Effect of Fibre Hybridization on Compressive Strength, Split Tensile Strength and Water Permeability of SFRC

The paper presents results of an investigation conducted to study the compressive strength, split tensile strength and water permeability of fibre concrete mixes containing steel fibres in mono, binary and ternary combinations. Steel fibres of different lengths i.e. 12.5 mm, 25 mm and 50 mm having constant diameter of 0.6 mm were used to obtain mono, binary and ternary combinations. A reference concrete mix with no fibres was also used for comparison purpose. The total fibre volume fraction was kept at 1.0% in all the mixes. Compressive strength, split tensile strength and water permeability tests were conducted of specimens of size 100 x 100 x 100 mm after 28 days of curing.  It has been observed that a fibre combination of 33% 12.5 mm + 33% 25 mm + 33% 50 mm long fibres can be adjudged as the most appropriate combination to be employed  in HySFRC for compressive strength, split tensile strength and water permeability

Pengaruh Komponen Kimia Dan Ikatan Pembuluh Terhadap Kekuatan Tarik Bambu

. Bamboo is natural composite material which is built from many types of cells. Fibers cells which are bundled become vascular bundles have highest contribution toward the strength of bamboo split among others. Besides the amount of vascular bundles, the bamboo split strength is also determined by chemical component of cell walls and its position (internodes/node). This research reported that the tensile strength has positive correlation with the amount of vascular bundles. If the amount vascular bundles increase, then the tensile strength also increases. The increasing of lignin contents in cell wall proportionally and quadratically increases the tensile stress of internodes and node of bamboo split, respectively. This research did not found the maximum stationer point of quadratic equation for lignin content effect toward bamboo split tensile strength, thus the tensile strength always increase along with the lignin content in this research range (<33%). Correlation value between tensile strength and ratio of alpha cellulose to holocellulose is high which prove that alpha cellulose highly contribute to the tensile strength even though best subset regression procedure could not identified this phenomenon because of its autocorrelation occurrence

Temporal characterization of rock dynamic destruction

Dynamic strength tests published in literature have been analysed by structuraltemporal damage criteria. Parameter τ - incubation time - describing material stability behaviour under high-rate influences have been estimated for Kimachi sandstone, Inada granite and Tage tuff. Two types of dynamic tensile experiments have been used: split Hopkinson pressure bar and spalling. Purely dynamic effect of fracture delay have been observed in the case of Kimachi sandstone and discussed

Ae-sigma Analysis in Split-tensile Test of Fiber-reinforced Concrete (Frc) at Meso-scale

Crack control plays a crusial role in the performance life of concrete structures. It present a serious treat to the performance of concrete structures. Micro-cracking will appear when the strength of concrete is approached. Each of micro-crack occured inside concrete will produce a transient elastic wave which could be used to detect and localize cracks as well as to analize kinematically the fracture mechanisms in concrete. In this scientific paper, the SiGMA analysis is applied to the split-tensile tests of FRC to study the relation between the generation of macro-scale tensile crack and accumulation of meso-scale cracks as well as to know the role of the applied fiber on the cracking process of concrete. Results showed that the relation between macro-scale tensile failure and nucleation of AE sources in meso-scale is clarified in Split-tensile test. At the macro-scale, tensile-type cracks are only observed, while all kinds of tensile, mixed-mode and shear cracks are identified at the meso-scale. During propagation of tensile cracks at the macro-scale, other types of AE sources of mixed-mode and shear cracks were actively identified. Thus, nucleation of the fracture process zone is confirmed around the final failure surface.Mechanisms of macro-scale tensile failure process in concrete are clarified as the crack accumulation process at meso-scale determined by the SiGMA analysis. There exists a clear relation between macro-scale tensile failure process and nucleation of AE- sources in the meso-scale in the split-tensile test for the tensile strength of concrete

Physical properties of concrete containing graphene oxide nanosheets

Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water−cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete

Studi Eksperimen Kuat Tekan Beton Berdasarkan Urutan Pencampuran Material Penyusun Beton dengan Adukan Manual

The aim of this research where to determine the effect of mixing the precursor material is done manually to slump, the characteristic concrete compressive strength, tensile strength and modulus of elasticity of concrete sides. Testing includes compressive strength, tensile strength and modulus of elasticity sides. Determination of concrete mix using methods ACI modification. The planned concrete quality is fc '= 22.5 MPa. The experimental results obtained sequence of mixing cement, sand, water, crushed stone which produces most compressive strength characteristics compared with other mixing sequences with an average of 29.124 MPa. For a split tensile strength values ​​obtained sequence of mixing sand, cement, crushed stone, water and the order of mixing cement, sand, water, crushed stone produce the most divisive tensile strength compared with other mixing sequences with an average of 2.978 MPa. As for the value obtained sequence modulu elasticity mixing cement, sand, crushed stone, water produces elastic modulus of the most good with an average of 34336,023 MPa

Evaluation of Deicer Impacts on Pervious Concrete Specimens (Phase II)

This research examined the chemical degradation of pervious concrete due to calcium chloride or magnesium chloride deicers. The project consisted of Phase I, Phase IIa, and Phase IIb. Phase I was previous work where a testing protocol was developed to mimic deicer applications. Phases IIa and IIb are parts of this project. Phase IIa used split tensile testing on Phase I specimens and further evaluated the chemical data from Phase I magnesium chloride applications. Phase IIb repeated the Phase I protocol for a larger number of new ordinary Portland cement specimens and evaluated the impact on strength using the unconfined compressive strength test. The hypotheses were based on complexation and precipitation chemistry. Specimens subjected to calcium chloride showed visible degradation. Specimens exposed to magnesium chloride deicer showed a large increase in loss of calcium ions in Phase I. Both deicers showed a loss in strength compared with a water control in Phase IIb. Results from the split tensile testing were inconclusive. The protocol from Phase I with the unconfined compression test may be an effective testing procedure to determine if different designs might be more resistant to chemical degradation by these two deicing chemicals

Kajian Karakteristik Mekanik Roller Compacted Concrete (Rcc) Sebagai Bahan Perkerasan Jalan

RCC concrete pavement is concrete pavement that has durability, economic value, long life and low maintenance service life. In this study conducted in the field compaction with baby roller more or less as much as 3-5 times the trajectory, and retrieval of test specimen cubes (10x10x10) and beam (10x10x30), with a concrete cutting tools. Taking a test specimen in the laboratory of conventional concrete cubes (15x15x15). The composition of mixtures used were water: sand: split: cement is 108:811:1217:300 (kg/m3). Variations in the age of treatment (7,14,21 and 28 days), and performed two tests, namely: the testing of compressive strength and lentur.Hasil tensile strength showed that the mixture of the same compressive strength and flexural strength RCC is higher than conventional concrete., more economical, faster utilization after the implementation of the work. Compressive strength obtained at 28 days was 29.25 MPa and 5.14 MPa flexural tensile strength, is still included in the range required by the ACI (American Concrete Institute) that the range of tensile strength for RCC split between 400 (2.75 MPa) and 600 psi (4.13 MPa) at 28 days, for compressive strength are eligible for RCC mixtures where, according to the specifications for RCC of the PCA (Portland Cement Association) where the requirements are between 28 MPa - 69 MPa

Potentials of Momordica angustisepala fiber in enhancing strengths of normal portland cement concrete

Presence of cracks in concrete affect the integrity. It reduces the life expectancy of concrete structures and is often responsible for collapse of structures, especially in the developing nations. At the root of these cracks is the very low tensile strength of concrete. Various techniques have been suggested for the enhancing the tensile strength, among which is the use of discontinuous micro fibers of various nature. This research investigated the use of Momordica angustisepala (Ma) fiber to enhance concrete strength. Concrete containing coconut fiber was adopted as a control. Slump test, air entrainment test, compression test and split tensile test were carried out on specimens. Results of the research indicate that an optimum Momordica angustisepala fiber contents of 0.25 and 0.5% enhanced respectively the compressive strength by 4.37% and the tensile strength by 10%. The results clearly show that this renewable material has the potential to enhance the compressive and tensile strengths of concrete