Detection of setting time in cement hydration using patch antenna sensor

Abstract

The dielectric constant of cement will decrease with an increase of moisture content, resulting in an increasing fundamental resonant frequency of a covered patch antenna. Based on this principle, the authors utilized a patchantenna sensor to determine the initial and final setting time of cement during hydration by sensing the variation of moisture content. The theory of an equivalent dielectric constant model was adopted to exhibit the relationship between the fundamental resonant frequency of a buried antenna sensor and a dielectric constant in the covering cement paste. The phenomenon is then verified by both simulation in a high frequency structure simulator (HFSS) and experiments. The initial setting time of cement is regarded as the moment

Graphene oxide-incorporated cementitious composites: a thorough investigation

“…92 The initial setting time refers to the time when cement paste starts losing its plasticity. 93 If the initial setting time of cement is X minutes, the mortar should be placed in the desired position within X minutes of adding water. The mortar will lose its optimum strength if the process is delayed.…”

“…The initial setting time of the paste was measured using the Vicat needle test in accordance with ASTM C191 [92]. Initial setting time refers to the time when cement paste starts losing its plasticity [93]. If the initial setting time of cement is X minutes, the mortar should be placed in the desired position within X minutes of adding water.…”

Mitigating the Effect of Rapid Hydration of Fresh Concrete in Hot Weather Climate Using Gum Arabic Powder as a Setting Time Retarder Admixture

“…Stiffening of the cement and Gum-Arabic paste when hydration begins according to EN196-3-2016 (European building code) it is basically measured in the laboratory using a Vicat apparatus which records the penetration of a needle into the paste, the time taken for a particular penetration is the required setting time (Yi et al, 2021). The recorded time at 3.4MPa resistance of the needle is known at the initial setting time at this point the plasticity of the paste is lost (Yi et al, 2021), according to BS12 this time is not less than 45minutes for an ordinary Portland cement. The final setting time is achieved when the cement has up to 27.6MPa of penetration resistance, this time is not more than 10 hours in accordance with BS12.…”

An off-center fed patch antenna with overlapping sub-patch for simultaneous crack and temperature sensing

“…In addition, the antenna's electromagnetic waves can penetrate non-metal coverings, making antenna-based sensing technology better suited for structural health monitoring. Various antenna-based sensors have been proposed for many tasks, including strain sensing [18][19][20], crack sensing [21], displacement sensing [22][23][24], temperature sensing [25], humidity sensing [26], bolt loosening detection [27], and cement hydration setting time detection [28]. Some early antenna-based sensors only tracked the change of a single physical variable.…”