Effect of Amount of Fibre and Damage Level on Service Life of SFR Recycled Concrete in Aggressive Environment

Abstract

The paper presents a numerical calculation of the service life of concrete structures considering the effect of chlorides in the case of the material properties of structural lightweight waste aggregate concrete. Different amounts of fibres (0.0%, 1.0%, and 1.5%) and different values of compressive preloading (0%, 50%, and 100% of the ultimate strength capacity-USC) were considered. The subject of the research was the comparison of the influence of the constant diffusion coefficient and the time-dependent diffusion coefficient regarding the service life of the selected structure. Nine groups of material characteristics in combination with two numerical models are compared. A time-dependent diffusion coefficient and maturation coefficient, which were determined based on long-term monitoring (up to 461 days), were accepted for the numerical modelling. Thanks to time-dependent parameters, it is possible to observe the results of the theoretical service life of the structure and the influence of the mentioned factors. The analysed structure can be considered as the upper layer of an industrial floor in a chemical plant. It is important to determine the theoretical service life at which the structure shall be inspected or replaced. The results, in general, show that a higher amount of fibres reduces the service life as well as the preloading of the structure. An exception was a mixture with 1% of fibre loaded to 50% USC, which shows a lower diffusion coefficient than the specimens without preloading.

Strain Hardening of Polypropylene Microfiber Reinforced Composite Based on Alkali-Activated Slag Matrix

“…Development of new strain-hardening inorganic composite can be in mixture composition and in manufacturing technology. In study of mixture compositions the following results were obtained: the use of microfiber in the amount of 2% by volume or more [51][52][53][54][55]; the use of rheologically active mineral additives in cement matrices with a superplasticizer to ensure workability at low W/C ratio and at high microfiber amount [56,57]; the use of mineral additives that improve workability and setting time in alkali-activated slag matrices [58][59][60][61]; the use of quartz sand with a low fineness modulus as a fine aggregate to obtain a homogeneous matrix and ensure a dense and uniform contact of matrix with the microfiber surface [62][63][64][65][66][67][68]. Manufacturing technology takes into account: the sequence of addition of components into a mixture [69][70][71][72][73]; mixing modes [62,[74][75][76][77].…”

Analysis of Measured Parameters in Relation to the Amount of Fibre in Lightweight Red Ceramic Waste Aggregate Concrete

“…Dynamic modulus of elasticity was measured by the non-destructive testing method (NDT) also 28 days after casting. The surface resistivity of concrete was measured in the specific points of time after casting-7, 14, 28, 56, 91 days-to calculate the diffusion and ageing coefficient, and almost a year after casting for the research purposes of the relationship between surface and bulk resistivity [35,36]. The methods are also briefly introduced in this contribution.…”

Fiber-Type Influence on the Flexural Behavior of RC Two-Way Slabs with an Opening

“…Petr L. and Marie H. [15] presented a numerical study of concrete samples exposed to chlorides, in relation to the service life of lightweight waste structural members. The study used different types of waste material to produce lightweight concrete, such as red clay and red ceramics, with steel fiber at different percentages.…”