Strength Of Concrete Cubes Research Articles

Causes of failure in concrete elements buried in lagoon water

The effect of salt attack on reinforced concrete structures in marine environment has become a source of concern to stakeholders in the construction industry. This trend has led to cracks and sometimes failure of structural members that are exposed to this environment. This study investigated the strength performance of concrete elements in lagoon water which is an offshoot of the Atlantic Ocean in Lagos State, Nigeria. A total of ten 150 mm cubes, and ten 150 mm × 150 mm × 600 mm reinforced concrete beams were cast using Portland limestone cement of 42.5-R at 28 days strength of 40 N/mm2 and cured in both fresh and Lagoon water with water-cement ratio of 0.45. Chemical analysis were carried out to determine the concentration of ions. Mechanical tests were also carried out on the concrete elements. The chemical analysis result showed that Calcium (Ca) was the predominant element having 61.62% in the concrete sample cured with lagoon water while concrete sample cured in fresh water had 51.77%. The flexural behaviour of reinforced concrete beams showed that the flexural stiffness of beams were 15.1 N/mm2 and 12.46 N/mm2 in the lagoon and fresh water, respectively. The compressive strength of concrete cubes cured in fresh water was 42.67 N/mm2 while that of lagoon water was 34.22 N/mm2. The preliminary results showed that concrete gained strength at the early stage for reinforced concrete beams buried in the Lagoon and reduced in strength at the early stage for concrete cubes buried in Lagoon. The result of the compressive strength showed that the high presence of salt could have contributed to the cracks and eventual spalling of concrete elements in marine environment.

Comparative study of Ikirun and Osogbo Slag on concrete grade 20

This study examined the use of Prism Steel Slag (PSS) and Machine Iron Slag (MIS) as partial replacement of coarse aggregate in concrete. Coarse aggregates were partially replaced with PSS and MIS at 0%, 10%, 20%, 30%, 40% and 50% respectively. A total of 132 concrete cubes of sizes 150 mm x 150 mm x 150 mm were cast and cured in water for 7, 14, 21 and 28 days respectively. Mix ratio of 1:2:4 was adopted with w/c ratio of 0.45 and batching was done by weight. The slump result indicated that the fresh concrete becomes stiff as the percentages of PSS and MIS increases. However, the compressive strengths of concrete cubes increased as the curing ages increases. 50% PSS and 40% MIS can successfully be used as partial replacement of coarse aggregate in the production of concrete grade 20. Keywords: Concrete, Coarse Aggregate, Strength, Machine Iron Slag, Prism Steel Slag

The effect of acidic environment on the concrete utilizing palm oil fuel ash

High-performance concrete (HPC) is widely used in construction projects, however, it has a large carbon footprint during the manufacturing of cement. Malaysia is one of the largest palm oil producers, and in the extraction of palm oil, it produces a lot of waste by-product, one of which is palm oil fuel ash (POFA) that would put an impact on the environment. Recently, there are many research studies revealed that POFA has a pozzolanic characteristics which can partially replace the cement to produce an eco-friendly concrete. This study illustrates the compressive strength and durability of concrete utilizing micro POFA. POFA, which was obtained from a local source, was sent for treatment and grinding procedure to remove excess carbon content and obtain 45μm size. 0%, 10%, 20% and 30% of micro POFA were used to replace the Portland cement in the used mixes. After curing age of 28 days, compressive strength and acid resistance of concrete cubes were investigated. Two different acids, hydrochloric acid (HCL) and sulfuric acid (H2SO4) were used to provide different aggressive environments for the concrete cubes. Two different optimum replacement percentages of POFA regarding to the acid resistance were determined by using the compressive strength loss, total mass loss and the visual inspection before and after the submersion. As two different acids were used, the rates of two acid attack on the concrete were studied in terms of mass loss throughout the submersion period. The results showed that the replacement percentage of 20% had the highest compressive strength in 28 days compressive strength test. Besides that, in terms of durability, even though the HPC utilizing 20% of replacement percentage of POFA did not have the highest acid resistance to the acid attack, however it had the highest compressive strength after the submersion in two different acids. This research showed that the replacement of micro POFA in HPC, possessed a significant improvement in terms of compressive strength and acid resistance.

Assessment of Concrete Durability in Buildings: the Effects of the Quality of Cements Available in Lagos, Nigeria

This paper presents an investigative research that aims to find the effects of the cements available in Lagos, Nigeria on the durability of concrete within the study area. This is in an attempt to stem the rate of building failures in Lagos, Nigeria. The physical, the mechanical and the microstructural properties of the cements have been determined and compared with the standard properties as specified in relevant standards. 150mm cubes have been cast with these cements and all the sources of aggregates within the study area. Laboratory findings have discovered that all the cements investigated have fallen short of the expected strengths specified in standards but the labelled brands had values close to the strength standards but the unlabeled ones have fallen far short of the standard strength. The chemical analysis has complied with standard requirements except for their loss on ignition (LOI) values and the chemical properties have been complemented by the microstructural morphology as determined with the Scanning Electron Microscope (SEM) though the unlabeled brands have tendencies for alkali silica reactivity due to higher levels of alkali present in them. In assessing their performance in concrete, the concrete cube strength has met the expected 20MPa except for the unlabeled brands that have fallen a little short of it. The effects of these cements have been discovered to be very significant on the concrete durability within the study area. It is thereby recommended that the Nigerian regulatory agencies on cements make more efforts in order to ensure that cement manufacturers in Nigeria improve the quality of their cement brands in order to standard strength specification. All cements should be temporarily used as a 32.5 strength class, despising the labelled 42.5, pending when the manufacturers would fully comply their products to standard. Copyright © 2019 Praise Worthy Prize S.r.l. - All rights reserved.

Effect of Water Cement Ratios on Compressive Strength of Palm Kernel Shell Concrete

This study examined the effect of varying water cement ratio on the compressive strength of concrete produced using palm kernel shell (PKS) as coarse aggregate at different replacement levels. The replacement levels of coarse aggregate with palm kernel shells (PKS) were 0%, 25%, 50%, and 100% respectively. PKS concrete cubes (144 specimens) of sizes 150mm x 150mm x 150mm were cast and cured in water for 7, 14, 21 and 28 days respectively. A mix ratio of 1:2:4 was adopted with water-cement ratio of 0.45, 0.5, and 0.6 respectively while the batching was done by weight. Slump test was conducted on fresh concrete while compressive strength test was carried out on the hardened concrete cubes using a compression testing machine of 2000kN capacity. The result of tests on fresh concrete shows that the slump height of 0.45 water cement ratio (w/c) increases with an increase in PKS%. This trend was similar to 0.50 and 0.60 w/c. However, the compressive strength of concrete cube decreases with an increase in w/c (from 0.45 to 0.60) but increases with respect to curing age and also decreases with increase in PKS%. Concrete with 0.45 water-cement ratio possess the highest compressive strength. It was observed that PKS is not a good substitute for coarse aggregate in mix ratio 1:2:4 for concrete productions. Hence, the study suggest the use of chemical admixture such as superplasticizer or calcium chloride in order to improve the strength of palm kernel shells-concrete.

Comparative study on synthesis and properties of geopolymer fine aggregate from fly ashes

The growing demand for river sand has caused rapid depletion of this natural resource, and hence it is necessary to find an alternative to replace natural river sand. In this aspect, few recent studies have shown the potential of using geopolymerization reactions to produce fine aggregates using class F fly ash (FFA) to replace natural sand. In this study, an attempt has been made to utilise waste coal ash (class C and class F fly ash) to produce artificial fine aggregate by using geopolymerization reactions. The physical properties of both class C fly ash geopolymer fine aggregate (C-GFA) and class F fly ash geopolymer fine aggregate (F-GFA) were compared with the properties of natural sand and manufactured sand (M-sand). The mortar specimen using C-GFA and F-GFA gained a strength of 83% and 75% of 28-day compressive strength of natural sand mortar cubes and 89.01% and 81% of M-sand mortar cubes respectively. The concrete specimen using C-GFA and F-GFA gained 80.24% and 75% of 28 days compressive strength of natural sand concrete cubes and 83.9% and 77% of M-sand concrete cubes respectively. This study shows that both C-GFA and F-GFA can be used to synthesize alternative fine aggregates to natural sand and M-sand that are used in construction activities.

Study on Strength Properties of Concrete with Ceramic Waste Aggregate and Silica Fume Admixture

The ceramic waste is used as a coarse aggregate replacement in concrete is a two way beneficial process that involves minimization of resources for construction and processing of hazardous industrial wastes that cannot be recycled. The ceramic waste obtained from waste dismantled building were used as coarse aggregate 10%, 20%, 30%, 40% and 50% replacement. To improve the mechanical properties silica fume is added as admixture in the concrete. The optimum percentage replacement was obtained considering the strength as well as the objective of using ceramic waste aggregate. The compressive strength of concrete cubes were tested . The compressive strength of aggregate replaced concrete has been compared to that of conventional concrete and the results are evaluated.

Beneficiated pozzolans as cement replacement in bamboo-reinforced concrete: the intrinsic characteristics

The use of concrete containing supplementary cementitious materials has gained popularity as an eco-efficient and sustainable alternative to a number of concrete applications. In this study, beneficiated pozzolans, ground granulated blast furnace slag (GGBS) and metakaolin (MK), were used as partial replacement of ordinary Portland cement in bamboo-reinforced concrete. In the mixtures, river sand and granite were used as fine and coarse aggregates, respectively. The compressive strength of concrete cubes, split-tensile strength of concrete cylinders, and flexural strength of reinforced concrete beams were determined after stipulated curing regimes. The morphology and mineralogy of bamboo and selected concrete mixtures were obtained using scanning electron microscope and X-ray diffraction, respectively. The concrete samples having blended cement were found to have better compressive and split-tensile strength than those made with conventional binder. Also, the mechanical characteristics of the samples improved up to 40% GGBS substitution. However, steel-reinforced concrete developed better flexural strength than the bamboo-reinforced concrete (BRC). The study recommends pretreatment of bamboo to ensure its adequate bonding with the cement paste, so as to achieve optimum performance of BRC.

Experimental Study on Compressive Strength of Cement Concrete Cubes by Partial Replacement of Cement with Egg Shell Powder

Experimental Study on Compressive Strength of Cement Concrete Cubes by Partial Replacement of Cement with Egg Shell Powder

Flexural Behaviour of Fibre Reinforced Concrete Beams with Different Aspect Ratios

The performance of conventional concrete is enhanced by the addition of fibres in concrete. Consequently the brittleness in concrete is reduced, and its acceptable ductility is also ensured by this addition. In this paper the strength of concrete cubes, cylinders and beams cast using M25 grade concrete and reinforced with steel and polypropylene fibres is presented. Also hybrid fibres with crimped steel and polypropylene were used in a concrete matrix to study improvements in the strength properties of steel, polypropylene and hybrid polypropylene as well as steel (crimped) fibres of various proportion i.e., 0.25%, 0.5%, 0.75%, 1% and 0.5% (0.25% of steel and 0.25% of polypropylene), 0.75% (0.5% of steel and 0.25% of polypropylene, 0.25% of steel and 0.5% of polypropylene) and 1% of various combinations of hybrid fibres for 7,14 and 28 days. The main reason for synthetic fibres in the concrete matrix is to improve the post cracking response of the concrete to improve the energy absorption capacity and ductility as well as to provide crack resistance and control. The introduction of this type of concrete was brought in as a solution to develop concrete with enhanced flexural and tensile strength. In this paper we analysed and present a comparison between conventional concrete and fibre reinforced concrete, leading to a crack free structure.

Effect of elevated temperature on the compressive strength of concrete produced with pulverized steel mill scale

Concrete materials in structures are usually exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. The effect of partial replacement of cement with pulverized steel mill scale (PSMS) on the compressive strength of concrete cubes was investigated in the first test. Furthermore, the influence of elevated temperatures on the compressive strength of the concrete cubes with cement partially replaced with PSMS was examined. For the second test the cubes were exposed to elevated temperatures ranging from the ambient temperature to 750°C in steps of 250°C for 2 hours and allowed to cool for 24 hours. Based on results of tests, partial replacement of cement with 10 % PSMS is recommended for use in concrete production and resistance to elevated temperature. The studies show that at this replacement, the concrete compressive strength is not adversely affected when the elevated temperature reaches 500°C. http://dx.doi.org/10.4314/njt.v36i4.6

Effect of Ground Granulated Blast Furnace Slag as Partial Cement Replacement on Compressive Strength of Concrete

Abstract The main objective of this research work is to determine the optimum replacement percentage of GGBS which can be suitably used. To fulfill the objective, various properties of concrete using GGBS have been evaluated. Mix design has been arrived for M25 concrete. Fineness, specific gravity (cement and GGBS), normal consistency, initial and final setting time and compressive strength of cement have been found out. Particle size distribution, bulking of fine aggregate, specific gravity, water absorption of fine aggregate and coarse aggregate are also found out. Three sets of experiments have been conducted for the compressive strength of concrete cubes without GGBS in which total nine concrete cubes have been casted and are tested at 7, 14 and 28 days. Then afterwards, 63 cubes, out of which, nine cubes each of 10, 20, 30, 40, 50, 60 and 70%, GGBS replacement are also casted and are tested at 7, 14, and 28 days. Slump cone test has also been performed to find out the workability of control concrete and concrete with different percentage replacement. From the experimental investigations, it has been observed that, the workability of concrete increases with increase in percentage of GGBS. Compressive strength of concrete increases as the percentage of GGBS increases up to 40% replacement, beyond which it starts decreasing. The investigation revealed that the use of ground granulated blast-furnace slag, which is hazardous to the environment, may be used as a partial replacement of cement, which leads to economy and in addition, by utilizing the industrial wastes in the useful manner, the environment pollution is also reduced to great extent, which leads to sustainable development. Keywords : Ground granulated blast furnace slag, compressive strength, workability, particle size distribution, specific gravity Cite this Article Pandey Rajesh Kr, Abhishek Kumar, Ashish Mishra. Effect of Ground Granulated Blast Furnace Slag as Partial Cement Replacement on Compressive Strength of Concrete. Journal of Construction Engineering, Technology and Management. 2017; 7(3): 1–10p.

Flexural behavior of concrete-filled aluminum alloy circular hollow section tubes

This paper presents an experimental investigation on flexural behavior of concrete-filled aluminum alloy circular hollow section (CHS) tubes under pure in-plane bending. A total of 28 circular concrete-filled aluminum alloy tubes (CFAT) with nominal concrete cube strengths of 30 MPa and 50 MPa were tested. The flexural strengths, failure modes, flexural stiffness, ductility, bending moment versus mid-span deflection curves, overall vertical deflection curves, bending moment versus longitudinal strain curves and longitudinal strain distribution curves of circular CFAT beams are reported. It is demonstrated that the comparatively large wall thickness of aluminum alloy CHS tube enhanced the bearing capacity, the bending deformation capacity and the ductility of circular CFAT beams. Whereas, the concrete strength generally has insignificant influence on the flexural strength, flexural stiffness and ductility of circular CFAT beams. The current design specifications for the CFST are generally inappropriate for circular CFAT beams under pure in-plane bending with high scatter of predictions. Further research is still required to propose accurate design rules for circular CFAT beams.

Dune sand concrete-filled steel tubular (CFST) stub columns under axial compression: Experiments

The behaviour of dune sand concrete-filled steel tubular (CFST) stub columns under axial compression was experimentally investigated in this paper, where the nominal cube strength of concrete was 60MPa. A total of 24 specimens including 20 dune sand CFST stub columns and 4 reference hollow steel tubular stub columns were tested. The effects of tube thickness, cross-sectional dimension and concrete infill on the behaviour of the composite stub columns were investigated. The results showed that, similar to conventional CFST stub columns, the tested dune sand CFST stub columns behaved in a ductile manner and displayed an outward buckling failure model with high compressive strength. It indicates that it is feasible to use dune sand to replace normal sand to fabricate CFST columns in regions close to deserts. Comparisons were made between the test results and the predicted ultimate strength using the existing codes AIJ (2008), AISC360-10 (2010), BS5400 (2005), DBJ/T13-51-2010 (2010) and EC4 (2004). Generally, these codes are conservative but acceptable for predicting the ultimate strength of dune sand CFST stub columns.

Characteristics of Cement Concrete with Nano Alumina Particles

Concrete can be nano-engineered by incorporating nano sized building blocks or objects (e.g., nano particles and nano tubes) to control material behaviour and add novel properties. In this work an attempt has been made to study the effect of nano alumina on the properties of concrete composite. In order to investigate the effect of nano-alumina on the mechanical strength of cement composite, the specimens with different volume percentages (0%, 0.5%, 0.75% and 1%) nano-alumina, in each proportion three sample were cast totally making 58 specimens and after 28 days of curing they were tested. Based on experiment, the compressive strength of concrete cubes was all increased by incorporating nano alumina into matrix, when the fraction of nano alumina was 1% of the cement by weight the compressive strength of composites increased by 33.14% at 28 days. The test results showed that addition of nano alumina enhanced the compressive strength and reduced the initial setting time of concrete composite. Micro analysis was carried out by Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS).The studies indicated that nano particle was uniformly distributed by improving the microstructure of concrete.

Effect of Re-vibration Process on Axial Capacity of Short Reinforced Concrete Circular Columns

A considerable amount of research work has been performed on the effects of vibrating of fresh concrete on the reduction of shrinkage and creep, the improvement bond stress between reinforcing bar and concrete, reduction the concrete permeability and improvement of the mechanical properties of concrete (tension and compression). Series of tests on reinforced concrete circular column, cubes and cylinders were carried out to study the effect of re-vibration duration on axial strength of column, compression strength of concrete cubes, and tensile strength of cylinders. Different compressive strengths of concrete and different size of aggregate were considered in this investigation. The test results show that, the re-vibration operation improves the tensile and compressive strength of concrete. The stiffness of columns increased with increasing the re-vibration duration up to1.5 times the initial vibration duration. Size of aggregate has significant effect on the improvement properties of concrete due to re-vibration. Increase the time duration of re-vibration delay the appearance of first crack.

Measurement and Improvement the Quality of the Compressive Strength of Product Concrete

The research dealt with studying path technology to manufacture of concrete cubesaccording to specification design of Iraq to the degree of concrete C20 No. 52 of 1984, and inwhich sample was cubic shape and the dimensions (150 × 150 × 150) mm for each dimensionsand the proportion of mixing of the concrete is (1:2:4) using in the casting floor. For concreteresistance required that achieve the degree of confidence of 100%, were examinedcompressive strength 40 samples of concrete cubes of age 28 days in the Labs section of CivilDepartment – Technical Institute of Babylon, all made from the same mixing concrete. Where,these samples classified within the acceptable tests were adopted in the implementation ofinvestment projects in the construction sector. The research aims first, to measure thecompressive strength of concrete cubes because the decrease or increase the compressivestrength from specification design contributes to the failure of investment projects in theconstruction sector therefore, test was classified units that produced within damaged units.Second, to study an improvement the quality of compressive strength of concrete cubes.Results show that the proportion of damaged cubes are 0.00685, compressive strength wasachieve confidence level 99.5% and producing of concrete cubes within the acceptable level ofquality (3 Sigma). The quality of compressive strength was improved to good level useadvanced sigma levels.

Measurement and Improvement the Quality of the Compressive Strength of Product Concrete

The research dealt with studying path technology to manufacture of concrete cubes according to specification design of Iraq to the degree of concrete C20 No. 52 of 1984, and in which sample was cubic shape and the dimensions (150 × 150 × 150) mm for each dimensions and the proportion of mixing of the concrete is (1:2:4) using in the casting floor. For concrete resistance required that achieve the degree of confidence of 100%, were examined compressive strength 40 samples of concrete cubes of age 28 days in the Labs section of Civil Department – Technical Institute of Babylon, all made from the same mixing concrete. Where, these samples classified within the acceptable tests were adopted in the implementation of investment projects in the construction sector. The research aims first, to measure the compressive strength of concrete cubes because the decrease or increase the compressive strength from specification design contributes to the failure of investment projects in the construction sector therefore, test was classified units that produced within damaged units. Second, to study an improvement the quality of compressive strength of concrete cubes. Results show that the proportion of damaged cubes are 0.00685, compressive strength was achieve confidence level 99.5% and producing of concrete cubes within the acceptable level of quality (3 Sigma). The quality of compressive strength was improved to good level use advanced sigma levels . DOI: http://dx.doi.org/10.25130/tjes.24.2017.20

Effect of Partial Replacement of Slag and Nano Silica Infused Slag on Properties of Concrete

Investigations were carried out on the changes in properties of concrete when steel slag is used in concrete in its normal form and after modifying its properties by infusing it with nano-silica. The sand is replaced by steel slag and modified steel slag by 10%, 20% and 30% in M30 grade concrete. Tests results on compressive strength and workability of concrete revealed that compressive strength of concrete cubes after 28 days increased by 25.4%, 26.4% and 45.2% for 10%, 20% and 30% respectively after replacing sand by steel slag. After modification of steel slag properties by infusing it with nano silica, the 28 days compressive strength was observed to be increased by 38.19%, 35.80% and 27.89% for 10%, 20% and 30% as compared to traditional concrete mix respectively after replacement. Infusing steel slag with nano silica increased the compressive strength of concrete mix by 20.17%, 25.74% and 49.64% for 10%, 20% and 30% respectively when compared to normal steel slag concrete mix. It was also observed that using steel slag in concrete mix also influences on water consumption in concrete mix. Workability tests conducted using 0.45 and 0.5 w/c ratio and the inference was that the workability increased with the increase in percentage of steel slag but workability decreases with the increase in percentage of modified steel slag.

Experimental Time-Dependent Deflection of High Strength Concrete Panels

This work presents an experimental study on both short-term and long-term deflections for a period more than seven months of reinforced high and normal strength reinforced concrete two-way flat plate panels. Four reinforced concrete panels with dimensions of (960×960×50) mm were investigated with simply supported edges. Concrete cube strength is about 75 MPa for HSC panels, and 30 MPa for the control panel. Sustain load kept along the entire test period and at the end, the loads is removed and the recoverable deflection was measured. It’s been concluded that the rate of increase in HSC panels’ long time deflection is less than that of NSC panels, also the long-term deflection is highly reduced by increasing the compressive strength of concrete and the long term deflection reduced about 20% when compressive strength increased from 25 to 65 MPa.