ORCID Profile
0000-0001-5161-4502
Current Organisation
Hong Kong Polytechnic University
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Publisher: Elsevier BV
Date: 02-2021
Publisher: SAGE Publications
Date: 03-07-2019
Abstract: Ultra-high-performance concrete is typically defined as an advanced cementitious material that has a compressive strength of over 150 MPa and superior durability. This article presents the development of a new type of ultra-high-performance concrete, namely, ultra-high-performance seawater sea-sand concrete. The development of ultra-high-performance seawater sea-sand concrete addresses the challenges associated with the shortage of freshwater, river-sand and coarse aggregate in producing concrete for a marine construction project. When used together with corrosion-resistant fibre-reinforced polymer composites, the durability of the resulting structures (i.e. hybrid fibre-reinforced polymer–ultra-high-performance seawater sea-sand concrete structures) in a harsh environment can be expected to be outstanding. The ultra-high strength of ultra-high-performance seawater sea-sand concrete and the unique characteristics of fibre-reinforced polymer composites also offer tremendous opportunities for optimization towards new forms of high-performance structures. An experimental study is presented in this article to demonstrate the concept and feasibility of ultra-high-performance seawater sea-sand concrete: ultra-high-performance seawater sea-sand concrete s les with a 28-day cube compressive strength of over 180 MPa were successfully produced the s les were made of seawater and sea-sand, but without steel fibres, and were cured at room temperature. The experimental programme also examined the effects of a number of relevant variables, including the types of sand, mixing water and curing water, among other parameters. The mini-slump spread, compressive strength and stress–strain curve of the specimens were measured to clarify the effects of experimental variables. The test results show that the use of seawater and sea-sand leads to a slight decrease in workability, density and modulus of elasticity it is also likely to slightly increase the early strength but to slightly decrease the strengths at 7 days and above. Compared with freshwater curing, the seawater curing method results in a slight decrease in elastic modulus and compressive strength.
Publisher: SAGE Publications
Date: 12-2018
Abstract: Extensive research has been conducted on the replacement of steel rebars with fibre-reinforced polymer rebars to eliminate the steel corrosion problem in conventional steel bar–reinforced concrete structures. However, as the performance of fibre-reinforced polymer rebars is substantially inferior in compression (due to issues such as fibre micro-buckling) than in tension, their use in concrete columns is generally not recommended this poses a significant challenge when a steel-free structure is needed. This article presents a novel steel-free hybrid rebar developed at The Hong Kong Polytechnic University that overcomes the above-mentioned problem. Such a hybrid rebar typically consists of a central fibre-reinforced polymer rebar, an external fibre-reinforced polymer confining tube and an annular layer of high-strength cementitious material such as ultrahigh-performance concrete. To demonstrate the performance of these hybrid rebars, results from a series of preliminary tests and associated modelling work are presented in the article. These results indicate that (1) the fibre-reinforced polymer rebar at the centre is well supported against bar buckling and fibre micro-buckling, (2) the compressive strength of the fibre-reinforced polymer material can be fully mobilized and (3) the stress–strain response of hybrid rebars can be designed to resemble an elastic–plastic response with some post-yielding hardening.
Publisher: SAGE Publications
Date: 20-10-2020
Abstract: The use of seawater and sea-sand in producing concrete has attracted increasing research attention in recent years to address the shortage of river sand and in certain applications the shortage of freshwater. In particular, reinforced concrete structures made of seawater sea-sand concrete (SSC) and corrosion-resistant fiber-reinforced polymer (FRP) are particularly attractive for the development of coastal and marine infrastructure (e.g. on remote islands) as durable structures can be created using locally available materials. Existing studies on SSC or seawater concrete have been largely limited to the use of mixing water with a salinity level close to the world-average ocean salinity. Against this background, the present paper reports the first ever systematic study on the effect of salinity of mixing water on the properties of concrete. The present study covered a wide range of salinity levels from 16.5 g/L to 82.5 g/L, and examined a wide range of short-term concrete properties including the heat of hydration, shrinkage, compressive strength and modulus of elasticity. The test results show that the salinity of mixing water has a considerable effect on the rate of hydration heat and shrinkage at early ages, as well as the cumulative release of hydration heat. It is also shown that the water salinity has a slight negative effect on the compressive strength and modulus of elasticity of concrete at ages older than 14 days.
No related grants have been discovered for Jin-Guang Teng.