Investigation of Critical Quality Assurance Parameter Variations for Concrete

1997 ◽  
Vol 1575 (1) ◽  
pp. 92-101
Author(s):  
Richard K. Smutzer ◽  
Sedat Gulen ◽  
Youlanda K. Belew ◽  
Virgil L. Anderson
Keyword(s):  
High Pressure ◽  
Quality Assurance ◽  
Flexural Strength ◽  
Concrete Strength ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Army Corps ◽  
Split Tensile Strength ◽  
Air Content ◽  
Concrete Mix

The Indiana Department of Transportation is involved in preparing statistically sound specifications for strong and durable concrete used in quality assurance programs. Previous laboratory studies relating concrete strength to air content and concrete mix designs dealt with variation in compressive strength. This study searched for a statistically sound relationship between air content, concrete mix designs, and flexural strength. This study also developed a high-pressure method of hardened concrete air content determination. Sixty-four independent batches (combinations) of concrete were produced, each batch was subjected to a total of 24 tests—4 plastic and 20 hardened. The design factors were aggregate type and gradation, plastic air content, cement, and pozzolanic content and testing operator. After plastic testing, three flexural strength beams were cast from each batch of concrete. The experimental design response variables consisted of flexural, compressive, and split tensile strength along with pulse velocity. Analysis of variances, indicated that the optimum flexural strength could be obtained using as-received stone course aggregate and an air content of between 6 percent and 7.9 percent, with no fly ash. A high-pressure air meter, similar to the meter developed by the Army Corps of Engineers, was used. A strong statistical correlation of determination, r2 = 0.94, was obtained between plastic and the hardened concrete air content using this meter.

scholarly journals An Experimental Investigation on the Strength Properties of Self Curing Concrete by Using Super Absorbrnt Polymer

2019 ◽  
pp. 634-643
Author(s):  
V. Veera Mohan Reddy ◽  
K. Mohammed Rasheed
Keyword(s):  
Flexural Strength ◽  
Fresh Concrete ◽  
Concrete Strength ◽  
Plain Concrete ◽  
Hardened Concrete ◽  
Split Tensile Strength ◽  
Super Absorbent Polymer ◽  
Positive Effects ◽  
Internal Water ◽  
Absorbent Polymer

The super absorbent polymer (SAP) has the nature of absorbing large amount of water and converts into gel and at the same time it swells or a large amount of volume change occurs when SAP reacted with water. Main SAP agent is sodium polyacrylate . These properties are very useful and effective in plain concrete. It is proved that it has many positive effects on the properties of concrete in both stages; 1.fresh concrete, 2. hardened concrete. Super absorbent polymer is mainly having the water tightness properties of plain concrete with time. The study includes short term and long term effect of the super absorbent polymer on the water sealing properties. Many advantages exist in the use of super absorbent polymer in plain concrete with internal water. This internal water source acts as internal curing agent after the final setting of concrete. At the same time the SAP releases water at relatively slower rate at the fresh concrete stage. The SAP also provides additional voids in the concrete. These voids affect the concrete strength negatively at the same time improve the concrete performance by improving the concrete workability and consistency, reducing the concrete susceptibility to freezing thawing cycle, and improving concrete stability. In this project we tried to study the behavior of super absorbent polymer in mechanical properties of compression, split tensile and flexural strength with internally cured concrete. An experiment has been carried out for M50 concrete using Super absorbent polymer of 0%,0.2%,0.3%,0.4% and 0.5% respectively. concrete cubes, cylinders and beams are casted and tested for 7 days and 28 days. The results are discussed in detailed and the compressive strength and split tensile strength greater for 0.2% of sap when compared with the remaining percentages of sap concrete. 0.2% of sap is optimum for the Beam of size 700X150X150 mm and shows the high flexural strength.

scholarly journals INFLUENCE OF VISCOSITY MODIFYING AGENT ON SOME RHEOLOGICAL PROPERTIES, SEGREGATION RESISTANCE AND COMPRESSIVE STRENGTH OF SELF-COMPACTING CONCRETE

2013 ◽  
Vol 19 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Anna M. Grabiec
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Concrete Strength ◽  
Vertical Direction ◽  
Reference Level ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Modifying Agent ◽  
Air Content ◽  
Concrete Mix

Rheological properties of self-compacting concrete mixes containing a viscosity modifying agent (VMA) in their composition were studied. After preliminary studies self-compacting concrete mixes and, particularly, a fluid concrete mix prone to segregation of its ingredients were chosen. VMA was added in various amounts to that concrete mix to check how it performed in fresh and hardened concrete. Main studies focused on the influence of VMA on the following properties of concrete mixes: the slump flow, the flow time into the diameter of 500 mm and the resistance to segregation in the vertical direction. Moreover, the air content of concrete mixes and the 28-day compressive strength of concrete were measured. Test results showed that VMA significantly influenced the rheological properties of concrete mix, stabilised it and reduced the segregation. It was proved, that the concrete mix modified by VMA used in the optimal amount, featured the smallest scatter of concrete strength results. Besides, the Tukey's test showed that a reduction of the concrete compressive strength is possible to be statistically insignificant when compared to the reference level.

A sustainable approach in using construction and demolition waste materials in concrete

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pritish Gupta Quedou ◽  
Eric Wirquin ◽  
Chandradeo Bokhoree
Keyword(s):  
Flexural Strength ◽  
Pulse Velocity ◽  
Chloride Penetration ◽  
Construction And Demolition Waste ◽  
Waste Materials ◽  
Hardened Concrete ◽  
Depth Of Penetration ◽  
Demolition Waste ◽  
Continuous Increase ◽  
Content Type

Purpose The purpose of this paper is to investigate the potential use of construction and demolition waste materials (C&DWM) as an alternative for natural fine aggregates (NFA), in view to solve the disposal problems caused due to landfills. In addition, to evaluate its suitability as a sustainable material, mechanical and durability properties have been performed on different proportions of concrete blending and the results recorded were compared with the reference concrete values. Design/methodology/approach In this research, the NFA were replaced at the proportion of 25%, 50%, 75% and 100% of C&DWM with a constant slump range of 130 mm–150 mm. This parameter will assess the consistency of the fresh concrete during transportation process. The characteristics of the end product was evaluated through various tests conducted on hardened concrete samples, namely, compressive strength, flexural strength, depth of penetration of water under pressure, rapid chloride penetration test, carbonation test and ultrasonic pulse velocity (UPV) test. All results recorded were compared with the reference concrete values. Findings The results demonstrated that the use of C&DWM in concrete portrayed prospective characteristics that could eventually change the concept of sustainable concrete. It was noted that the compressive and flexural strength decreased with the addition of C&DWM, but nevertheless, a continuous increase in strength was observed with an increase in curing period. Moreover, the increase in rapid chloride penetration and decrease in UPV over time period suggested that the concrete structure has improved in terms of compactness, thus giving rise to a less permeable concrete. The mechanical tests showed little discrepancies in the final results when compared to reference concrete. Therefore, it is opined that C&DWM can be used effectively in concrete. Originality/value This study explores the possible utilisation of C&DWM as a suitable surrogative materials in concrete in a practical perspective, where the slump parameter will be kept constant throughout the experimental process. Moreover, research on this method is very limited and is yet to be elaborated in-depth. This approach will encourage the use of C&DWM in the construction sector and in the same time minimise the disposal problems caused due to in landfills.

scholarly journals The Use of Fragmented, Worn-Out Car Side Windows as an Aggregate for Cementitious Composites

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1467 ◽  
Author(s):  
Maciej Szeląg ◽  
Bartosz Zegardło ◽  
Wojciech Andrzejuk
Keyword(s):  
Water Resistance ◽  
Microscopic Analysis ◽  
Hardened Concrete ◽  
Side Window ◽  
Recycled Glass ◽  
Air Content ◽  
Concrete Production ◽  
Concrete Mix ◽  
Glass Aggregate ◽  
Composite Samples

The paper describes a new model of concrete production, which contains a glass cullet. A worn-out car side window have been used for the production of recycled glass aggregate (RGA) and its properties were examined. The RGA was used in concrete as a 50% and 100% mass substitute of the traditional aggregate. Basic tests of fresh concrete mix and hardened concrete were carried out. The consistency, the air content in the concrete mix, the density of hardened concrete, water absorption, water resistance, frost resistance, and the compressive strength (after 9, 28, and 90 days) were evaluated. Composite samples were also subjected to microscopic analysis. The results showed that the RGA can be recommended as an aggregate for concretes, and the features of the RGA concrete are more favorable than those of traditional concrete. The microscopic analyses allowed us to identify the reasons for improving the properties of the RGA composites.

scholarly journals Utilization of PET Fiber in Concrete

2019 ◽  
pp. 204-212
Keyword(s):  
Flexural Strength ◽  
Fiber Reinforced Concrete ◽  
Fine Aggregate ◽  
Fiber Volume ◽  
Split Tensile Strength ◽  
Pet Bottles ◽  
Curing Period ◽  
Daunting Task ◽  
Concrete Mix ◽  
Pet Fibers

In this study, the effectiveness of waste Polyethylene Terephthalate (PET) fibers in improving the properties of concrete was investigated. Recycling of waste PET bottles is a daunting task in developing countries due to inadequate recycling facilities. The main aim of this research paper is to investigate the mechanical behavior of the components by using PET fibers. This paper describes the performance of PET fiber reinforced concrete for two grades of concrete mix M20 and M30. An experimental work has been carried out on the specimens like cubes, cylinders and beams which were casted in the laboratory and their behavior under the test was observed. The PET fibers were replaced to the fine aggregate volume from 0.0% to 2.0%. The compressive strength, split tensile strength and flexural strength of concrete were determined after 28 days of curing period. The highest compressive, split tensile and flexural strength of concrete was observed at 1.5% fiber volume replacement to the fine aggregate. The study concludes that the replacement of waste PET fibers to fine aggregate in concrete serves as a means of utilizing the waste generated by PET bottles to increase the strength of concrete.

scholarly journals Analysis of concrete strength determination methods for additive manufacturing

2021 ◽  
Vol 23 (2) ◽  
pp. 87-95
Author(s):  
E. A. Sorokina ◽  
N. O. Kopanitsa
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Concrete Strength ◽  
Strength Properties ◽  
Strength Analysis ◽  
Hardened Concrete ◽  
Russian State Standard ◽  
Concrete Mix ◽  
Concrete Quality ◽  
Property Control

The property control of concrete mix and hardened concrete is an integral part of the construction process. With the development of additive manufacturing in construction, the methods of assessing the properties of concrete mix and concrete are characterized by the formation of their structure and properties in concrete laying and curing. Currently, there is no regulatory documentation on a reliable assessment of the concrete mix and concrete quality for additive manufacturing. The purpose of this work is to propose a method for determining the concrete strength for additive manufacturing. The proposed concrete mix composition matches the technological requirements for 3D printing equipment and possesses the required properties. The concrete strength analysis and research methods are carried out in accord with the Russian State Standard. The paper describes the main problems of the concrete quality control in using additive manufacturing and proposes methods for determining the concrete strength properties for 3D printing.

scholarly journals Performance Evaluation of Cementitious Composites Incorporating Nano Graphite Platelets as Additive Carbon Material

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 290
Author(s):  
Farhan Ahmad ◽  
Arshad Jamal ◽  
Mudassir Iqbal ◽  
Muwaffaq Alqurashi ◽  
Meshal Almoshaogeh ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Water Absorption ◽  
Microstructural Analysis ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cementitious Composites ◽  
Air Content ◽  
Mechanical Durability ◽  
Huge Impact

Nano graphite platelets (NGPs) belong to the carbon family and have a huge impact on the construction industry. NGPs are used as multi-functional fillers and have the potential to develop reinforcing within cementitious composites. In this paper, NGPs were incorporated in cementitious composites to investigate the effects of NGPs on the fresh, mechanical, durability, and microstructural properties of concrete. Five mixes were prepared with intrusion of NGPs (0%, 0.5%, 1.5%, 3%, and 5% by weight of cement). The properties studied involved workability, air content, hardened density, compressive strength, tensile strength, flexural strength, sorptivity, ultrasonic pulse velocity (UPV), water absorption, and external sulfate attack. The workability and percent air content decrease by 22.5% and 33.8%, respectively, for concrete with 5% NGPs compared to the control mix. The specimens containing 5% of NGPs revealed the hardened density, compressive, tensile, and flexural strength to increase by 11.4%, 38.5%, 31.6%, and 44.34%, respectively, compared to the control mix. The results revealed that the incorporation of 5%NGPs in cementitious composites reduces the sorptivity and water absorption by 32.2% and 73.9%, respectively, whereas, it increases the UPV value by 7.5% compared to the control mix. Furthermore, the incorporation of NGPs provided better resistance against external sulfate attacks. SEM–EDX spectroscopy was carried out to investigate its microstructural analysis.

Symbiotic Outcomes of Potency and Microstructure on Nano Composite with Microsilica and Nanosilica Additives

2019 ◽  
Vol 57 ◽  
pp. 105-116 ◽  
Author(s):  
Swetha Madhusudanan ◽  
Lilly Rose Amirtham ◽  
S. Nallusamy
Keyword(s):  
Flexural Strength ◽  
Compression Strength ◽  
World Wide ◽  
Concrete Mixture ◽  
Hardened Concrete ◽  
Nano Materials ◽  
Normal Concrete ◽  
Nano Composite ◽  
Maximum Compression ◽  
Concrete Mix

Development and promotion of nano materials and technology has gained more attention of research scholars world wide spreding to different disciplines. In this research an approach has been made to study and investigate the behavioural properties and examine the microstuructural qualities of nano composite bricks replacing the cement with microsilica (mS) and nanosilica (nS) additives. The investigation was conducted using four types of specimens being normal concrete mixture with 0% of mS and nS, with 5%, 6% and 7% of mS, with 1%, 1.5% and, 2% of nS and replacing the cement with mixure of 5%+1%, 6%+1.5% and 7%+2% of mS and nS respectively. The results showed that, the maximum compression strength of 27.62MPa and 37.67MPa with the maximum flexural strength of 22.76MPa and 33.56MPa were possible when 6% of mS and 1.5% of nS were replaced respectively. Also, it was found that the maximum compression strength of 31.47MPa and flexural strength of 31.95MPa were achieved when we add 6%+1.5% mS and nS was added together in the concrete mix. The Scanning Electron Microscope (SEM) results revealed that, the mixture of mS and nS enhances the mechanical properties and the addition of mS and nS gives more symbiotic effects of densifying the microstructure in the hardened concrete mixture leading to better harmonic effects on durability.

scholarly journals Durability Evaluation of Concrete with Multiadmixtures under Salt Freeze-Thaw Cycles Based on Surface Resistivity

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Shibin Luo ◽  
Wei Liang ◽  
Hua Wang ◽  
Wensheng Wang ◽  
Rongjun Zou
Keyword(s):  
Flexural Strength ◽  
Concrete Strength ◽  
Air Entrainment ◽  
Surface Resistivity ◽  
Mineral Admixtures ◽  
Chloride Permeability ◽  
Freeze Thaw ◽  
Air Content ◽  
Rapid Chloride Permeability ◽  
Function Relationship

According to the climatic characteristics of seasonal frozen area in northeast China, the concrete strength tests, surface resistivity, rapid chloride permeability, and freeze-thaw test under salt solution were carried out to study the influences of mineral admixtures and air content on the conventional properties and salt freeze-thaw resistance of concretes. Then, the correlation analysis of surface resistivity with strength and rapid chloride permeability were further investigated. Subsequently, the changes of cumulative mass loss and relative dynamic elastic modulus varying with salt freeze-thaw cycles were analyzed to study the influences of mineral admixtures and air content on salt freeze-thaw resistance of concrete. The test results showed that fly ash (FA) was not conducive to improve the strength and salt freeze-thaw resistance of concrete. However, blast furnace slag (BFS) and silica fume (SF) could improve the compressive and flexural strength of concrete, in which SF can improve its strength more significantly. Increasing the air content of concrete will lead to the reduction of its compressive strength, and the flexural strength first increased and then decreased. Nevertheless, the addition of air-entrainment agent (AEA) has the best effect on improving the salt freeze-thaw resistance of concrete. Moreover, surface resistivity of concrete has a good exponential function relationship with strength and a good power function relationship with rapid chloride permeability. Therefore, it is of great significance for engineering quality control and quickly and nondestructive testing.

The Effect of Concrete Mix Proportion to the Air Bubble Spacing Coefficients of Hardened Concrete

2017 ◽  
Vol 726 ◽  
pp. 537-541
Author(s):  
Yang Wang ◽  
Hui Chao Liang ◽  
Bao Cheng Zhao ◽  
Yu Chuan Jiang
Keyword(s):  
Frost Resistance ◽  
Influence Factor ◽  
Fresh Concrete ◽  
Important Influence ◽  
Hardened Concrete ◽  
Air Bubble ◽  
Air Content ◽  
Mix Proportion ◽  
Concrete Mix

A large number of studies have shown that the air content of fresh concrete and the air bubble spacing coefficients of hardened concrete can be used to characterize the frost resistance of concrete. The performance of air-entraining agent is an important influence factor of these two indexes, and the effect of concrete mix proportion cannot be ignored. In this paper, the effect of concrete mix proportion to the air bubble spacing coefficients of hardened concrete has been studied through a series of tests.

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