Cementitious Material In Concrete Research Articles

MICROSTRUCTURAL CHARACTERIZATION OF RICE HUSK AND RESIDUAL ASH FOR THE PRODUCTION OF SUPERIOR BLENDED CONCRETE

Several industrial by-products such as fly ash, silica fume and slag are widely used as supplementary cementitious materials in concrete. In addition to attain designed characteristic strength of structural concrete, it is very imperative to maintain the strength throughout service life of the structure. Supplementary cementitious materials are commonly used in the modern cement manufacturing process to achieve durable and sustainable concrete. Earlier research studies have clearly reported that higher strength and significant reduction in permeability of concrete containing agricultural waste products such as sugarcane bagasse ash and rice husk ash compared to control concrete. However, utilization of rice husk ash and sugarcane bagasse ash in blended cement production is limited to a greater extend as a consequence of lack of understanding and characterization of these materials. Microstructure of rice husk and silica distribution in the residual ash due to controlled burning is not available in the existing literature. This paper reviews reactive silica formation in the rice husk and its residual ashes based on the microstructure and its influence on the pozzolanic performance. Moreover, rice husk ash was processed based on suitable methodology and compressive strength of mortar was found to be high compared to control specimens.

Assesment of Pozzolanic Performance of Sugarcane Bagasse Ash

AbstractSugarcane bagasse ash is obtained as a by-product from cogeneration combustion boilers in sugar industries, and is reported to be a useful supplementary cementitious material in concrete. A clear evaluation of pozzolanic activity of sugarcane bagasse ash is imperative to achieve its effective utilization in concrete instead of being disposed as a waste in enormous quantities. Pozzolanic activity of raw sugarcane bagasse ash and a processed sample of the same was assessed by five different standard methods in this study. The methods used were: strength activity index test, lime reactivity test, Frattini test, electrical conductivity test, and lime saturation test. In addition, chemical and mineralogical analyses were also performed on the bagasse ash. Durability performance of concrete with bagasse ash blended cement was evaluated and compared with fly ash-based concrete. The results from the studies indicate that raw bagasse ash has low pozzolanic activity due to presence of fibrous carbon particl...

An Image Processing Approach to Coarse Aggregate Feature Extraction in Hardened Concrete

From 1 inch down aggregate, 10 cylindrical samples were prepared in the laboratory according to ASTM gradation. This paper presents an automated digital image processing technique for capturing the microstructure of cement concrete. Cement concrete compound material of these three phases Aggregate, sand mastic and air void. Aggregate shape, gradation and orientation also play an important role. In this paper tried to detect and separate these three phases and measure the value of them by image processing technique. Methodology consists of Concrete Mix Design, Sample Preparation, Compressive Strength Test, Sample Cutting, Image Analysis, Extracting the Data Required, Data Analysis, Comparing the Results with ASTM Gradation Curve. Concrete mix design is the process of choosing suitable ingredient of concrete and determines their relative quantities with the object of producing as economically as possible concrete of certain minimum properties, notable workability, strength and durability. DC is a destructive technique, due to the need for cut sample surfaces and fails to capture the air void distribution but it has the advantage of capturing greater aggregate detail on an individual plane and being relatively inexpensive. As we are doing our project with destructive technique, therefore we cut the samples at different level. After the samples are prepared, each specimen was transversely sawed at the ½ inch from bottom and top through core cutter to get the cross section of the sample. Core cutter is operated through electric power. In this way, we get cross section for each specimen at different level i-e top, ¼ (a) from top, 2/4 from top (b), ¾ from top(c),4/4 from the top (d) & at bottom. After cutting of all the samples at different level of sample, Images are then acquired with digital camera (Xperia 8 megapixel) so that the different constituents of concrete should be clearly visible. Image analysis will be performed on these images with “Image J” the image analysis software. Analysis will be done in unit of inches. Image processing is a method to convert an image into digital form and perform some operation on it, in order to get an enhanced image or to extract some useful information from it. It is a process of meaningful information from images such as finding shapes, counting objects, identifying colors or measuring object properties. Extracting the data from images, the aggregate are labeled, and the data is exported to spreadsheet. After that finding the area and perimeter from the analysis data and make the graphs for the cross check of ASTM gradation curves. The digitally filtered images were utilized to calculate a gradation for the aggregate and compare with the real gradation of aggregate. The gradation of aggregate was determined by percentage retained in different sieve sizes according to volume.

Performance evaluation of sugarcane bagasse ash blended cement in concrete

By-products from a number of industrial processes are used as alternative supplementary cementitious materials in concrete. Sugarcane bagasse ash is mainly composed of amorphous silica and can be used as a pozzolanic material in concrete. Production of sugarcane bagasse ash (SCBA) based blended cements with different replacement levels of SCBA, and the performance of concrete with these cements in terms of compressive strength, heat of hydration, drying shrinkage and durability are discussed in this paper. Durability performance was investigated by five different methods in this study, namely oxygen permeability test, rapid chloride penetration test, chloride conductivity test, water sorptivity test, DIN water permeability test and Torrent air permeability test. The results from this study show that use of sugarcane bagasse ash in concrete prominently enhances its performance. Low heat of hydration, additional strength gain due to pozzolanic reaction, significant reduction in permeability because of pore refinement and similar drying shrinkage behavior were observed for bagasse ash blended concrete compared to control concrete.

ANALISA SIFAT KETEGUHAN PATAH DAN TEKAN BETON SEMEN DARI TULANG ROTAN

Indonesia has the potential of rattan is enough large, but the value of the sale and utilization is still limited as materials for baskets, furniture, handicrafts and so on. This research purpose to obtain bending and compressure strength properties when the rattan used for substitution of iron materaial making to cement concrete building simple houses. The raw material of used for research this is rattan has done processing (preservation and drying). Cement concrete frame made of rattan and molds for casting. Concrete frame rattan incorporated in the mold and filled dough (cement: gravel: sand = 1: 2: 3 plus water as needed). Treatment was observed that the diameter rattan (A) which includes: 8 mm (a1), 10 mm (a2) and 12 mm (a3); and the distance between the iron ring (B) which includes 11 cm (b1); 15 cm (b2); and 19 cm (b3). The number of repeat 3 times. Parameters observed bending and compressure strength.The results of the research rattan diameter 8-12 mm and the distance ring iron 11-19 cm produces bending strength from 18.24 to 40.13 kg /cm2 lower than cement concrete from iron materials (95.76 to 120.36 kg / cm2); and compressure strength from 28.33 to 42.85 kg/cm2 larger than from iron cement concrete materials (20 to 34.67kg/cm2). The results of the research show bending strength from rattan lower and compressure sterngth than big concrete from iron.Keywords: rattan, cement concrete, bending strength, compressure strength

Influence of Metashale as Cement Replacement on the Hygric Transport Properties of Concrete

This article is focused on the utilization of metashale as a supplementary cementitious material in concrete. Metashale as well as metakaolin is a product originating in the burning of clay materials, but in metashale production, the raw material is shale (aluminosilicates with granularity up to 0.02 mm). Four mixtures with cement replacement ranging from 0% up to 60% are designed and their properties are examined. Basic physical properties, mechanical strength, as well as hygric transport properties are measured and evaluated, in order to determine the influence of metashale on concrete properties. Experimental results show that for low amounts of cement replacement, metashale admixture leads to the improvement of studied material characteristics. When the material contains 40% of metashale, studied characteristics have almost similar values as the reference material. The worst values of measured properties are obtained for the replacement level of 60%. Nevertheless, all studied materials have appropriate properties to be applicable as high performance concrete.

Development of sugarcane bagasse ash based Portland pozzolana cement and evaluation of compatibility with superplasticizers

Sugarcane bagasse ash is a by-product from sugar industries and can be used as supplementary cementitious material in concrete. The development of new cementitious blends with processed sample of sugarcane bagasse ash is described in this paper. Utilization of various supplementary cementitious materials significantly influences fresh and hardened properties of concrete. Interaction of pozzolanic material with cement and chemical admixtures produces diverse effects in the fresh properties of blended cement concrete. This paper aims to ascertain the effect of different bagasse ash replacements of cement on the compatibility with superplasticizers in cement paste. Sugarcane bagasse ash based Portland pozzolana cements were produced with three different levels of replacement – 10%, 15%, and 20%. Marsh cone and mini-slump test were used to determine the effect of superplasticizer type and water binder ratio on the saturation dosage. From this study, it was observed that polycarboxylic ether based superplasticizer was more compatible with bagasse ash blended cement than sulphonated naphthalene based superplasticizer.

Elastic properties of RCC under flexural loading-experimental and analytical approach

In structural analysis, especially in indeterminate structures, it becomes essential to know material and geometrical properties of members. The codal provisions recommend elastic properties of concrete and steel and these are fairly accurate enough. The stress–strain curve for concrete cylinder or a cube specimen is plotted. The slope of this curve is modulus of elasticity of plain concrete. Another method of determining modulus of elasticity of concrete is by flexural test of a beam specimen. The modulus of elasticity most commonly used for concrete is secant modulus. The modulus of elasticity of steel is obtained by performing a tension test of steel bar. While performing analysis by any software for high rise building, cross area of plain concrete is taken into consideration whereas effects of reinforcement bars and concrete confined by stirrups are neglected. The aim of study is to determine elastic properties of reinforced cement concrete material. Two important stiffness properties such as AE and EI play important role in analysis of high rise RCC building idealized as plane frame. The experimental programme consists of testing of beams (model size 150 × 150 × 700 mm) with percentage of reinforcement varying from 0.54 to 1.63%. The experimental results are verified by using 3D finite element techniques. This study refers to the effect of variation of percentage of main longitudinal reinforcement and concrete grade. Effect of confinement is not considered and it appears in a separate study.

Test and Study on the Long-Age Performance of Cement Concrete Pavement Material

Experimental research is conducted to determine the long-age statistical parameters of road pavement properties such as flexural strength, flexural elastic modulus, compressive strength, and splitting strength after 18 months. Changes in regularity are analyzed, and the functional equations of the performance indices with the age of pavement concrete material are fitted. The differences in performance under the conditions of standard indoor curing and outdoor natural curing are then compared. The regularity of concrete strength varying with age, the relationship between flexural strength and splitting strength, and relationship between compressive strength and flexural strength are discussed. A comprehensive summary of the development rule of the long-age performance of road pavement concrete materials is performed. Finally, by analyzing the data of the ratio of compressive strength to flexural strength, it is recommended that controlling the flexural strength and water-cement ratio can reduce the brittleness of the concrete slab.

Sol Gel Characterization of Nano Kaolin

Nano kaolin is product from kaolin also known as white clay. Kaolin was established as supplementary cementitious materials in concrete. The inclusion of kaolin in concrete enhances strength and durability properties and prolongs concrete life span. In this research, nanokaolin will be develop by using sol gel technique by that involves high energy milling. The process of milling been influenced by time of milling, ball and jar type. Ceramic type Zirconia (Zi) is been used as jar and ball type in this process. Time of milling was set from four (4) hours and one (1) days. Sample will be analyse by using particle size analyser to see the particle size and surface area of kaolin. From the result shows the optimum milling period for nanokaolin is one day base on particle size compare to 4 hours. Furthermore, one day milling produces a massive increment of surface area compare to others. In conclusion, one day can be considered as the optimum cycle time in the production of nano kaolin.

Study on Vibrational Liquefaction Behavior of Air-Entrained Concrete

With respect to the liquefaction behavior of cement concrete material in a vibrational condition, the varying patterns of the vibrational viscosity coefficients, vibrational energy transfer and rheological mechanical behavior of air-entrained concrete and non-air-entrained concrete in a vibrational shear condition were compared by analyzing the vibrational liquefaction processes of concrete. The study has found that the vibrational viscosity coefficient of concrete with air entraining agent added increased notably so that air-entrained concrete can maintain good shuttering behavior during slip-form construction; presence of a large number of tiny bubbles in air-entrained concrete allowed more even transfer of vibrational energy in concrete; and the rheological mechanical behavior of concrete was improved after air entraining agents were added so that it became easier to liquefy by vibration and had better shaping effect upon completion of vibration. Keywords: air-entrained concrete, slip-form construction, cement concrete pavement, vibrational liquefaction

Calculated and Experimental Research on Shear Stability of Composite Pavement with Thin Asphalt Concrete Upper Layer

Based on the calculate analysis of shear-resistance stability of various asphalt mixtures for composite pavement with thin asphalt-cement concrete purpose during slow braking and emergency braking and anti-shear sliding stability test between asphalt and cement concrete, the shear resistance, characteristics and damage types of different types of asphalt mixtures in such pavement structure as well as the bond properties between different cement concrete surface cleanliness, strength, roughness and different asphalt binder materials were studied in this paper. The research result not only reveals that AR-AC13 and SMA-13, the broken gradation of modified asphalt with big viscosity and coarse aggregate, are the ideal asphalt mixture of such structure, but also indicates that the cement concrete surface should be clean and dry with good cleanliness as well as certain roughness and strength, and the concrete surface should be roughening treated through transverse groove or milling planer. Furthermore, rubber asphalt is proved to be the interlayer bonding material with ideal performance and price.

Analysis of Support Apparatus for Flexural Load-Deflection Testing: Minimizing Bias Caused by Arching Forces

Abstract It is in the best interests of standards development that bias and inter-laboratory variability be minimized in the reporting of test results. However, the apparatus sections of flexural test standards, such as ASTM C78, C1399, C1550, and C1609, may not adequately address important issues raised in this study that could adversely affect test results. Specifically, current standards specifications fail to address arching forces and effective span control. The mechanics of commonly applied journal-bearing-type support designs are analyzed and compared to an alternative ball or needle-bearing-type support design. The analysis demonstrates that significant bias can be introduced as a direct consequence of the mechanics that is the nature of journal-bearing-type supports. The analysis applies equally well to flexural tests involving small deformations of portland cement concrete or similar brittle materials, as it does to tests that are carried out involving relatively large deformations, such as with fiber-reinforced concrete.

Use of calcium carbide residue and bagasse ash mixtures as a new cementitious material in concrete

Calcium carbide residue (CCR) is a by-product of the acetylene gas production and bagasse ash (BA) is a by-product obtained from the burning of bagasse for electricity generation in the sugar industry. The mixture between CCR contains a high proportion of calcium hydroxide, while BA is a pozzolanic material, can produce a pozzolanic reaction, resulting in the products similar to those obtained from the cement hydration process. Thus, it is possible to use a mixture of CCR and BA as a cementitious material to substitute for Portland cement in concrete. The results indicated that concrete made with CCR and BA mixtures and containing 90kg/m3 of Portland cement gave the compressive strength of 32.7MPa at 28days. These results suggested that the use of ground CCR and ground BA mixtures as a binder could reduce Portland cement consumption by up to 70% compared to conventional concrete that requires 300kg/m3 of Portland cement to achieve the same compressive strength. In addition, the mechanical properties of the alternative concrete including compressive strength, splitting tensile strength, and elastic modulus were similar to that of conventional concrete.

Technical and economic aspects of using GGBFS for crack control mitigation in long span reinforced concrete structures

In 2009, China accounted for half of the global steel production. As a waste material or by-product in the manufacture process, over 160 million tonnes of blast furnace slag is generated annually, of which only 55% is recycled. Blast furnace slag, ground to an appropriate fineness, can be used as a cementitious material in concrete. However, most ground granulated blast furnace slag (GGBFS) in China ends up in low-grade applications, including ‘low heat’ cementitious material used in low-grade bulk concrete and cementitious material in mortar.A recently started project at XJTLU aims to contribute to the application of GGBFS in long-span concrete structures in China by avoiding/reducing the use of more expensive crack control reinforcement. The use of GGBFS in long-span concrete structures in China is currently held back by the following:(1)Lack of awareness of the potential commercial benefits;(2)Concerns about the steady supply of GGBFS;(3)Difficulties in evaluating the mitigating effects of GGBFS on early-age “thermal loading”.This paper reports on the methodology which is adopted to carry out this project. Special considerations are paid to issues associated with concrete early-age thermal contraction. Modelling of a case study of a commercial building in Shanghai is used to compare the cost effectiveness of using conventional crack control steel reinforcement only with the mitigation of thermal crack stresses by adopting GGBFS as a partial replacement for traditional cement. The study includes the use of finite element modelling to investigate the development of heat during the early age cement hydration process and the resulting thermal stresses produced in the concrete.

Application of Residual Rice Husk Ash from Vietnam as a Supplementary Cementitious Material in Concrete

The residual RHA from Vietnam is used to test the likely application in cement and concrete. The characteristics, quality and influence of RHA on the quality of concrete are investigated in this investigation. The workability, strength and durability of concrete added with ground RHA satisfy with the relevant standards and requirements. It indicates that the ground RHA in this study can be used as a good supplementary cementious material. Therefore, it is possible to obtain RHA concrete with comparable properties than those of the control specimen (without RHA) with a lower consumption of cement, thus reducing the CO2 emissions during the production of cement and the environmental and disposal problem of the ash can also be diminished. Moreover, while the results will be able to substantiate the viability of application of RHA in concrete industry under the prevailing conditions in Vietnam, they are also expected to be especially useful for future studies on RHA in a specific condition in this country.

Effect of Bauxsol on properties of cement pastes

This paper presents the results of an experimental investigation carried out to evaluate the influence of Bauxsol, an artificially neutralised bauxite refinery residue (NBRR), on various properties of cement pastes. It was found that the NBRR does not have any pozzolanic properties and hence cannot be used as a supplementary cementitious material in concrete. In order to evaluate the effect of adding the product to Portland cement (PC) pastes, fresh properties (i.e. standard consistency and slump), setting time and heat of hydration were measured. In addition, its influence on chemical changes and compressive strength was investigated. It was found that the addition of this NBRR resulted in a decrease in compressive strength beyond 7 days. The setting time decreased with an increase in NBRR content in PC pastes. The rate of heat evolution for NBRR pastes was greater than that of the PC pastes, but a corresponding increase in the quantity of calcium hydroxide was not found. Therefore, it was concluded that unidentified hydration products when Bauxsol was used in PC pastes might have been the reason for the decrease in setting times.

Testing and Evaluation on Fractal Characteristic of Cementing Materials Powder

The cement powder materials are evaluated by fractal theory. Fractal characteristic parameters are analysed and evaluated by the method of laser particle size analyzer, microscope, transmission electron microscope. In this paper, cement powder materials has good self-similarity. Fractal dimension of grading is tested and evaluated by laser particle size analyzer, fractal dimension of cluster is tested by microscope, fractal characteristic of particle distribution is tested by transmission electron microscope. Compared with traditional weight of screen residue and specific surface area, those methods are more careful. Fineness fractal parameters and activity of ultra fine fly ash and pulverized slag have good linear dependence relation that is evaluated by fractal dimensions. Fractal characteristics provide an important basis to further explore the inherent relation of cement powder materials and concrete material density effect.

Experimental Research on the Relationship between Dielectric Constant and Compressive Strength of Cement Concrete Materials

Dielectric constant is the most important material property which ground penetrating radar(GPR) data reflects. Based on experiment, through the determination of the compressive strength during concrete mixture ages and the real part and imaginary part of dielectric constant, the relationship between dielectric constant and the compressive strength of cement concrete material is studied. It is shown from the achievements that there has feasibility to non-destructively test the cement concrete material compressive strength by using GPR.

Performance Related Tests on Recycled Materials for Sustainable Design of Pavement Systems

Abstract This paper provides recommendations for performance-related tests to select recycled materials to be used in pavement foundations (base/sub-base layers). The test protocol presented in this paper will help transportation agencies, pavement design engineers and construction industry professionals to mechanistically evaluate and select sources of recycled hot-mix asphalt and portland cement concrete materials and identify factors that contribute most to the longevity of layers using recycled pavement materials. Extensive literature review was conducted on the aggregate specifications in the United States and other countries to identify the protocols used to evaluate the suitability of virgin and recycled aggregates in base and sub-base layers. The test procedures, typically designed for virgin aggregates, were modified to account for the recycled materials in the aggregate mix. The test procedures were further evaluated on the basis of mechanical performance, accuracy, practicality, complexity, precision, and test cost. The performance of the developed aggregate evaluation systems was determined through testing and analysis of 12 aggregates with different lithology and known field performance history. These samples were selected from seven states with different seasonal frost cycles. The performance tests were conducted and modifications were made to the tests procedures to better understand the mechanical behavior of aggregate systems with recycled materials. This study revealed that shear strength, toughness, abrasion, durability, and frost susceptibility influence the performance of the unbound aggregate layers. Statistical analysis of the data showed that shear strength of the aggregate systems has the most impact on the performance of the unbound systems consisted of recycled materials.