Mechanical Performance of Sprayed Engineered Cementitious Composite Using Wet-Mix Shotcreting Process for Repair Applications

2004 ◽  
Vol 101 (1) ◽  
2020 ◽  
Vol 47 (12) ◽  
pp. 1311-1319 ◽  
Author(s):  
Adeyemi Adesina ◽  
Sreekanta Das

Engineered cementitious composite (ECC) is conventionally made up of high content fly ash (FA) combined with Portland cement (PC) as a binder. However, the growing call for sustainability is leading to continuous decommissioning of various coal power plants around the world thereby limiting the supply of fly ash available for ECC production. Therefore, it is of high importance to find alternative materials that can be incorporated into ECC as a partial replacement of the conventional binders. This experimental investigation was carried out to investigate the feasibility of incorporating glass powder (GP) as binder into ECC mixtures. The mechanical performance in terms of its compressive, tensile, and flexural properties was evaluated. Results from this study showed that 25% FA can be replaced with GP without any significant reduction in the mechanical performance of ECC mixtures. Microstructural investigations of the mixtures incorporating GP show good bonding between the cementitious matrix and the fibres.


2019 ◽  
Vol 53 (28-30) ◽  
pp. 4285-4304 ◽  
Author(s):  
Alaa Mohammedameen ◽  
Abdulkadir Çevik ◽  
Radhwan Alzeebaree ◽  
Anıl Niş ◽  
Mehmet Eren Gülşan

Conventional concrete suffers from brittle failures under mechanical behaviour, and lack of ductility results in the loss of human life and property in earthquake zones. Therefore, the degree of ductility becomes significant in seismic regions. This paper investigates the influence of poly-vinyl alcohol fibers, basalt fiber-reinforced polymer (BFRP) and carbon fiber-reinforced polymer (CFRP) fabrics on the ductility and mechanical performance of low (LCFA) and high (HCFA) calcium fly ash-based engineered cementitious composite concrete. The study also focuses on the mechanical behaviour of the CFRP and BFRP materials using different matrix types exposed to 3.5% seawater environment. Cyclic loading and scanning electron microscopy observations were also performed to see the effect of chloride attack on mechanical performance and ductility of the specimens. In addition, utilization of CFRP and BFRP fabrics as a retrofit material is also evaluated. Results indicated that the degree of ductility and mechanical performance were found to be superior for the CFRP-engineered cementitious composite hybrid specimens under ambient environment, while LCFA-CFRP hybrid specimens showed better performance under seawater environment. The effect of matrix type was also found significant when engineered cementitious composite is used together with fiber-reinforced polymer materials. In addition, both fiber-reinforced polymer materials can be used as a retrofit material under seawater environment.


Author(s):  
Maninder Singh ◽  
◽  
Babita Saini ◽  
Chalak H.D. ◽  
◽  
...  

Generation of solid waste materials from various industrial sources is becoming a challenging issue for safe disposal. Durability performance of hydraulic structures under environmental loadings (aggressive substances) is also a concerning issue. The present paper investigated the durability performance of engineered cementitious composite (ECC) mortar containing stone slurry powder (SSP). SSP was used as partial subrogation of micro silica sand (MSS) and fine sand (FS) by 25% and 50% for each type of sand. Electrical resistivity (ER), compressive and tensile behaviour of various mixes were studied experimentally under chloride, sulphate and chloride-sulphate combined environmental conditions. Results obtained from various properties revealed that performance of fully MSS and FS containing ECC mixes was affected under aggressive substances at initial stages. The observations demonstrate that ECC containing SSP was durable and maintains better mechanical performance over fully MSS and FS containing mixes. This improvement finds a place in construction of hydraulic structures under aggressive environments.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4095
Author(s):  
Qing Chen ◽  
Zhiyuan Zhu ◽  
Rui Ma ◽  
Zhengwu Jiang ◽  
Yao Zhang ◽  
...  

In this paper, the mechanical performance of an ultra-high-performance concrete (UHPC) repaired cementitious composite system, including the old matrix and the new reinforcement (UHPC), under various high temperature levels (20 °C, 100 °C, 300 °C, and 500 °C) was studied. In this system, UHPC reinforced with different contents of steel fibers and polypropylene (PP) fibers was utilized. Moreover, the physical, compressive, bonding, and flexural behaviors of the UHPC repaired system after being exposed to different high temperatures were investigated. Meanwhile, X-ray diffraction (XRD), baseline evaluation test (BET), and scanning electron microscope (SEM) tests were conducted to analyze the effect of high temperature on the microstructural changes in a UHPC repaired cementitious composite system. Results indicate that the appearance of the bonded system changed, and its mass decreased slightly. The average percentage of residual mass of the system was 99.5%, 96%, and 94–95% at 100 °C, 300 °C, and 500 °C, respectively. The residual compressive strength, bonding strength, and flexural performance improved first and then deteriorated with the increase of temperature. When the temperature reached 500 °C, the compressive strength, bonding strength, and flexural strength decreased by about 20%, 30%, and 15% for the UHPC bonded system, respectively. Under high temperature, the original components of UHPC decreased and the pore structure deteriorated. The cumulative pore volume at 500 °C could reach more than three times that at room temperature (about 20 °C). The bonding showed obvious deterioration, and the interfacial structure became looser after exposure to high temperature.


2021 ◽  
Vol 245 ◽  
pp. 107601
Author(s):  
Zhanqi Cheng ◽  
Yuyang Hu ◽  
Liusheng Chu ◽  
Chengfang Yuan ◽  
Hu Feng

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