoring the quality of the RMC produced by the commercial RMC plants.

Hysteretic Behavior on Asymmetrical Composite Joints with Concrete-Filled Steel Tube Columns and Unequal High Steel Beams

In order to acquire the hysteretic behavior of the asymmetrical composite joints with concrete-filled steel tube (CFST) columns and unequal high steel beams, 36 full-scale composite joints were designed, and the CFST hoop coefficient (ξ), axial compression ratio (n0), concrete cube compressive strength (fcuk), steel tube strength (fyk), beam, and column section size were taken as the main control parameters. Based on nonlinear constitutive models of concrete and the double broken-line stress-hardening constitutive model of steel, and by introducing the symmetric contact element and multi-point constraint (MPC), reduced-scale composite joints were simulated by ABAQUS software. By comparing with the test curves, the rationality of the modeling method was verified. The influence of various parameters on the seismic performance of the full-scale asymmetrical composite joints was investigated. The results show that with the increasing of fcuk, the peak load (Pmax) and ductility of the specimens gradually increased. With the increasing of n0, the Pmax of the specimens gradually increases firstly and then gradually decreases after reaching a peak point. The composite joints have good energy dissipation capacity and the characteristic of stiffness degradation. The oblique struts force mechanism in the full-scale asymmetrical composite joint domain is proposed. By introducing influence coefficients (ξ1 and ξ2), the expression of shear bearing capacity of composite joints is obtained by statistical regression, which can provide theoretical support for the seismic design of asymmetrical composite joints.

Experimental Study on Properties of Concrete Using Shredded Plastic Waste and M-Sand as Partial Replacement of Fine Aggregate

Disposal of large quantity of plastic causes land, water, and air pollution etc.., so a study is conducted to recycle the plastic in concrete. This work investigates about the replacement of natural aggregate with non-biodegradable plastic aggregate made up of mixed shredded plastic waste in concrete. Several tests are conducted such as compressive strength of cube, compressive strength of cylinder, flexural strength test of prism to identify the properties and behavior of concrete using shredded plastic aggregate. Replacement of fine aggregate weight by 0%, 5%, 10%, 15%, 20% with shredded plastic fine (PF) aggregate and manufactured sand (M-Sand). Totally 30 cubes, 30 cylinders and 30 prisms are casted to identify the compressive strength, cylindrical compressive strength, and flexural strength respectively. Casted specimens are tested at 7, 14 and 28 days. The identified results from concrete using shredded plastic aggregate are compared with conventional concrete. Result shows that initially there is increase in mechanical properties then there is reduction in mechanical properties due to addition of shredded plastic aggregate added concrete. This reduction in strength is mainly due to poor bond strength between cement and shredded plastic aggregate.

Size effect on compressive behaviors of waste fiber-reinforced recycled aggregate concrete

The compressive size effect of conventional concrete is well known, but there is limited knowledge of the fiber-reinforced recycled concrete. A total of 270 specimens with the different cube and prism sizes, water-cement ratios, compressive strength grades, the replacement rates of recycled aggregates, and volume fractions of waste fibers were tested until failure to study the size effect behaviors of waste fiber-reinforced recycled concrete subjected to axial compression. The results showed that as the replacement rate of recycled aggregates increases, the size effect degree of the cube and axial compressive strength increases. With the increase of the volume fraction of waste fibers, the size effect degree of compressive strength decreases first and then increases, with the optimum volume incorporation of 0.12%. The higher the strength grade of concrete is, the more obvious the size effect of strength is. For large-scale components, no incision correction of Bažant and Carpineri’s fractal size effect theory is more suitable for the analysis of the size effect of waste fiber recycled concrete. It is essential to understand the compression size effect of waste fiber-reinforced recycled concrete so that the laboratory investigation results can be applied to real full-scale structures subjected to compressive loading.

Predictive Models for Bond Strength of Reinforced Concrete with the Application of ANN

The bond strength of grip b/w steel and concrete can be defined as the resistant to separating concrete or mortar from the reinforced bar. This bond strength is the most critical characteristic of reinforced-cement concrete. Structural performance depends upon this characteristic, especially in the failure phase. Bond strength is primarily dependable on many variables that affect this attribute. These variables include the diameter of the reinforced steel bar, bond extent, length to diameter ratio, cube compressive strength, concrete cover, cover to dimeter ratio, volume fraction and most importantly, different temperatures. Up to 150°C, there is no such change in bond strength of reinforcement concrete, but when the temperature rises beyond 150°C, it starts to decreasegradually. We have collected experimental data from the internationally published record. This study will see the change in bond strength at these temperature variations i.e., 200°C, 400°C, and 600°C. This observational study will represent a soft computing tool, i.e., an Artificial Neural network (ANN), to predict and measure the grip strength between concrete and steel bar at elevated temperatures. The bond strength of reinforced concrete has been predicted by using ANN Models. Data set based upon the different factor that affects the bond strength has been used as input for generating ANN model & ultimate bond strength of reinforced concrete has been used as output during the development of the ANN model. This model was then prepared to predict bond strength and affected by many input features and recorded a linear regression analysis. The predicted result then confirmed the accuracy and high estimation capability of the model.

An Experimental Study on Geopolymer Concrete by Using Flyash, GGBS and Alccofine

In this study concentrated on the development of GPC by using industrial waste products such as fly ash, alccofine (1203) and GGBS. GPC is an advanced eco-friendly concrete manufactured by activating source minerals rich in alumina and silica by alkaline liquids to form aluminosilicates based on inorganic polymers. Where cement was complete replaced with mix proportion of 50% fly ash, 25% alccofine (1203) and 25% GGBS for different molarities (8M, 10M and 12M) of alkaline activators which is solving the problem of unsustainable usage of limestone and pollutant related to the manufacturing process of cement. The present paper reports the cube compressive strength, cylindrical split tensile strength and flexural strength of GPC and which is compared with M25 grade of control specimens. It was observed that the strength of GPC is increased than normal concrete as molarities increases of 8 M, 10M and 12M. The paper explains about the effectiveness of fly ash, alccofine (1203) and GGBS materials.

COMPRESSIVE STRENGTH BEHAVIOURS OF LAGOON–WATER CURED CEMENT-ALUMINIUM DROSS CONCRETE

This study investigates the compressive strengths of concrete cubes and reinforced columns cast with partial replacement of cement using 0- 25 wt.% Aluminum dross (AlDr) and cured in Lagoon water for 7-42days and 1-6 months respectively. The results indicated cubes with 5 wt.% AlDr, 10 wt. % AlDr and control possess strength of 15N/mm2,14.59N/mm2 and 13.48N/mm2 respectively at 28-day curing while at 42-day the results are 16.89N/mm2, 12.22N/mm2 and 16.96N/mm2 for control, 5 and 10 wt.% AlDr respectively. The 42-day compressive strength (79.48%) confirmed the performance at 28-day strength (75%). Control cube (74.6-95.5%) has higher crystallinity compared to cement (65.1-90.1%) and AlDr (62.4-74.0%) but at 15 wt.% AlDr concrete the crystallinity (78.1-96.2%) is superior with marginal crystal sizes variation (12.8-16.9). The strength (~9.5 N/mm2) with 10 wt. % AlDr column cured for 6 months was better than the control columns environment (~7 N/mm2) at 2-month.

Shear strength of plain concrete made of recycled low-strength concrete aggregates and natural aggregates

This paper reports the results of an experimental study of the shear strength of plain concrete made using recycled low-strength concrete coarse aggregates (RCA) and natural coarse aggregates (NCA). Ninety push-off specimens were cast and tested. Three types of coarse aggregates were used: recycled low-strength waste concrete, limestone, and gabbro. The other variable in the concrete was the water to cementitious materials ratio (w/cm), which varied from 0.31 to 0.72. The push-off shear strength (vpo), the cube compressive strength (fcu), and the shear failure surfaces were investigated. The results showed that recycled aggregates concrete (RAC) had lower push-off shear and compressive strengths relative to the natural aggregates concrete (NAC) of similar w/cm ratios. However, the relationship between vpo and fcu was similar for the NAC and the RAC. This indicates that the effects of using RCA on the shear strength can be accounted for indirectly by consideration of their effects on fcu. The tests also showed that failure surfaces were more smooth in the concrete with lower w/cm ratios. In addition, the use of RCA affected the failure surfaces slightly. Based on a linear-elastic finite element analysis, a relationship between the tensile cracking strength σcr and vpo for the push-off specimen was established. Consequently, the experimental results suggest that the equation σcr=0.43fcu can be used to relate the tensile strength to the compressive strength of concrete.

Assessment of mechanical properties and workability for polyethylene terephthalate fiber reinforced concrete

Many researchers have utilized recycled plastic trash to substitute aggregate in concrete for decades, and this document describes the technical properties of recycled plastic waste in detail. The resin impacts the concrete's new qualities, which affects the concrete's mechanical properties and durability. The inclusion of resin modifies the mechanical characteristics and strength of the concrete, according to current test results. Plastic fibers derived from plastic trash bottles were used to reinforce ordinary concrete in this investigation. The compressive strength of cubes and cylinders made of standard and fiber-reinforced concrete is determined in the laboratory. The experiments used concrete grades M25 and M30 and two geometric fibers with a volume ratio of 0.0% to 3.0%, cured for 28 days. This document establishes the relationship between compressive strength and cylindrical strength for conventional reinforced concrete and plastic fibers and compares it with standards.

Evaluation of strength parameters of ultra-fine flyash and nanosilica incorporated High-Performance Concrete

The effect of ultra-fine fly ash (UFA) and nanosilica on the strength properties of High-Performance Concrete are investigated in this study (HPC). Cement was replaced in varying batches with UFA at 0%, 10%, 20% and 30% by weight of cement. Nanosilica was added at a rate of 0 %, 1.5 %, 3.0 %and 4.5 %by weight of the binder. Water-to-binder ratios of 0.3, 0.325, 0.375, 0.4, and 0.425 were used in the mix design. All of the concrete mixes were evaluated for compressive strength at 7, 28, and 90 days, as well as split tensile and flexural strength at 7 and28 days. Conclusions were drawn by comparing the results with conventional concrete. The HPC with 10% UFA, 3.0% nanosilica, and 0.30 water-to-binder ratio had the best results, with compressive strength gains of 28.24 %, 28.11 %, and 31.89 % at7, 28, and 90 days, respectively. Tensile strength increased by 21.84 percent and 38.56 percent after seven and twenty-eight days, respectively, while flexural strength improved by 39.26 percent and 24.37 percent. Mathematical relationships between cube compressive strength and split tensile strength, as well as flexural strengths, were developed as a result of this research.

Design of High-Strength Concrete for Ready-Mixed Concrete Production

The high-strength concrete is a cement composite reaching high compressive strength, namely, pursuant to the legislation, higher than 60 MPa in the terms of cube compressive strength. The development of high-strength concretes exceeding 100 MPa is still an up-to-date issue and the production of these concretes is still limited only to a prefabrication. Contemporary construction industry and projecting activity have begun to focus on a construction of statically demanding buildings, which can include e.g. high-rise buildings. Such projecting often requires using of the state-of-the-art materials like cement composites with high mechanical parameters for construction of more subtle buildings. Within this article, the procedure of ready-mixed concretes development with the compressive strength around 100 MPa designed according to a project documentation for actual construction of high-rise building with the height up to 160 meters and 46 floors is described, together with the influence of the aggregate on the resulting composite strength.

Utilization of Quarry Dust as a Partial Replacement of Sand in Concrete Making

The use of crushed quarry dust as a partial replacement of river sand in concrete production was investigated in this study. This is expedient as quarry dust can be available at some locations with insufficient river sand for construction purposes. The use of quarry dust is also in concrete is also a measure necessary for improvement of concrete strength. River sand was replaced with quarry dust for different mix designs of concrete for 0% to 25% replacement levels with 5% intervals. The physical properties of river sand and quarry dust were tested and reported and the workability as well as compressive strengths of the concrete mixtures were also tested. It was observed that the slump values increased with increase in percentage replacement of sand with quarry dust. The compressive strength of cubes at 28 day curing for control mixture of 1:3:6 at 0% partial replacement of river sand with quarry dust was 12.6N/mm2 but compressive strengths of 21.5 N/mm2 and 26.0 N/mm2 were gotten for 1:2:4 concrete and 1:1.5:3 concrete respectively. As the quarry dust content increased to 25%, the 28day compressive strength increased to 13.58 N/mm2 and 21.57 N/mm2 for the 1:3:6 and 1:2:4 mixes respectively. Compressive strength values decreased to a value of 25.72N/mm2 for the 1:1.5:3 concrete mix. The maximum compressive strength values were reached at 20% quarry dust content at the age of 28 days for the three concrete grades investigated. The increase in compressive strength with inclusion of quarry dust was attributed to the higher specific gravity of quarry dust above river sand. The compressive strength of quarry dust concrete continued to increase with age for all the percentages of quarry dust contents. Quarry dust was recommended as a suitable partial replacement for river bed sand in concrete production.

Seismic Performance of Hybrid and Non-Hybrid Fiber-Reinforced Concrete Based Beam-Column Joint

Beam-column (BC) joints are the most crucial zones of structures wherein that region, the bond, and normal stresses are comparatively higher. In the present study, the seismic performance of the joint region has been improved with reinforcement with various fibers (polypropylene fiber and steel fiber). Tests are performed with various fiber types in the BC joints under a 100 kN capacity cyclic actuator. The output attributes considered are load, displacement, degradation in the stiffness, drift angle, and dissipation of energy in the BC joint. The specimens have also been computationally modeled and analyzed for static cases using ANSYS-v14 software. Static analysis procedure has been used to determine the key parameters like displacement, stress, strain, and forces in structural components due to the loads. Percentages of polypropylene fiber are varied between 0.15 - 0.50% and the steel fiber is kept constant at 0.75%, while the control specimen (CS) prepared with only normal concrete of mix M25 grade of concrete with characteristic cube compressive strength of 25 MPa without any fibers. Results indicate that the specimen having 0.25% polypropylene and 0.75% steel fiber exhibits better performance under reversed cyclic loading. Further, improvement in BC joints in terms of strength and ductility has been observed in presence of hybrid fibers.

Strength index analysis of concrete with large size recycled aggregate based on back propagation neural network

A back propagation (BP) neural network (NN) model was used to analyze the relationship between the cube compressive strength and various strength indicators of concrete with large-sized recycled aggregates (LSRA) (80 mm maximum size). Factors such as strength and replacement rate of recycled aggregates were used as input parameters to establish the neural network model. The BP-NN model was optimized by analyzing the influence and sensitivity of each parameter in the model. Then the mechanical properties of concrete with LSRA were predicted. Results showed that the strength of new concrete had a more significant impact on the strength of recycled concrete with LSRA, followed by the strength of old concrete. While considering all the factors, including the mechanical strength and the replacement ratio regarding the maximum utilization of RA, the 30% incorporation rate was suggested as an ideal incorporation rate.

Microbial-Induced Carbonate Precipitation Improves Physical and Structural Properties of Nanjing Ancient City Walls.

The preservation and restoration of heritage sites have always been of key focus in the field of cultural relics. Current restoration methods mainly involve physical or chemical techniques, which are in many cases intrusive, destructive, and irreversible. Hereby, we introduce a novel biological strategy (microbial-induced carbonate precipitation (MICP)) to repair natural and simulated surface cracks on six hundred years’ old wall bricks (part of the Nanjing City Min Dynasty ancient wall, China). X-ray micro computed tomography (X-ray micro-CT) was employed to non-destructively visualize the internal structure of the MICP-treated brick cubes. The results showed that MICP can effectively repair both natural and simulated cracks present on the brick’s surface. The compressive strength of the MICP-treated brick cubes was significantly higher than that of the untreated control cubes (33.56 ± 9.07 vs. 19.00 ± 1.98 kN, respectively). MICP significantly increased the softening coefficient and decreased the water absorption rate (p < 0.05), indicating that the water resistance of the wall bricks can be improved after treatment. The 3D images from X-ray micro-CT, a method that could non-destructively assess the internals of such cultural structures, showed that MICP can effectively repair ancient relics, promoting durability and limiting degradation without affecting the structure. X-ray diffraction analyses showed that MICP generates the same calcite form as that of original bricks, indicating that MICP filler is compatible with the ancient city wall brick. These findings are in line with the concept of contemporary heritage preservation.

Bearing Capacity of Hollow GFRP Pipe-Concrete-High Strength Steel Tube Composite Long Columns Under Eccentrical Compression Load

To investigate the bearing capacity of the hollow Glass Fiber Reinforced Polymer (GFRP) pipe-concrete-steel tube composite long columns subjected to eccentrical compression load, 33 hollow GFRP pipe-concrete-steel tube composite long columns have been designed. The slenderness ratio (λ), compressive strength of concrete cube (fcu), eccentricity (e) and so on are the main parameters. Based on constitutive models for steel, GFRP and confined concrete, numerical simulation of the hollow GFRP pipe-concrete-high strength steel tube composite long columns has been carried out by using software ABAQUS. The rationality of the constitutive models and modeling method has been verified by comparing the experimental and simulated load-displacement curves. The influence of different parameters on the mechanical behavior of this kind of column has been investigated. Results show that with the increasing of t1, t2 and fcu, the ultimate eccentrical compression bearing capacity of the specimen increases. With the increasing of e, the ultimate displacement of the specimens increases, while the ultimate eccentrical compression bearing capacity decreases. The eccentricity has a significant influence on the ultimate eccentrical compression bearing capacity. With the increasing of λ, the ultimate eccentrical compression bearing capacity of the specimens gradually decreases. The specimens suffer from ductile failure. The formula of the ultimate eccentrical compression bearing capacity of the composite columns is obtained by statistical regression. The study can provide theoretical support for the application of the composite columns in practical engineering.

Experimental Study of a New Concrete Admixture and Its Function in Filling and Reinforcing Granite Fissures

A concrete admixture with water retention and superhydrophobic properties was developed according to the high tensile strength, fissure resistance, and antiseepage requirements of concrete linings. Capillary water absorption, early-age anticracking, cube compressive strength, and splitting tensile tests were employed to study the effects of the new concrete admixture on the basic performance of concrete. On this basis, a triaxial compression test was conducted on granite fissures filled with concrete containing the admixture; the stress-strain and failure characteristics under different admixture dosages, confining pressures, and fracture widths were analyzed, and the reinforcement effect of the concrete with the admixture on the fractured rock mass was studied. The results show that the admixture can effectively improve the ability of concrete to resist water and fissures, and the concrete with the admixture significantly reinforced the fractured rock mass. Therefore, it can be widely applied in filling and reinforcing fractured rock masses.