scholarly journals Evaluating the bond strength of repair materials under harsh environmental loading

2021 ◽  
Author(s):  
Paul A. Kwiczala
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Environmental Loading ◽  
Repair Materials ◽  
Additional Testing ◽  
Aging Infrastructure ◽  
Infrastructure Repair ◽  
Slant Shear

When considering aging infrastructure, repair paths are often taken as a cheaper solution to extend the life the structure. Repair materials are selected for their sustained capacity to withstand the load. This study evaluated the durability of repair materials, based on the principles of engineered cementitious composites against traditional concrete mixes. The durability of the repair materials was evaluated through a comprehensive testing regime which evaluated the performance of the materials in isolation as well as in combination with a prescribed substrate. While the SCM based repair mixes withstood durability tests comparability and did outperform the reference concrete, the improvement wasn’t significant enough to justify the costs associated. The slant shear method may not be the optimal way to measure bond strength as a valid result is greatly dependent on the ratio of bond to compressive strength for the mix in question. Additional testing is recommended.

scholarly journals Evaluating the bond strength of repair materials under harsh environmental loading

2021 ◽  
Author(s):  
Paul A. Kwiczala
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Environmental Loading ◽  
Repair Materials ◽  
Additional Testing ◽  
Aging Infrastructure ◽  
Infrastructure Repair ◽  
Slant Shear

When considering aging infrastructure, repair paths are often taken as a cheaper solution to extend the life the structure. Repair materials are selected for their sustained capacity to withstand the load. This study evaluated the durability of repair materials, based on the principles of engineered cementitious composites against traditional concrete mixes. The durability of the repair materials was evaluated through a comprehensive testing regime which evaluated the performance of the materials in isolation as well as in combination with a prescribed substrate. While the SCM based repair mixes withstood durability tests comparability and did outperform the reference concrete, the improvement wasn’t significant enough to justify the costs associated. The slant shear method may not be the optimal way to measure bond strength as a valid result is greatly dependent on the ratio of bond to compressive strength for the mix in question. Additional testing is recommended.

Mechanical Properties of Modified Engineered Cementitious Composites (MECC) Incorporating Marble Dust

2021 ◽  
Vol 9 (8) ◽  
pp. 1140-1146
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Bottom Surface ◽  
Cementitious Composites ◽  
Strength Development ◽  
Shape Effect ◽  
Main Concern ◽  
Engineered Cementitious Composites ◽  
Flexure Strength ◽  
Marble Dust

Engineered cementitious composites (ECC) are a type of high-performance fiber reinforced cementitious composite. ECC has different applications in the construction field due to its inherent characteristics of high tensile strain. The main concern regarding ECC is its high cost. The content of cement is high contributing to its cost. In this research work, the cement in ECC is replaced with marble dust and its mechanical properties such as compressive strength and flexure strength have been assessed. For this purpose, both cubes and cylinders were tested at different test ages for finding the compressive strength development with time and observe the shape effect of specimens on the compressive strength of ECC mixes. Beam members were tested for finding the flexure strength of ECC mixes. Deflection gauge was also installed at the mid span on the bottom surface of the beams to find the maximum mid span deflection before failure. The compression test results of both cylinders and cubes revealed that using of marble dust has negative effect on the compressive strength of ECC. The flexure strength result showed that marble dust can be used up to some extent replacing cement will increase the flexure strength. The result of mid span deflection suggests that by incorporating marble dust in ECC, its ductility increases.

Mechanical Performances of Green Engineered Cementitious Composites Incorporating Various Types of Sand

2019 ◽  
Vol 821 ◽  
pp. 512-517
Author(s):  
Siong Wee Lee ◽  
Chai Lian Oh ◽  
Mohd Raizamzamani Md Zain ◽  
Norrul Azmi Yahya ◽  
Azerai Ali Rahman
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Cementitious Composites ◽  
Flexural Stress ◽  
Engineered Cementitious Composites ◽  
River Sand ◽  
Granulated Blast Furnace Slag ◽  
In Series ◽  
Mechanical Performances ◽  
Flexural Tests

This paper evaluates the mechanical performances of green engineered cementitious composites (ECC) by means of compressive strength and flexural behaviour. Green ECC made of cement, ground granulated blast-furnace slag (GGBS), river sand or recycled concrete fine (RCF), polypropylene (PP) fiber, water and superplasticizer (SP) was employed in this study. Compression test result implies that green ECC incorporating either sieved river sand or sieved RCF (below 600 μm) in series G60 and G70 exhibited greater compressive strength compared with green ECC with unsieved river sand. In series G80, compressive strength of green ECC was not affected by RCF content. Flexural stress-mid deflection curves demonstrated that all green ECC specimens performed more ductile compared to normal concrete as they undergone large deformation capacity after the first cracking strength. Both compression and flexural tests suggested that mixture G80SRCF0.4 containing large amount of sieved RCF and least amount of cement is the best green ECC mixture in this study.

Retrofitting Bond of Damaged Concrete Surface in Harbour Structures

2013 ◽  
Vol 684 ◽  
pp. 177-181
Author(s):  
Alireza Ghaffari ◽  
Amirreza Ghaffari
Keyword(s):  
Bond Strength ◽  
Silica Fume ◽  
Coarse Aggregate ◽  
Sea Water ◽  
Concrete Surface ◽  
Fine Aggregate ◽  
Water Pool ◽  
Repair Materials ◽  
Steel Bars ◽  
Slant Shear

An experimental research of the bonds amongst retrofitted materials on concrete structures under seashore climate has conducted. The strength of a bond between repair materials and concrete substratum has been assessed on the base of slant shear test experiment. In this research 52 samples has prepared and used for experiment .The fresh concrete with fine aggregate mix only (less than 9mm particle size without coarse aggregate) and 14% silica fume by weight of cement (normally 8 to 10% but 14% because of high amount of fine aggregate ) added to the mix which improve the properties of concrete such as bond strength as well as compressive strength and reduces permeability of sea water in corrosion or deterioration of steel bars by protecting reinforcing steel from erosion (pivotal aim of research) and even reduces abrasion resistance .Therefore silica fume was rolled an essential repairer materials on seashore structures. The retrofitted specimens were cured on water pool and kept on the seashore simulation climate upto required curing times . The strength of the improved samples has studied in three aspects as bond strength according surface roughness ,curing periods and concrete additives like silica fumes and fibres .

scholarly journals The Effect of Elevated Temperature on Engineered Cementitious Composite Microstructural Behavior: An Overview

2022 ◽  
Vol 30 (1) ◽  
pp. 433-449
Author(s):  
Mohamad Hakimin Khazani ◽  
Oh Chai Lian ◽  
Lee Siong Wee ◽  
Mohd Raizamzamani Md Zain ◽  
Norrul Azmi Yahya
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Scientific Publications ◽  
The Past ◽  
Micro Cracks ◽  
Bibliographic Data ◽  
Literature Reviews ◽  
Microstructural Behavior

This paper discusses the quantitative bibliographic data derived from scientific publications on Engineered Cementitious Composites (ECC) subjected to elevated temperature, the influence of elevated temperature on the mechanical properties, particularly the compressive strength and microstructure behavior of Engineered Cementitious Composites (ECC) mixtures based on the review of previous pieces of literature. Systematic literature reviews were employed as the methodology in this study. The age of related publications selected to be reviewed was limited to publications for the past ten years, 2010 to December 2020. It was found from available research that exposure of the ECC specimen at the elevated temperature starting from 200oC significantly reduced the compressive strength when the temperature increases, melting of fiber and increase of porosity causes the dramatically increase micro-cracks.

scholarly journals Development of Engineered Cementitious Composites Using Sea Sand and Metakaolin

2021 ◽  
Vol 8 ◽  
Author(s):  
Qiyao Yao ◽  
Zuo Li ◽  
Chenyu Lu ◽  
Linxin Peng ◽  
Yuejing Luo ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fracture Energy ◽  
Tensile Strain ◽  
Chloride Ions ◽  
Silica Sand ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Strain Capacity ◽  
Sea Sand ◽  
Tensile Strain Capacity

The present study investigates the possibility of using sea sand, instead of silica sand, in producing engineered cementitious composites (ECCs) and the optimal mix proportion, mechanical behavior, and erosive effect of chloride ions on sea sand ECCs (SECCs). Nine groups of SECC specimens were prepared based on the orthogonal test design, and these cured for the uniaxial tensile, uniaxial compression, and fracture energy tests. The roundness and sphericity of sea sand and silica sand were quantified by digital microscopy. The microstructure and composition of SECCs were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mix proportions of SECCs with a tensile strain capacity more than 2% and a compressive strength more than 60 MPa were obtained. The factor analysis of these serial tests revealed that the contents of both fly ash and sea sand have a significant effect on the compressive strength and tensile strain capacity of SECCs. The fracture energy test revealed that the matrix fracture toughness of SECCs significantly increases with the increase in sea sand content. The XRD analysis revealed that the addition of metakaolin can enhance the ability of SECCs to bind chloride ions, and with the increase in chloride ion content, the ability of SECCs to bind chloride ions would improve. The results of the present study provide further evidence of the feasibility of using sea sand in the production of ECCs, in order to meet the requirements of diverse concrete components on ductility and durability.

scholarly journals Non Destructive Studies on Engineered Cementitious Composites using Microsilica & Polypropylene Fibre

2019 ◽  
Vol 8 (2S5) ◽  
pp. 18-21
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Admixture ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Polypropylene Fibres ◽  
Curing Regimes ◽  
Non Destructive

This study focuses on assessing the durability property of engineered cementitious composites using Ultrasonic pulse velocity method (direct and semi direct) to compute the compressive strength. Even the effect of mineral admixture on the mortar properties for different curing regimes shall be determined using this method. Mortar specimens containing microsilica in different percentages ranging from 5% to 25%, replacing portland cement by weight and adding polypropylene fibres ranging from 0.5% to 2% are chosen for evaluation. 20% of microsilica and 2% of polypropylene fibres induced to increase the range of UPV from 3463 m/s to 3505 m/s for 7 and 28 day curing regimes and also the compressive strength significantly improved for the above constituent. However there was a marginal decrease in the compressive strength and UPV outcomes when cement is replaced by microsilica greater than 20%. A relationship had been framed between ultrasound pulse velocity and compressive strength.

Properties Evaluation of Repair Mortars Containing EVA and VA/VeoVa Polymer Powders

2017 ◽  
Vol 25 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
Cheng-Hao Li
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Bond Strength ◽  
Drying Shrinkage ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Repair Materials ◽  
Repair Mortars

The repair of damaged structures is a complicated problem in the construction industry and it is no uniform standard for evaluating the effectiveness of repair materials. Two different redispersible polymer powders, ethylene vinyl acetate (EVA) and polyvinyl acetate-vinyl carboxylate (VA/VeoVa), were added in the repair mortars with two water-cement ratios and three polymer-cement ratios. The effectiveness of repair materials was evaluated according to the physical, mechanical properties and micrographs. Testing program includes setting time, drying shrinkage, thermal expansion, compressive strength, tensile strength, flexural strength, bond strength, X-ray diffraction analysis, scanning electron microscopy observation. Test results show that the specimens with VA/VeoVa and w/c of 0.5 have highest compressive strength, tensile strength, flexural strength and bond strength. The specimen with EVA also has higher strength than control one at the age of 28 days. The drying shrinkage deformation of VA/VeoVa specimen is close to the control one. The specimens with VA/VeoVa have lower thermal expansion than EVA specimen when the water-cement ratio is 0.5 and there is no difference between EVA and VA/VeoVa specimens for the water-cement ratio of 0.6. The micrographs show that adding polymer powder can reduce the pore and improve the durability.

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