Study of the possibility of using modiﬁed ﬁne fraction obtained from recycled concrete rubble as cement additive

Rajczyk, K.; Janus, Grzegorz; Kaliciak, Agnieszka

doi:10.32047/cwb.2019.24.3.188

Cited by 2 publications

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“…Furthermore, in order to maximize the use of secondary raw materials in line with the sustainable development policy, the applicability of an aggregate consisting of processed concrete production waste, additionally supplemented with selective demolition rubble, was investigated. The use of recycled concrete aggregate has been described in the PN-EN 206+A1:2016-12 standard, as well as in numerous studies (53)(54)(55)(56)(57)(58). Both the standard and some of the cited literature discourage the use of the 0÷4 mm fraction due to its high water demand and the resulting rapid decrease in the workability of concrete mixes.…”

Section: Discussionmentioning

confidence: 99%

Utilization of ground waste glass cullet in the industrial production of precast concrete elements

2021

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In the study, a field trial was carried out to evaluate the applicability of ground waste glass cullet as a binder component, in the industrial production of precast concrete elements. The influence of glass cullet addition on the properties of fresh and hardened concretes was compared to siliceous fly ash. Moreover, the effects of a partial substitution of the natural aggregate with recycled concrete and expanded clay aggregate were determined. The compressive strength of concretes, in which 25% of cement was substituted with ground waste glass cullet, was even 20% higher compared to elements with an analogous addition of siliceous fly ash. Over 56 days, no drops in strength related to the harmful effects of the alkali-silica reaction were observed. Replacing half of the natural aggregate with graded recycled concrete aggregate, allowed to lower the thermal conductivity of the walls by approx. 10%, with no negative impact on the compressive strength of precast elements. However, a decrease in the consistency of fresh mix was observed after 30 minutes. Replacing the 2÷8 mm gravel with the same fraction of expanded clay resulted in an approx. 18% decrease in thermal conductivity, while maintaining satisfactory mechanical properties. It was concluded that ground waste glass cullet can be successfully used as a fly ash replacement in the production of precast concrete elements.

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Section: Discussionmentioning

confidence: 99%

Utilization of ground waste glass cullet in the industrial production of precast concrete elements

2021

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Recycling of a Concrete Pavement after over 80 Years in Service

Rudnicki

Jurczak

2020

Materials

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This article presents the results of fatigue testing and assessment of the mechanical and physical properties of the concrete pavement of the A6 motorway, which was put in service in 1938. After 82 years of operation under heavy traffic loading conditions, the pavement was fully recycled by crushing of the existing concrete and reuse of the reclaimed material in the new courses of pavement placed as part of the motorway renewal project. The main objective of this research was to determine the properties of the tested concrete, including compressive strength, water absorption and freeze-thaw resistance after 150 cycles of alternate freezing and thawing. The resistance of the concrete to the action of de-icing products was also checked. The article also presents the results of petrographic analysis of the aggregates. Additionally, concrete sampled from the pavement was evaluated for freeze-thaw resistance in relation to the determined porosity characteristics. The tested concrete, which was subjected to over 80 years of traffic loading on the A6 motorway, was found to meet the highest requirements as currently applied for the extra heavy-duty pavements. With a compressive strength value in excess of 50 MPa, the tested concrete can be rated at least CC40, according to EN 13877-2:2013-08. The samples were found to satisfy the freeze-thaw resistance requirements of an F150 rating. The air void analysis showed that the analyzed concrete contained 1.6% of micropores, i.e., air voids smaller than 300 μm (A300). The spacing factor, in turn, was below 0.200 mm (L = 0.185 mm). The example of the A6 motorway renewal project served to demonstrate that reclaimed concrete aggregate, obtained by crushing the entire pavement, can be used for production of the new pavement courses.

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Study of the possibility of using modiﬁed ﬁne fraction obtained from recycled concrete rubble as cement additive

Cited by 2 publications

References 0 publications

Utilization of ground waste glass cullet in the industrial production of precast concrete elements

Utilization of ground waste glass cullet in the industrial production of precast concrete elements

Recycling of a Concrete Pavement after over 80 Years in Service

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