Effect of Superabsorbent Polymer on the Properties of Concrete

Investigating the Impact of Superabsorbent Polymer Sizes on Absorption and Cement Paste Rheology

This study aims to understand the water retention capabilities of Superabsorbent Polymers (SAPs) in different alkaline environments for internal curing and to assess their impact on the rheological properties of cement paste. Therefore, the focus of this paper is on the absorption capacities of two different sizes of polyacrylic-based Superabsorbent Polymers : SAP A, with an average size of 28 µm, and SAP B, with an average size of 80 µm, in various solutions, such as pH 7, pH 11, pH 13, and cement filtrate solution (pH 13.73). Additionally, the study investigates the rheological properties of SAP-modified cement pastes, considering three different water-to-cement (w/c) ratios (0.4, 0.5, and 0.6) and four different dosages of SAPs (0.2%, 0.3%, 0.4%, and 0.5% by weight of cement). The results showed that the absorption capacity of SAP A was higher in all solutions compared to SAP B. However, both SAPs exhibited lower absorption capacity and early desorption in the cement filtrate solution. In contrast to the absorption results in pH 13 and cement filtrate solutions, the rheological properties, including plastic viscosity and yield stress, of the cement paste with a w/c ratio of 0.4 and 0.5, as well as both dry and wet (presoaked) SAPs, were higher than those of the cement paste without SAP, indicating continuous absorption by SAP. The viscosity and yield stress increased over time with increasing SAP dosage. However, in the mixes with a w/c ratio of 0.6, the values of plastic viscosity and yield stress were initially lower for the mixes with dry SAPs compared to the reference mix. Additionally, cement pastes containing wet SAP showed higher viscosity and yield stress compared to the pastes containing dry SAP.

Synergistic Effects of SAP, Limestone Powder and White Cement on the Aesthetic and Mechanical Properties of Fair-Faced Concrete

In this investigation, a comprehensive assessment was conducted on the cooperative effects of Super Absorbent Polymers (SAP), limestone powder, and white cement within the realm of fair-faced concrete. We discerned that while white cement augments the color vibrancy of the concrete, its accelerated hydration rate potentially induced early-stage cracks and compromised performance. To mitigate these challenges, SAP was incorporated to regulate early hydration, and limestone powder was introduced as a fortifying agent to bolster the mechanical robustness of the concrete. Our findings highlighted not only the capability of SAP to enhance concrete workability and longevity but also the pivotal role of limestone powder in amplifying its mechanical attributes. Microscopic evaluations, undertaken via Scanning Electron Microscopy (SEM), unveiled the potential of both SAP and limestone powder in refining the microstructure of the concrete, thereby elevating its performance metrics. Synthesizing the research outcomes, we pinpointed an optimal amalgamation of SAP, limestone powder, and white cement in fair-faced concrete, offering a valuable reference for prospective architectural applications.

Mechanical Performance Improvement of Super Absorbent Polymer-Modified Concrete

In this study, a method has been developed to reduce the negative effects of superabsorbent polymers on concrete mechanical properties. The method involves concrete mixing and curing, with the concrete mixture being designed using a decision tree algorithm. Instead of the standard water curing approach, air curing conditions were used during the curing process. In addition, heat treatment was applied to reduce any possible negative effects of the polymers on the concrete's mechanical properties and to enhance their performance. The details of all these stages are presented in this method. Various experimental studies were conducted to demonstrate the validity of this method, which proved to be effective in reducing the negative effects of superabsorbent polymers on concrete mechanical properties. •The method can be used to eliminate the negative effects of superabsorbent polymers.•The proposed method yielded promising results, demonstrating that the expected level of compressive strength, modulus of elasticity and toughness in concrete can be achieved in 5-10 days instead of 28 days•The widespread use of superabsorbent polymers in the concrete industry and reinforced concrete systems can be attributed to their many benefits.

Research on Performance Deterioration of Internally Cured Pavement Concrete under the Coupling Effect of Salt Freeze-Thaw

This paper aims at solving the material durability problem caused by spraying deicing salt on pavement concrete in the northern winter. Super absorbent polymer (SAP) was adopted as an internal curing agent to enhance the durability of pavement concrete. Curing parameters including particle size and dosage of SAP and curing condition were optimized based on mortar tests by means of the grey target decision method. The deterioration rule of durability and mechanical properties of pavement concrete internally cured by different SAP dosages after salt freeze-thaw cycles were explored through rapid freeze-thaw test. Combined with the characteristics of pore structure, hydration and microstructure, the influence mechanism of SAP on the salt freeze-thaw resistance of pavement concrete was revealed. The experimental results showed that: (i) The reduction in mass loss rate and relative dynamic modulus was significantly improved by SAP internal curing with moderate dosage; (ii) The more freeze-thaw cycles the specimen underwent, the greater the increase in strength; (iii) After 75 cycles, the chloride ion erosion depth could be decreased by approximately 23.18%. Moreover, the addition of SAP could refine the pore size, inhibit the generation of shrinkage microcracks, and promote the degree of cement hydration in the late stage, which improved the internal density of the cement concrete structure. Therefore, the deterioration of pavement under the coupling effect of salt freeze-thaw was reduced.

Use of Cement Mortar Incorporating Superabsorbent Polymer as a Passive Fire-Protective Layer

Concrete structures, when exposed to fire or high temperatures for a certain time, could suffer partial damage or complete structural failure. Passive fire-protective coating materials are an alternative way to prevent or delay damage to concrete structures resulting from fire. Superabsorbent polymer (SP) is a synthetic material known for its ability to absorb and retain a large volume of water within itself. With this unique property, the SP exhibits great potential for use as a passive fire protection material. Although several studies have been carried out to investigate the effect of SP as a surface coating material for fire protection, very few have been investigated on the potential use of SP mixed with mortar as a passive fire-protective layer. The objective of this study is to introduce the use of SP in plastering mortar as a fire-protective layer for concrete subjected to temperatures up to 800 °C. This study is divided into two parts: (1) investigating the properties of cement mortar mixed with SP at 0.5% (CONC/SP-0.5) and 1.0% (CONC/SP-1.0) by weight of cement, and (2) investigating the potential use of SP mortar as a plastering layer for concrete subject to high temperatures. The experimental results showed that the density and compressive strength of SP mortar decreases with increasing SP dosages. From the heat exposure results, SP mortar exhibited lower strength loss due to the ability to mitigate moisture through its interconnected pore system. As for the use of SP mortar as a plastering layer, the results demonstrated the concrete specimen plastered with SP mortar had a lower temperature at the interface and core than that plastered with plain mortar. This led to a reduced strength loss of 20.5% for CONC/SP-0.5 and 17.2% for CONC/SP-1.0.

Effect of Superabsorbent Polymers on the Self-Healing Properties of Pre-Damaged Concrete

Cracks in concrete structures reduce bearing capacity, durability, and safety. This paper reveals the effect of superabsorbent polymers (SAP) on the self-healing property of pre-damaged concrete based on mechanical properties tests, mercury intrusion porosimetry, scanning electron microscopy, and energy dispersive spectrometer. The experimental results show that SAP reduces the mechanical properties of the SAP-modified concrete under the same W/C ratio, but a small amount of SAP can improve the later strength under the 0.35 W/C ratio. The addition of SAP increased the volume of small capillary pores (<20 μm) and large capillary pores (>100 μm) and significantly reduced the former with an increase in age. The SEM-EDS analysis indicates that the water released by SAP promotes the formation of C-S-H gel. AFt in the cracks is the main reason for self-healing, and the addition of CO2 to produce calcium carbonate is another one. Furthermore, this study finds that SAP-modified concrete has the best self-healing effect and the densest structure when the W/C ratio is 0.35 and the SAP content is 0.25%. The self-healing performance makes the SAP-modified concrete have broad application prospects.

Influence of Fineness of Wheat Straw Ash on Autogenous Shrinkage and Mechanical Properties of Green Concrete

This study investigates the effectiveness of an agricultural by-product wheat straw ash (WSA) as an internal curing agent in reducing the autogenous shrinkage of high-performance concrete (HPC). After incineration under different controlled time–temperature conditions, grinding and sieving were performed to obtain two different grades of fine WSA (F-WSA) and superfine WSA (SF-WSA). Subsequently, material characterization tests were carried out, followed by tests for mechanical properties and autogenous shrinkage potential of concrete incorporating 10% and 20% F-WSA and SF-WSA as a partial replacement of cement. The results demonstrated slightly higher compressive and tensile strength of concrete containing SF-WSA compared to control, whereas concrete with F-WSA demonstrated comparable strength results to that of the control concrete. Moreover, a significant reduction in 7 days’ autogenous shrinkage was observed in concrete containing 10% and 20% F-WSA by 42% and 25% compared to that of control concrete, respectively. This reduction in autogenous shrinkage increased further to 57% and 40% for concrete with 10% and 20% SF-WSA, respectively. The results of microstructural investigations on paste samples such as FTIR, TGA, and N2 adsorption analyses revealed a more refined and compact microstructure of paste samples with increasing fineness of WSA due to the formation of a more densified C-S-H phase. The improvement of the microstructure is attributable to the improved pozzolanic properties of SF-WSA compared with F-WSA.

Effects of Secondary Porosity on Microstructure and Mechanical Properties of SAP-Containing Lime-Based Plasters

Despite the many benefits associated with the utilization of superabsorbent polymers (SAPs), several drawbacks have been reported. In particular, the effect of SAPs on microstructure, together with its consequences for mechanical properties, is not fully understood yet for some composite materials. This study analyzes the role of SAPs in the formation of the microstructure of lime composites, taking into account their chemical composition. The obtained experimental results show that the particle size and cross-linking density of used SAPs are crucial parameters affecting both the microstructure and mechanical performance of the analyzed composites. Coarser SAPs with low cross-linking density in the dosage of 0.5 and 1 wt.% are found as the most suitable solution, leading even to a slight improvement of mechanical parameters. The secondary porosity formed by swelled hydrogels is identified as a very significant factor since hydrogel-filled voids do not contribute to the strength parameters. The formation of the affected zone around SAP cores depends on the chemical composition of SAPs considerably as the higher cross-linking density influences the desorption rate. Based on achieved results, utilization of SAPs in building materials should be studied at a more detailed level with particular importance on the definition of SAP-related voids and affected zone around SAP particles.

The Effect of Superabsorbent Polymer on the Resilient and Plastic Strain Behavior of Cemented Soil under Traffic Load

In road construction, a large number of excavated soils need to be treated with stabilizers. The addition of superabsorbent polymer (SAP) can improve the road performance of these stabilized soils. In order to predict roadbed deformation, dynamic triaxial tests were carried out on cemented soil containing SAP to investigate its resilient and plastic strain behavior. The effects of SAP content, cyclic stress ratio, and loading frequency on cement-stabilized soils with SAP were analyzed combined with the number of cycles. This study demonstrates how these influencing factors effect the resilient strain, dynamic elastic modulus, and accumulated plastic strain, which are crucial to better understanding the strain behavior of cement-stabilized soil with SAP. The results show that SAP can significantly improve the brittle failure characteristics and dynamic strength of cement-stabilized soil. Soil with higher SAP content possesses smaller accumulated plastic strain; with the increase in the cyclic stress ratio, the dynamic elastic modulus decreases significantly, whereas the accumulated plastic strain has the opposite trend. In addition, the lower frequency produces larger cumulative axial strain.

A Review on the Use of Self-Curing Agents and Its Mechanism in High-Performance Cementitious Materials

Self-cured concrete is a type of cement-based material that has the unique ability to mitigate the loss rate of water and increase the capacity of concrete to retain water compared to conventional concrete. The technique allows a water-filled internal curing agent to be added to the concrete mixture and then slowly releases water during the hydration process. Many researchers have studied the composition of self-curing concrete using different materials such as artificial lightweight aggregate (LWA), porous superfine powders, superabsorbent polymers (SAP), polyethylene glycol (PEG), natural fibers, and artificial normal-weight aggregate (ANWA) as curing agents. Likewise, physical, mechanical, and microstructure properties, including the mechanisms of curing agents toward self-curing cement-based, were discussed. It was suggested that adopting self-curing agents in concrete has a beneficial effect on hydration, improving the mechanical properties, durability, cracking susceptibility behavior, and mitigating autogenous and drying shrinkage. The interfacial transition zone (ITZ) between the curing agent and the cement paste matrix also improved, and the permeability is reduced.

The Effect of Superabsorbent Polymer and Nano-Silica on the Properties of Blended Cement

Incorporating superabsorbent polymer (SAP), which has the abilities of absorption and desorption in cement mortar, can achieve the effect of internal curing. It is expected that the incorporation of nano-silica will improve the workability and strength in cement mortar/concrete. Hence, this study aims to examine the effect of SAP and nano-silica on the properties of blended cement paste. The experimental investigations via several tests such as consistency, setting time, compressive strength, UPV, and acid test were performed. Based on energy-dispersive X-ray analysis (EDX) test and scanning electron microscopy (SEM) test results, the morphology of hydration products and mineral compositions of cement paste were further analysed, and the mechanism of SAP with 0.2% and 0.3% and NS with lower percentages ranging from 0.5% to 2% on the performance of cement paste was studied. The results exhibited that incorporating SAP in various percentages from 0.5% to 2% prolonged the initial setting time, reduced the fluidity, and increased the water content and formation of pores. In addition, various percentages ranging from 0.5% to 2% of NS were added; thereby, an increase in the hydration process and refining the microstructure was found. The microscopic test results showed that the blended cement paste can effectively improve the denser microstructure and refine the pore structure.

Microstructure Formation of Cement Mortars Modified by Superabsorbent Polymers

The utilization of superabsorbent polymers (SAPs) in cement-based materials has been found to be a promising means of mitigating the autogenous propagation of shrinkage and cracks. On the other hand, the undesired effects of SAPs' application on functional properties, including mechanical strength, microstructure formation, and the evolution of hydration heat are not properly understood, given the variety in SAPs' characteristics. To contribute to the present state-of-the-art, cement mortars, modified with two grades of SAPs by dosages of 0.3%, 0.6%, and 0.9%, were designed and studied with emphasis on the relationship between the materials' porosities and mechanical strengths. The obtained results are interpreted by scanning electron microscopy analysis and hydration heat evolution to elucidate the major changes and their driving factors. Besides the benefits associated with the mitigation of autogenous shrinkage, the achieved results point to an adverse effect of supplementation with SAP on mechanical strength at an early age, and an even more pronounced increase at a later age. The employed scanning electron microscopy images, together with mercury-intrusion porosimetry data, depict distortion in the material porosity as a result of the filling of formed voids and the closing of open ends by swelled hydrogels. Only the minor benefit of a greater cross-linking density was obtained by the formation of dense structures and the gains in mechanical strength therefrom.

Effect of Superabsorbent Polymer on the Mechanical Performance and Microstructure of Concrete

The internally cured material known as superabsorbent polymer (SAP) is an important innovation in concrete engineering technology. This paper investigates the effect of adding a polymer with superabsorbent capabilities on the physical and mechanical performance of concrete. The microstructure of the new hybrid concrete was also studied, and the influence of the polymer particle size and volume on the mechanical durability was evaluated. The mechanical properties of the new hybrid concrete, such as compressive strength, flexural strength, elastic modulus, and splitting tensile strength, were measured through laboratory experiments. The microstructure characteristics of the concrete were also investigated by scanning electron microscopy (SEM). The results show that shrinkage was reduced, while the volume stability of the concrete improved. Moreover, we found that cracking was reduced, while issues such as chloride penetration and freeze-thaw resistance were also improved. In addition, the SAP could effectively improve the microstructure of the concrete and refine the pore structure, as seen in the microscopic test. This paper helps to promote the development of internally cured material and improve technology for the prevention of concrete construction cracks.

Effect of Absorptivity of Superabsorbent Polymers on Design of Cement Mortars

The functional properties of composites modified by superabsorbent polymers (SAPs) strongly depend on the swelling capacity of applied SAPs. In this sense, three types of commercially available SAPs namely Cablock CT, Hydropam, and Creasorb SIS with different chemical composition and particle size distribution were studied in this manuscript to reveal the differences in absorptivity as can be viewed as pretests for their utilization in concrete composites. In addition, absorptivity in distilled water, tap water, and 0.1 M NaCl solution are examined for determining the SAPs response for the change of the solution pH. To overcome problems with the teabag method inaccuracy, the new method is introduced. Besides to quantitative evaluation of the SAPs absorptivity, the correlation for the absorption and desorption period as the function of SAPs residence time within the examined solution is proposed. To access the effect of selected SAPs on functional properties, optimization based on the flow table test is employed and mechanical parameters are determined after 7, 14, 28, and 90 days of curing. Obtained results refer to substantial differences between particular SAPs and contribute to the understanding of the effect of SAP on the functional properties of cement-based materials.

Effect of Internal Curing by Super Absorbent Polymer on the Autogenous Shrinkage of Alkali-Activated Slag Mortars

Alkali activated slag (AAS) mortar is becoming an increasingly popular green building material because of its excellent engineering properties and low CO₂ emissions, promising to replace ordinary Portland cement (OPC) mortar. However, AAS’s high shrinkage and short setting time are the important reasons to limit its wide application in engineering. This paper was conducted to investigate the effect of internal curing(IC) by super absorbent polymer (SAP) on the autogenous shrinkage of AAS mortars. For this, an experimental study was carried out to evaluate the effect of SAP dosage on the setting time, autogenous shrinkage, compressive strength, microstructure, and pore structure. The SAP were incorporated at different dosage of 0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 percent by weight of slag. The workability, physical (porosity), mechanical, and shrinkage properties of the mortars were evaluated, and a complementary study on microstructure was made. The results indicated that the setting time increased with an increase of SAP dosage due to the additional activator released by SAP. Autogenous shrinkage decreased with an increase of SAP dosage, and was mitigated completely when the dosage of SAP ≥ 0.2% wt of slag. Although IC by means of SAP reduced the compressive strength, this reduction (23% at 56 days for 0.2% SAP) was acceptable given the important role that it played on mitigating autogenous shrinkage. In the research, the 0.2% SAP dosage was the optimal content. The results can provide data and basis for practical application of AAS mortar.

Influence of Environmental Factors on the Swelling Capacities of Superabsorbent Polymers Used in Concrete

Superabsorbent polymers (SAP) are of major interest as materials to control the cement hydration process. The swelling behavior of the SAPs significantly influences the performance of the resulting concrete by slowly releasing polymer-bound water in order to maintain a consistent w/c value. A round-robin test conducted by the RILEM Technical Committee 260-RSC showed that the same batch of polymer can lead to large deviations in concrete performance and this was assumed to originate in different storage conditions of the SAP. In this contribution the change in the performance of two SAPs, a crosslinked poly(acrylate) and a crosslinked poly(acrylate-co-acrylamide), was assessed after ageing in standard climate, at 50 °C, and under UV irradiation. During storage in standard climate or 50 °C, ageing led to dehydration of the SAP, and this subsequently led to a higher water uptake during swelling. By contrast, UV irradiation reduced the water uptake, most likely as a result of photo-crosslinking. Dynamic water vapor sorption experiments indicated a strong dependence of the water uptake on both the ambient humidity and the temperature. As a result, cement mixtures containing SAP must be calculated on the dry mass of the SAP rather than the actual weight on site. A standard procedure of how to pack and handle SAP to be used in concrete is also provided.

Micro-computed tomography evaluation of root canal filling quality with apical negative pressure

OBJECTIVES

The objective of the present study was to compare, using micro-computed tomography (micro-CT), the location and volume percentage of voids in root canals that were obturated with a premixed tricalcium silicate sealer and a single gutta-percha master cone, in the presence or absence of apical negative pressure.

METHODS

Twenty extracted human mandibular premolars were cleaned and shaped. The teeth were assigned to 2 groups (n = 10) according to the filling technique: apical negative pressure sealer application combined with the single-cone technique (NPS) or syringe-assisted sealer application combined with the single-cone technique (SS). Each specimen was scanned using micro-CT at 10 μm resolution. The percentages of voids were calculated from segmental regions of interest. Data were analysed using nonparametric statistical methods, with statistical significance pre-set at α = 0.05.

RESULTS

Significant difference was identified (p < 0.05) in the overall percentage of voids between the NPS group (0.33 %; interquartile range 0.25 %) and the SS group (6.29 %; interquartile range 5.57 %). In the NPS group, the percentages of voids in the coronal-third or middle-third of the canal space were statistically lower than that in apical-third (p < 0.0167, Bonferroni adjustment), with no significant difference between the former two groups. In the SS group, no significant difference in the percentages of voids was identified among the coronal-third, middle-third and apical-third of the canal space.

CONCLUSIONS

Apical negative pressure sealer application combined with the single-cone technique produces fewer voids in root canal fillings than the conventional single-cone technique.

CLINICAL SIGNIFICANCE

The apical negative pressure sealer application technique combined with single-cone filling constitutes a novel root canal obturation technique that improves the quality of root canal filling by minimising the volume of voids within the three-dimensional canal space.

Autogenous Healing of Early-Age Cementitious Materials Incorporating Superabsorbent Polymers Exposed to Wet/Dry Cycles

This study experimentally investigated the autogenous healing performances of cementitious materials incorporating superabsorbent polymers (SAPs) after exposure to eight cycles of wet/dry conditions. In each cycle, cracked cement paste specimens with different SAP dosages were exposed to wet conditions for 1 h, during which capillary water absorption tests were conducted, and then exposed to dry conditions for 47 h. The test results reveal that the initial sorptivity values of the reference, 0.5% SAP, 1.0% SAP, and 1.5% SAP specimens after one cycle were decreased by 22.9%, 36.8%, 42.8%, and 46.3%, respectively, after eight cycles. X-ray micro-computed tomography analysis showed that the crack volume percentages filled with healing products were 1.1%, 1.6%, 2.2%, and 2.9% in the reference, 0.5% SAP, 1.0% SAP, and 1.5% SAP specimens, respectively. As the cycling was repeated, the reduction ratio of the initial sorptivity and the quantity of healing products were increased with increases in SAP dosage. Furthermore, more healing products were distributed near SAP voids than in other sections in the specimens. This study demonstrates that the incorporation of SAPs in cementitious materials can enhance the autogenous healing performances of materials exposed to cyclic wet/dry conditions.

The Role of Superabsorbent Polymer on Strength and Microstructure Development in Cemented Dredged Clay with High Water Content

This paper presents the role of superabsorbent polymer (SAP) on strength and microstructure development in cemented clays with notably high water content. A series of unconfined compressive strength (UCS), scanning electron microscope (SEM) and X-ray diffraction (XRD) tests were performed to identify strength behavior and microstructure. Results showed that SAP significantly influenced the mechanical behavior of cemented clays with notably high water content, characterized by an increase in the unconfined compressive strength and a decrease in the after-curing water content with SAP content. This revealed that the strength increase due to SAP was directly related to the water absorption by SAP. Meanwhile, XRD results showed that the hydration products were controlled by cement and lime content, regardless of SAP content. That meant there was no chemical reaction between SAP particles used in this study and cement or lime. The microstructure analysis by SEM revealed that SAP played an important role in the microstructure of cemented clays. With an increase in SAP content, the water absorbed by SAP increased significantly, leading to a decrease in the pore volume and a denser soil fabric. This behavior indicated that the primary role of SAP on strength increase was to absorb and fix water in cemented clays. Consequently, the clay⁻cement cluster distance decreased with an increase in solid mass (soil particles and swollen SAP particles) and a decrease in pore water. The corresponding tighter flocculated fabric due to SAP eventually led to the strength increase.

Swelling Behaviour of Superabsorbent Polymers for Soil Amendment under Different Loads

One of the most important among the numerous applications of superabsorbent polymers (SAPs), also known as hydrogels, is soil improvement and supporting plant vegetation in agriculture and environmental engineering. Currently, when water scarcity involves water stress, they are becoming still more commonly used for water retention in soil. As it turns out, one of the major factors influencing the superabsorbent polymers water retention capacity (WRC) is the load of soil. The study presents test results of absorbency under load (AUL) of SAPs. The object of the analysis was cross-linked copolymer of acrylamide and potassium acrylate, of a granulation of 0.50⁻3.15 mm. The authors analysed the water absorption capacity of the superabsorbent polymers under loads characteristic for 3 different densities of soil (1.3 g∙cm-3, 0.9 g∙cm-3, 0.5 g∙cm-3) and three different depths of application (10 cm, 20 cm, and 30 cm). Soil load and bulk densities were simulated by using weights. The experiments were conducted with a Mecmesin Multitest 2.5-xt apparatus. The obtained results demonstrate a very significant reduction in water absorption capacity by SAP under load. For a 30 cm deep layer of soil of bulk density of 1.3 g∙cm-3, after 1 h, this value amounted to 5.0 g∙g-1, and for the control sample without load, this value amounted to more than 200 g∙g-1. For the lowest load in the experiment, which was 0.49 kPa (10 cm deep layer of soil of a bulk density of 0.5 g∙cm-3), this value was 33.0 g∙g-1 after 60 min. Loads do not only limit the volume of the swelling superabsorbent polymer but they also prolong the swelling time. The soil load caused a decrease in the absorption capacity from 338.5 g∙g-1 to 19.3 g∙g-1, as well as a prolongation of the swelling time. The rate parameter (time required to reach 63% of maximum absorption capacity) increased from 63 min for the control sample to more than 300 min for the largest analysed load of 3.83 kPa. The implications of soil load on superabsorbent polymer swelling are crucial for its usage and thus for the soil system. This knowledge might be employed for the more effective usage of superabsorbent polymers in agriculture and environmental engineering, in which they are commonly used to retain water and to support plant growth.