Mixing protocols for plant‐scale production of concrete with superabsorbent polymers

Abstract

Superabsorbent polymers (SAPs) have been investigated for their potential for internal curing, promotion of self-sealing, and self-healing of concrete structures. There has been a lack of publications concerning large-scale testing of structures with SAPs, and bringing this SAP-modified concretes from laboratory environment to plant-scale production might demand adaptations in the mixing protocols. In this paper, a reference mixture and a SAP-containing mixture were produced at a concrete plant scale and the influence of adding the polymers at different moments was investigated. The addition of SAPs directly in the truck, after the mixing procedure, showed no significant impact on the compressive strength of the concrete, but an agglomeration of particles was found in the air void analysis. The specimens with SAPs added directly in the truck presented an inferior performance in terms of shrinkage reduction when compared to the specimens with SAPs added on the materials belt, with the dry materials.

Relationship between internal relative humidity and autogenous shrinkage of early‐age concrete containing prewetted lightweight aggregates

“…The R 2 values obtained from Equations ( 8)- (11) were in the range of 0.963-0.986, which indicated that the prediction results coincided with the test results. The absolute values of the slopes of the fitting curves increased with a larger quantity of IC water, which was possibly due to the diffusion rate of IRH or the rate of cement hydration.…”

“…7,8 Moisture loss is one of the most critical factors for concrete shrinkage 9 and shrinkage-related cracks. 10 The generation and development of cracks provide paths for corrosive media, 11,12 which weakens the load-carrying capacity 13 and durability of concrete. 14,15 Early age is commonly a crucial stage for concrete.…”

Environmental and economic sustainability of crack mitigation in reinforced concrete with SuperAbsorbent polymers (SAPs)

“…1, several cracks were already observed. In previous laboratory experiments it was furthermore shown that this concrete mixture had the potential to reduce water permeability through cracks of up to 250 µm in width, and increase the resistance to saltscaling under frost attack with a limited reduction in the compressive strength (Tenório Filho et al, 2021a)(Tenório Filho et al, 2020a)(Tenório Filho et al, 2020b)(Tenório Filho et al, 2019)(Tenório Filho et al, 2021b. Tenório Filho, 2021a) 3 Concrete walls repair Nowadays, several methods are available to restore the functionality of damaged concrete structures, with a broad variety of materials and technologies to be used according to the occurred damage.…”

Recent progress in superabsorbent polymers for concrete

“…Tenório Filho et al found that incorporating SAP into mixtures at the concrete production plant influences autogenous shrinkage, with reduced autogenous shrinkage observed when SAP was added to the materials belt with other dry components compared to when SAP was added directly to the truck after the (wet) mixing procedure. When SAP was added to the truck, it resulted in poor dispersion and subsequent agglomeration of SAP particles within the mixture that reduced internal curing performance [205]. In a follow-up study, Tenório Filho et al erected crack-free concrete walls in a largescale demonstrator in the dimensions of 14 m x 2.75 m x 0.80 m per each specimen.…”