Cube Compressive Strength Research Articles

Optimization of Partial Replacement of Fly Ash with Cement and Fine Aggregate with Eco Sand in Normal Concrete

Eco sand is a very fine particle, which is a by-product from the cement manufacturing industry by semi-wet process and it can be a good alternative for natural river sand. Due to its very finely powdered crystalline silica particles present in that which can replace up to 50% of conventional sand usage in concrete and mortars. It can be used in the concrete by replacement of fine aggregates by a certain percentage which gives much more efficiency. In this paper, the hardened properties like cube compressive strength, cylinder split tensile strength, and prism flexural strength are studied with various replacements cement with fly ash like 0 % and 30% and sand with eco sand-like 0%,30%,40%,50% and 60%. The results are compared with conventional concrete specimens. Experimental results also show that the hardened properties of concrete are increased by a certain amount when compared with the normal placed concrete specimens. During the study Due to replacement of fine aggregate with eco sand for workability conditions by some amount of chemical admixtures have been added.

Use of Glass Dust to Improve Concrete Strength on Offshore Platform Installations

The primary aim of this study is to investigate the influence of using glass dust as an additional in conventional concrete material on the properties of fresh and hardened concrete. Soil pollution happen when non-biodegradable materials disposed into land. However, the used of this non- biodegradable can do wonder for construction purposes. This is due to the non- biodegradable materials which cannot be broken down to simple organic molecules by micro-organisms. Glass dust is one of the example of non- biodegradable. Nowadays, the used of this dust becoming more popular due to its properties. In this study, the glass dust which consist of silica has being used as an additional ingredients to concrete cement. The concentrations of the glass has being varies to determine the mechanical properties e.g. compressive strength of M35 grade concrete. The variation of glass dust are from 10, 20 and 30%. The compressive strength of concrete cubes is tested after 7 and 14 days. The outcomes of the study are presented in tables and graphs.

Mechanical performance of green concrete produced with untreated coal waste aggregates

Recently, researchers have tried to find ways to reduce the negative effects of untreated coal wastes (UCW) on the ecosystem of the region. Recycling untreated coal wastes can however be identified as a practical solution in producing concrete aggregates. The present study investigates the mechanical properties of green concrete having untreated coal wastes. A total of eleven mix designs with different contents of untreated coal waste as aggregates were prepared and the cube, cylinder and prism compressive, tensile and flexural strengths as well as the elastic modulus of specimens were determined. The results revealed that untreated coal waste particles can potentially be reused in manufacturing concrete aggregates. It was also confirmed that selecting an appropriate amount of replacement can contribute to the property improvement of concrete, also suggesting an environmental solution to reducing untreated coal wastes. Therefore, replacing 5% of the aggregate with untreated coal wastes instead of sand and gravel, the mechanical properties increased. On average, in sand and gravel replacement compressive and flexural strength increased about 3–7% and 5–8%, respectively.

Effect of Stone Dust on the Mechanical and Microstructural Properties of Opc Based Concrete Subjected To Acid Exposure

A separate approach of sustainable development is to make the structures durable. More durable structures need to be replaced less frequently and will reduce the need for cement. Such increase in durability can be achieved by choosing appropriate mix designs and selecting suitable aggregates and admixtures. In this experiment sand (fine aggregate) is partially replaced by stone dust to make the concrete mix sustainable in nature. This study also investigates the durability of different types of concrete in acid exposure. Cube compressive strengths of different mixes have been compared to see how the concrete strength differs from original mixes. In addition different types of non-destructive tests such as ultrasonic pulse velocity test, rebound hammer test and half-cell potential tests have also been performed on the concrete samples for better analysis of their strength and durability characteristics. Specimens were analysed through the Scanning Electron Microscope to understand the microstructural changes of concrete samples. Energy dispersion X-ray analysis was also done to understand the changes in the nature of the hydration products of some specimen.

Factors Affecting Compressive Strength Development in Alkali-activated Slag Concrete

Studies show that the production and use of ordinary Portland cement (OPC) is responsible for more than 5% of the global CO2 emission. Alkali-activated slag (AAS) has been studied for decades as potential alternative to OPC. Engineers are interested in understanding and quantifying the fresh properties, mechanical properties, and durability of concrete made used AAS as sole binder. This paper reviews some of the literature highlighting the factors affecting compressive strength development in AAS slag. These include water-binder-ratio, temperature, humidity, and amount of Na2O, molarity of the alkaline activator solution, and type of alkaline activator. For instance, certain studies reported that AAS concrete activated using sodium silicate solution (water-glass) produce higher 7-day and 28-day compressive strength compared to similar concrete that use 100% OPC, concrete activated using sodium hydroxide (NaOH), or concrete activated using potassium hydroxide (KOH). When NaOH is used as activator, mechanical properties of concrete improved with increase in molarity of the alkaline activator solution. Compressive strength of concrete cubes increases with increase in the amount of Na2O supplied by the activator solution but to an optimum beyond which further increase in Na2O results in decrease in compressive strength. However, the optimum amount of Na2O, often reported as percentage of total slag content, varied from one study to another, probably dependent on the type of activator used as well as the water-to-binder (w/b) ratio.

THEORETICAL INVESTIGATION ON NORMAL SECTION FLEXURAL CAPACITY OF UHPC BEAMS

The relationships among peak compressive strain, cube compressive strength, elastic modulus, and axial compressive strength were established respectively based on 64 groups of Ultra High Performance Concrete (UHPC) compressive test data. The equivalent tensile strength of UHPC in the tensile zone was deduced through the mechanics of composite materials. Based on the plane section assumption, the formula for calculating normal-section flexural capacity of UHPC beams and the parameters of an equivalent rectangular stress block of UHPC in the compressive zone were deduced and the equivalent rectangular strength was calculated with the UHPC compressive constitutive relationship. Based on the data of 28 test beams, the feasibility of calculating the flexural capacity and the parameters of equivalent rectangular stress block was verified. The results show that the parameters of an equivalent rectangular stress block are reasonable and the calculated results of the normal-section flexural capacity of UHPC beams are in a good agreement with the experimental ones.

The Effect of the Presence of Ferric Iron in Water used for the Production of Concrete on Its Compressive Strength

This study examined the effect of ferric iron inherent in mixing water on the compressive strength of concrete. Portland Limestone Cement was considered in the production of the 150mm concrete cube samples. Dirt free river sand and crushed stone with maximum size of 14mm was used as fine and coarse aggregate respectively. The water samples used for the study were sourced from the following locations as stated: Sample 1: Niger Delta University Portable water at Niger Delta University Campus, Wilberforce Island (labelled P1). Sample2: Raw water from borehole at Niger Delta University Campus, Wilberforce Island and allowed to oxidized about 3 hours. Sample 3: Raw water from borehole at Amassoma in southern Ijaw Local Area, Bayelsa state and allowed to oxidized for about 3 hours. Sample 4: Oxidized water from Ogobiri in Sagbama Local Area, Bayelsa state. Sample 5: Oxidized water from Azikoro in Yenagoa Local Area, Bayelsa state. 150mm x 150mm concrete cubes samples were prepared with the various water samples stated above. A mix ratio of 1:11/2:3 was used for this experimental study. The samples were cured in accordance with BS EN 12390-2. Compressive strength values were determined for all specimens by means of a compression testing machine. Samples were tested to failure at 7, 14, 21 and 28days. The concrete compressive strengths test results for 7, 14, 21, and 28 days for sample 1 was 24.22 N/mm2, 27.63 N/mm2, 34.04 N/mm2 and 34.59N/mm2. For sample 2 was 18.79 N/mm2, 23.55 N/mm2, 27.30 N/mm2 and 28.59N/mm2, for sample 3 was 21.12 N/mm2, 22.81 N/mm2, 25.19 N/mm2 and 26.56N/mm2, for sample 4 was 19.80N/mm2, 22.71N/mm2, 26.80N/mm2 and 27.40N/mm2and for sample was 20.89N/mm2, 21.88 N/mm2, 26.20 N/mm2 and 27.30N/mm2respectively. The test results, show a noticeable decrease in compressive strength of concrete cubes cast with water that contained ferric iron when compared with water free from ferric iron. It was concluded that Ferric iron as impurities in mixing water have significant effect on the strength of concrete.

Effect of the Presence of Ferric Iron in Water used for the Production of Concrete on Its Compressive Strength

This study examined the effect of ferric iron inherent in mixing water on the compressive strength of concrete. Portland Limestone Cement was considered in the production of the 150mm concrete cube samples. Dirt free river sand and crushed stone with maximum size of 14mm was used as fine and coarse aggregate respectively. The water samples used for the study were sourced from the following locations as stated: Sample 1: Niger Delta University Portable water at Niger Delta University Campus, Wilberforce Island (labelled P1). Sample2: Raw water from borehole at Niger Delta University Campus, Wilberforce Island and allowed to oxidized about 3 hours. Sample 3: Raw water from borehole at Amassoma in southern Ijaw Local Area, Bayelsa state and allowed to oxidized for about 3 hours. Sample 4: Oxidized water from Ogobiri in Sagbama Local Area, Bayelsa state. Sample 5: Oxidized water from Azikoro in Yenagoa Local Area, Bayelsa state. 150mm x 150mm concrete cubes samples were prepared with the various water samples stated above. A mix ratio of 1:11/2:3 was used for this experimental study. The samples were cured in accordance with BS EN 12390-2. Compressive strength values were determined for all specimens by means of a compression testing machine. Samples were tested to failure at 7, 14, 21 and 28days. The concrete compressive strengths test results for 7, 14, 21, and 28 days for sample 1 was 24.22 N/mm2, 27.63 N/mm2, 34.04 N/mm2 and 34.59N/mm2. For sample 2 was 18.79 N/mm2, 23.55 N/mm2, 27.30 N/mm2 and 28.59N/mm2, for sample 3 was 21.12 N/mm2, 22.81 N/mm2, 25.19 N/mm2 and 26.56N/mm2, for sample 4 was 19.80N/mm2, 22.71N/mm2, 26.80N/mm2 and 27.40N/mm2and for sample was 20.89N/mm2, 21.88 N/mm2, 26.20 N/mm2 and 27.30N/mm2respectively. The test results, show a noticeable decrease in compressive strength of concrete cubes cast with water that contained ferric iron when compared with water free from ferric iron. It was concluded that Ferric iron as impurities in mixing water have significant effect on the strength of concrete.

Response of ultra-high performance cementitious composites filled steel tube (UHPCC-FST) subjected to low-velocity impact

Abstract This paper presents a combined experimental and numerical study on the transverse impact behavior of ultra-high performance cementitious composites filled steel tube (UHPCC-FST). UHPCC-FSTs were firstly fabricated by preparing the UHPCC with the cube compressive strength of 141.5 MPa. Then three specimens were tested in a drop-hammer impact device, and the impact force- and deflection-time histories of specimens under different release heights (5.0, 8.0 and 11.0 m) of the drop hammer were obtained and discussed. Furthermore, by using the commercial finite element (FE) program Hypermesh/LS-DYNA, a FE model was established to predict the impact behavior of UHPCC-FST. K&C constitutive model for concrete was adopted, and the corresponding model parameters for UHPCC were calibrated based on a series of test data (static compressive and direct tensile tests, dynamic compressive and tensile tests, triaxial compressive test, fly plate impact test), which were then validated by the present and existing drop hammer tests.

Research on Alternative to Replace Natural Sand in Cement Stabilized Rammed Earth Blocks

Natural Sand, which is being used extensively for all types of construction activities, is getting scarce now and many researchers have been put to task of testing other materials like manufactured sand for their usability in civil works. Present study aims at using the locally available soil for producing earth blocks. The materials like Auto aerated clay waste, manufactured sand are used in different proportions to see the possibility as a replacement for natural sand. Both the materials were used in proportion range of 35-65% along with 8% cement as a stabilizing agent. The cube compressive strength test was performed on soaked samples after 7 days and 28 days. It has been concluded from the result that the manufactured sand is cheap alternative material to replace natural sand

Potential use of small-diameter concrete cores for in situ compressive strength assessment

This paper examines the potential use of small-diameter cores (D < 100 mm), for estimating the in situ cube strength of concrete. The assessment is based on systematic analysis and evaluation of data sourced from published work since 1961, by 243 researchers working at 128 institutions in 32 countries, that yielded a matrix of 32 953 data points. The effects of core diameter (D), length to diameter ratio (L/D) and core diameter to maximum aggregate size (A) ratio (D/A) formed the main basis of the analysis. It is shown that there appears to be no technical justification for having requirements that limit D to 100 mm and/or D/A ≥ 3. Conversion factors are proposed for estimating, from the test results of small cores, the strength of cores having D = 100 mm and L/D between 1·0 and 1·2, which is currently the required size of cores to estimate the in situ compressive cube strength of concrete in the UK. It is shown that, in complying with the test data variability requirement, damage to structural elements through the coring can be reduced by adopting the use of small-diameter cores, down to 25 mm, where the damage is 10% that of 100 mm dia. cores.

Evaluating the Application of Reinforcement Correction Factor for Concrete Core Testing

This study investigates the reinforcement correction factor of concrete core in more detail to prepare appropriate outlines for interpretation of results. This investigation aims to minimize uncertainties involved to carry out the more realistic condition assessment of suspect buildings before taking up retrofitting/strengthening measures. For this purpose, an extensive experimental program including different concrete strength level, moisture condition, core size, length-to-diameter (L/D) ratio of core and steel bar size with various configurations was under taken. The effect of variation of foregoing parameters on the ratio of average compressive strength of cores containing steel bars to that of corresponding plain specimens was probed. The results show that the correction factors are highly dependent on the values of volume percentage and position of reinforcing bars in the core, which are extremely interrelated. Hence, the experimental results do not show a good agreement with the provisions by the British Standard 6089 and Concrete Society Report No.11. Therefore, a statistical analysis on the prediction of cube compressive strength using linear and nonlinear regression models is accomplished. The results showed that regression models have great ability as a feasible tool for prediction of compressive strength on the basis of core testing in the presence of steel bars. However, the most accurate results obtained by nonlinear equations in comparison with linear models.

Strength Conversion Factors for Concrete Based On Specimen Geometry, Aggregate Size and Direction of Loading

The main goal of this study is to find out the effect of effect of specimen shape and size, aggregate size and directions of loading and placement on the compressive strength of M20, M40, M60 and M80 grades of concrete. During the experimental study, different shaped and sized concrete specimens of different concrete mix designs were tested for compressive strength at 28 days. For casting the concrete samples, totally four different moulds were utilized, which were two different sizes of cubes and two different sizes of cylinders. The cubic moulds were 100 and 150 mm. The cylindrical moulds were 150×300 and 100×200 mm. So the relationship between size and shape effect on compressive strength of concrete samples is evaluated. Casted cubes and cylinders are tested for the compressive strength under axial compression on completion of 28 days as per IS: 516-1999.In this study, the effect of specimen sizes, specimen shapes, and placement directions on concrete compressive strengths for various grades widely used is evaluated. In addition, correlations between compressive strengths with size, shape, and placement direction of the specimen are investigated. It was found that with the increase of the size of the concrete specimen, compressive strength tends to decrease. The effect of grade of concrete on the shape effectof the compressive strength decreases as the specimen size increases regardless of strength level. Conversion factors of 0.80 to 0.90 were suggested for converting compressive strength of cylinders to compressive strength of cubes. For cubes, when the placement direction is parallel to the loading direction, the compressive strength is higher than the normal case. As aggregate size increases, compressive strength is found to be increasing.

Estimating moment capacity of ferrocement members using self-evolving network

In this paper, an empirical model based on self-evolving neural network is proposed for predicting the flexural behavior of ferrocement elements. The model is meant to serve as a simple but reliable tool for estimating the moment capacity of ferrocement members. The proposed model is trained and validated using experimental data obtained from the literature. The data consists of information regarding flexural tests on ferrocement specimens which include moment capacity and cross-sectional dimensions of specimens, concrete cube compressive strength, tensile strength and volume fraction of wire mesh. Comparisons of predictions of the proposed models with experimental data indicated that the models are capable of accurately estimating the moment capacity of ferrocement members. The proposed models also make better predictions compared to methods such as the plastic analysis method and the mechanism approach. Further comparisons with other data mining techniques including the back-propagation network, the adaptive spline, and the Kriging regression models indicated that the proposed models are superior in terms prediction accuracy despite being much simpler models. The performance of the proposed models was also found to be comparable to the GEP-based surrogate model.

Development and mechanical behaviour of ultra-high-performance seawater sea-sand concrete

Ultra-high-performance concrete is typically defined as an advanced cementitious material that has a compressive strength of over 150 MPa and superior durability. This article presents the development of a new type of ultra-high-performance concrete, namely, ultra-high-performance seawater sea-sand concrete. The development of ultra-high-performance seawater sea-sand concrete addresses the challenges associated with the shortage of freshwater, river-sand and coarse aggregate in producing concrete for a marine construction project. When used together with corrosion-resistant fibre-reinforced polymer composites, the durability of the resulting structures (i.e. hybrid fibre-reinforced polymer–ultra-high-performance seawater sea-sand concrete structures) in a harsh environment can be expected to be outstanding. The ultra-high strength of ultra-high-performance seawater sea-sand concrete and the unique characteristics of fibre-reinforced polymer composites also offer tremendous opportunities for optimization towards new forms of high-performance structures. An experimental study is presented in this article to demonstrate the concept and feasibility of ultra-high-performance seawater sea-sand concrete: ultra-high-performance seawater sea-sand concrete samples with a 28-day cube compressive strength of over 180 MPa were successfully produced; the samples were made of seawater and sea-sand, but without steel fibres, and were cured at room temperature. The experimental programme also examined the effects of a number of relevant variables, including the types of sand, mixing water and curing water, among other parameters. The mini-slump spread, compressive strength and stress–strain curve of the specimens were measured to clarify the effects of experimental variables. The test results show that the use of seawater and sea-sand leads to a slight decrease in workability, density and modulus of elasticity; it is also likely to slightly increase the early strength but to slightly decrease the strengths at 7 days and above. Compared with freshwater curing, the seawater curing method results in a slight decrease in elastic modulus and compressive strength.

AAM for Structure Beams and Analysis of Beam without Shear Reinforcement

Advances in technology and sustainability requirements create substantial demand for material research. In construction industry, possibilities of innovation of concrete are opened by using recipes based on new activation methods, where alkaline activated composites can be included. This article focuses on this area where the results of the recipe verified under industrial conditions are presented, and the way of processing is significantly different from the laboratory conditions. The aim of the article is to present the material properties and differences of alkali activated specimens that are compared with series of common concrete material properties based on composition from the same aggregate material base. It was found that the most significant differences are the modulus of elasticity. In both of the recipes, the same design cube compressive strength is used. The article presented also experiment and nonlinear analysis of the alkali-activated beam without shear reinforcement, which was used to study the mechanism of damage and collapse of AAM beam. Nonlinear analysis was used thanks to complex knowledge of material properties. Numerical modelling uses the ATENA software. Test of small structural element is complemented by an advanced crack detection diagnosis with the use of acoustic emission.

Compressive strength of geopolymeric cubes produced from solid wastes of Alum Industry and Drinking Water Treatment Plants

In this work, geopolymer is produced from two by-products waste as an alternative environmentally green construction and building materials without using Ordinary Portland Cement (OPC). Water Treatment Sludge (WTS) from Marg Drinking Water Treatment Plants in Cairo and De-Aluminated Kaolin (DAK) from Egyptian Company for Aluminum Sulfate were used in this study. Sodium hydroxide (NaOH)solution was used as an alkaline activator. The effect of the various influential factors on the compressive strengths of WTS/DAK geopolymer was investigated. These factors are mixing ingredient (WTS/DAK) ratios and amounts of NaOH of different normality. The mineralogical and chemical compositions of the WTS/DAK wastes were obtained using X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) analyses. Results show that the optimum ingredients providing maximum strength are the Na2O/SiO2 ratio of 0.56 and WTS/DAK ratio of 30:70. The development of compressive strengths over curing time of WTS/DAK geopolymer samples at optimum ingredients (30:70 WTS/DAK, 60 g NaOH 10 N and 70 oC for 72 hours). The compressive strength of WTS/DAK geopolymer gives 17 MPa after 7 days and increased to the maximum strength of 22 MPa at 28 days. The compressive strengths obtained to comply with the Egyptian Industrial Standards. Moreover, the WTS that traditionally disposed into landfills or drainage canals can be used sustainably in developing cement-free geopolymers with economic and environmental significance.

Measurement of acoustic emission at fibre reinforcement concrete slab with subsoil

The paper deals with the possibility of using the acoustic emission (AE) measurement for the identification of cracks and failure in fibre concrete slabs in interaction with subsoil. In this specific task it is not possible to check visually cracking on the slab bottom surface. The research task included an experimental load test of a slab and supplemented laboratory testing to determine the mechanical properties of fibre concrete. The concrete used has a dosage of 25 kg/m3 fibres. Laboratory tests included cube and cylindrical compressive strength, flexural strength and split tensile strength. Homogeneity of the concrete mixture, i.e. uniform distribution of the fibres, was proven with testing of the split tensile strength both evenly and perpendicularly to the direction of filling the concrete mixture into the form. Experimental load test of slab on subsoil was performed on fibre concrete slab with plan dimensions 2000 x 2000 mm and thickness 150 mm. Concrete slab was loaded in the middle with force load step 75 kN. AE measurements were provided using track sensors.

The Structural Characteristics of Lightweight Aggregate Concrete Beams

This paper aims to investigate the structural behavior of reinforced lightweight concrete beams. Attapulgite aggregate and crushed clay brick aggregate were used as coarse lightweight aggregate to produce structural lightweight aggregate concrete with 25 Mpa and 43.6 Mpa cube compressive strength and 1805 Kg/m3 and 1977 Kg/m3 oven dry density respectively. The result of reinforced lightweight concrete beams compared with reinforced normal weight concrete beams, which have 50.5 Mpa cylinder compressive strength and 2317 Kg/m3 oven dry density. For each type of concrete two reinforced concrete beams with (1200 mm length × 180 mm height × 140 mm width), one of them tested under symmetrical two-points load STPL (a/d = 2.2) and another one tested under one-point load OPL (a/d=3.3) at 28 days. The experimental program shows that a structural lightweight aggregate concrete can be produced by using Attapulgite aggregate with 25 MPa cube compressive strength and 1805 Kg/m3 oven dry density and by using crushed clay brick aggregate with 43.6 MPa cube compressive strength and 1977 Kg/m3 oven dry density. The weight of Attapulgite aggregate concrete and crushed clay bricks aggregate concrete beam specimens were lower than normal weight aggregate concrete beams by about 20.56% and 13.65% respectively at 28 days. As for the ultimate load capacities of beam specimens, the ultimate load of Attapulgite aggregate concrete beams tested under STPL were lower than that of crushed clay bricks aggregate concrete beams and normal weight aggregate concrete beams by about 4.85% and 5% respectively. While the ultimate load capacities of reinforced Attapulgite concrete beams tested under OPL were lower than that of reinforced crushed clay bricks aggregate concrete beams and reinforced normal weight aggregate concrete beams by about 10.3% and 10.5% respectively. Finally, Attapulgite aggregate concrete and crushed clay bricks aggregate concrete showed ductility and toughness less than that of Normal weight aggregate concrete.

Effect of Mould Size on Compressive Strength of Green Concrete Cubes

This paper is aimed to evaluate the effect of mould size on compressive strength of concrete cubes made with recyclable concrete aggregates. Natural coarse aggregates were replaced with 50% recycled aggregates from old demolished concrete. Five different mould sizes were used to cast 420 concrete cubes using 1:2:4 mix and 0.55 water/cement ratio. In each size equal number of cubes was cured for 3, 7, 14 and 28-day. After curing, weight of cubes was determined followed by testing for compressive strength in universal load testing machine with gradually increasing load. From the obtained results the strength correction coefficients were computed keeping 28-day cured standard size cubes as control specimens. Also, numerical expression based on regression analysis was developed to predict the compressive strength using weight of cube, area of mould and curing age as input parameter. The numerical equation predicts the compressive strength very well with maximum of 10.86% error with respect to experimental results.