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Pietro Lura - One of the best experts on this subject based on the ideXlab platform.
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Internal Curing with superabsorbent polymers of different chemical structures
Cement and Concrete Research, 2019Co-Authors: Peihua Zhong, Mateusz Wyrzykowski, Nikolajs Toropovs, Jiaping Liu, Pietro LuraAbstract:Abstract This study investigates the absorption behavior of superabsorbent polymer (SAP) with different chemical structures and their effect on cement hydration, early-age autogenous shrinkage and mechanical properties of cement paste. SAP with high density of anionic functional groups absorbed the cement pore solution quickly, and then released it because the anionic groups on the network of SAP complexed with multivalent cations in the pore solution (e.g., Ca2+). Much less release was measured for SAP with low density of anionic groups. Furthermore, SAP with either both anionic and cationic groups or with only non-ionic groups did not release the liquid. Despite their different behavior in solutions, all SAP were able to counteract autogenous shrinkage. SAP with either both ionic groups or high density of anionic groups showed excellent Internal Curing effect. The Internal Curing had no negative effect on the compressive strength of the paste when the total cement-to-water ratio was considered.
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Internal Curing by superabsorbent polymers in ultra high performance concrete
Cement and Concrete Research, 2015Co-Authors: Pietro Lura, Mateusz Wyrzykowski, Janis Justs, Diana BajareAbstract:Abstract To limit self-desiccation and autogenous shrinkage that may lead to early-age cracking of ultra-high performance concrete (UHPC), Internal Curing by means of superabsorbent polymers (SAP) may be employed. Cement pastes and UHPC with water-to-cement ratio below 0.25, with or without SAP, were studied. The absorption capacity of a solution-polymerized SAP was first determined on hardened cement pastes by SEM image analysis. It was observed that the SAP cavities become partially filled with portlandite during cement hydration. Isothermal calorimetry showed that water entrainment with SAP delays the main hydration peak, while after a couple of days it increases the degree of hydration in a manner similar to increasing the water-to-cement ratio. Internal Curing by SAP is effective in reducing the Internal relative humidity decrease and the autogenous shrinkage. Although the mechanical properties are affected by SAP addition, it is possible to reach compressive strengths of almost 150 MPa at 28 days.
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Internal Curing with lightweight aggregate produced from biomass derived waste
Cement and Concrete Research, 2014Co-Authors: Pietro Lura, Mateusz Wyrzykowski, Clarence Tang, Eberhard LehmannAbstract:Shrinkage of concrete may lead to cracking and ultimately to a reduction of the service life of concrete structures. Among known methods for shrinkage mitigation, Internal Curing with porous aggregates was successfully utilized in the last couple of decades for decreasing autogenous and drying shrinkage. In this paper, the Internal Curing performance of pre-saturated lightweight aggregates produced from biomass-derived waste (bio-LWA) was studied. In the first part of this paper, the microstructure of the bio-LWA is investigated, with special focus on their pore structure and on their water absorption and desorption behavior. The bio-LWA has large porosity and coarse pore structure, which allows them to release the entrained water at early age and counteract self-desiccation and autogenous shrinkage. In the second part, the efficiency of Internal Curing in mortars incorporating the bio-LWA is examined by neutron tomography, Internal relative humidity and autogenous deformation measurements.
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An investigation on the use of zeolite aggregates for Internal Curing of concrete
Construction and Building Materials, 2013Co-Authors: Sadegh Ghourchian, Pietro Lura, Mateusz Wyrzykowski, Mohammad Shekarchi, Babak AhmadiAbstract:Abstract Shrinkage of concrete may lead to cracking and ultimately to a reduction of the service life of concrete structures. Among known methods for shrinkage mitigation, Internal Curing with porous aggregates has been successfully utilized in the last couple of decades for mitigating autogenous, drying and plastic shrinkage. In this paper, performance of LECA (Lightweight Expanded Clay Aggregate) and natural zeolite aggregates from Iran to act as Internal Curing agents was studied. While LECA is well recognized as an excellent Internal Curing agent in the literature, according to a few studies also some kind of zeolite aggregates may be used as Internal Curing agents. However, no in depth investigations on the microstructure of zeolite aggregates and on their desorption properties are available. In the first part of this paper, the microstructure of LECA and natural zeolite aggregates (clinoptilolite) from Iran are investigated and compared, with special focus on their pore structure and on their water absorption and release behavior. In the second part, the efficiency of Internal Curing in mortars incorporating these porous aggregates is examined. The results show that opposite to LECA, the zeolite aggregates examined in this research are not efficient as Internal Curing agents. While LECA showed high absorption and was able to release the water at high relative humidity, zeolite aggregates absorbed most of the water in nm-sized pores and retained the water down to low relative humidity levels. The performance of porous aggregates to act as Internal Curing agents is directly related to their Internal microstructure and resulting desorption properties, with zeolite aggregates performing poorly for mitigating early-age shrinkage.
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modeling of water migration during Internal Curing with superabsorbent polymers
Journal of Materials in Civil Engineering, 2012Co-Authors: Mateusz Wyrzykowski, Pietro Lura, Francesco Pesavento, Dariusz GawinAbstract:The mobility of water in hardening cement paste is an important aspect in view of the effectiveness of Internal Curing. A mechanistic-type numerical model of cementitious materials is applied for the analysis of water migration kinetics from Internal Curing agents [superabsorbent polymers (SAP)] into hydrating cement pastes with a low water-to-cement ratio. It is shown that the release of Curing water at early age (i.e., during approximately the first day of hydration) allows for a uniform and practically instantaneous distribution of water within the whole volume of cured paste, even if the distances for water migration are as high as 2–3 mm. The evolution of permeability, as a result of the hydration process, is shown to have a major impact on the mobility of water in the cement paste. The depercolation of capillary porosity may substantially inhibit the water transport. The analysis shows that a part of the water first received by the paste in the proximity of the SAP can be later redistributed to a large volume of hardening paste, even after the permeability has become very low.
Mateusz Wyrzykowski - One of the best experts on this subject based on the ideXlab platform.
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Internal Curing with superabsorbent polymers of different chemical structures
Cement and Concrete Research, 2019Co-Authors: Peihua Zhong, Mateusz Wyrzykowski, Nikolajs Toropovs, Jiaping Liu, Pietro LuraAbstract:Abstract This study investigates the absorption behavior of superabsorbent polymer (SAP) with different chemical structures and their effect on cement hydration, early-age autogenous shrinkage and mechanical properties of cement paste. SAP with high density of anionic functional groups absorbed the cement pore solution quickly, and then released it because the anionic groups on the network of SAP complexed with multivalent cations in the pore solution (e.g., Ca2+). Much less release was measured for SAP with low density of anionic groups. Furthermore, SAP with either both anionic and cationic groups or with only non-ionic groups did not release the liquid. Despite their different behavior in solutions, all SAP were able to counteract autogenous shrinkage. SAP with either both ionic groups or high density of anionic groups showed excellent Internal Curing effect. The Internal Curing had no negative effect on the compressive strength of the paste when the total cement-to-water ratio was considered.
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Internal Curing by superabsorbent polymers in ultra high performance concrete
Cement and Concrete Research, 2015Co-Authors: Pietro Lura, Mateusz Wyrzykowski, Janis Justs, Diana BajareAbstract:Abstract To limit self-desiccation and autogenous shrinkage that may lead to early-age cracking of ultra-high performance concrete (UHPC), Internal Curing by means of superabsorbent polymers (SAP) may be employed. Cement pastes and UHPC with water-to-cement ratio below 0.25, with or without SAP, were studied. The absorption capacity of a solution-polymerized SAP was first determined on hardened cement pastes by SEM image analysis. It was observed that the SAP cavities become partially filled with portlandite during cement hydration. Isothermal calorimetry showed that water entrainment with SAP delays the main hydration peak, while after a couple of days it increases the degree of hydration in a manner similar to increasing the water-to-cement ratio. Internal Curing by SAP is effective in reducing the Internal relative humidity decrease and the autogenous shrinkage. Although the mechanical properties are affected by SAP addition, it is possible to reach compressive strengths of almost 150 MPa at 28 days.
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Internal Curing with lightweight aggregate produced from biomass derived waste
Cement and Concrete Research, 2014Co-Authors: Pietro Lura, Mateusz Wyrzykowski, Clarence Tang, Eberhard LehmannAbstract:Shrinkage of concrete may lead to cracking and ultimately to a reduction of the service life of concrete structures. Among known methods for shrinkage mitigation, Internal Curing with porous aggregates was successfully utilized in the last couple of decades for decreasing autogenous and drying shrinkage. In this paper, the Internal Curing performance of pre-saturated lightweight aggregates produced from biomass-derived waste (bio-LWA) was studied. In the first part of this paper, the microstructure of the bio-LWA is investigated, with special focus on their pore structure and on their water absorption and desorption behavior. The bio-LWA has large porosity and coarse pore structure, which allows them to release the entrained water at early age and counteract self-desiccation and autogenous shrinkage. In the second part, the efficiency of Internal Curing in mortars incorporating the bio-LWA is examined by neutron tomography, Internal relative humidity and autogenous deformation measurements.
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An investigation on the use of zeolite aggregates for Internal Curing of concrete
Construction and Building Materials, 2013Co-Authors: Sadegh Ghourchian, Pietro Lura, Mateusz Wyrzykowski, Mohammad Shekarchi, Babak AhmadiAbstract:Abstract Shrinkage of concrete may lead to cracking and ultimately to a reduction of the service life of concrete structures. Among known methods for shrinkage mitigation, Internal Curing with porous aggregates has been successfully utilized in the last couple of decades for mitigating autogenous, drying and plastic shrinkage. In this paper, performance of LECA (Lightweight Expanded Clay Aggregate) and natural zeolite aggregates from Iran to act as Internal Curing agents was studied. While LECA is well recognized as an excellent Internal Curing agent in the literature, according to a few studies also some kind of zeolite aggregates may be used as Internal Curing agents. However, no in depth investigations on the microstructure of zeolite aggregates and on their desorption properties are available. In the first part of this paper, the microstructure of LECA and natural zeolite aggregates (clinoptilolite) from Iran are investigated and compared, with special focus on their pore structure and on their water absorption and release behavior. In the second part, the efficiency of Internal Curing in mortars incorporating these porous aggregates is examined. The results show that opposite to LECA, the zeolite aggregates examined in this research are not efficient as Internal Curing agents. While LECA showed high absorption and was able to release the water at high relative humidity, zeolite aggregates absorbed most of the water in nm-sized pores and retained the water down to low relative humidity levels. The performance of porous aggregates to act as Internal Curing agents is directly related to their Internal microstructure and resulting desorption properties, with zeolite aggregates performing poorly for mitigating early-age shrinkage.
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modeling of water migration during Internal Curing with superabsorbent polymers
Journal of Materials in Civil Engineering, 2012Co-Authors: Mateusz Wyrzykowski, Pietro Lura, Francesco Pesavento, Dariusz GawinAbstract:The mobility of water in hardening cement paste is an important aspect in view of the effectiveness of Internal Curing. A mechanistic-type numerical model of cementitious materials is applied for the analysis of water migration kinetics from Internal Curing agents [superabsorbent polymers (SAP)] into hydrating cement pastes with a low water-to-cement ratio. It is shown that the release of Curing water at early age (i.e., during approximately the first day of hydration) allows for a uniform and practically instantaneous distribution of water within the whole volume of cured paste, even if the distances for water migration are as high as 2–3 mm. The evolution of permeability, as a result of the hydration process, is shown to have a major impact on the mobility of water in the cement paste. The depercolation of capillary porosity may substantially inhibit the water transport. The analysis shows that a part of the water first received by the paste in the proximity of the SAP can be later redistributed to a large volume of hardening paste, even after the permeability has become very low.
Jason Weiss - One of the best experts on this subject based on the ideXlab platform.
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design methodology for partial volumes of Internal Curing water based on the reduction of autogenous shrinkage
Journal of Materials in Civil Engineering, 2018Co-Authors: Luca Montanari, Armen N Amirkhanian, Prannoy Suraneni, Jason WeissAbstract:AbstractHistorically, the use of Internal Curing began with a low water-to-cement ratio (w/c) and high-strength concrete. More recently, the benefits of reduced autogenous shrinkage and improved hy...
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Internal Curing for Concrete Pavements
2016Co-Authors: Jason WeissAbstract:This Tech Brief provides information on Internal Curing for concrete pavements by describing the primary concepts behind Internal Curing as well as describing aspects of practical applications, mixture design, construction, and quality control.
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The Influence of Lightweight Aggregate on Internal Curing and Its Impact on Autogenous Shrinkage of High-Performance Concrete
2014Co-Authors: Neil J Hartman, Timothy Barrett, Jason WeissAbstract:In bridge deck construction high performance concrete is often desirable, however in practice it is generally susceptible to early-age shrinkage cracking resulting in an overall reduction in service life. This research seeks to assess the potential for reducing early-age shrinkage in new bridge deck construction through the use of Internal Curing, a process in which Internal reservoirs supply water to the hydrating cement paste during the early stages of cement hydration. In North America, Internal Curing is typically achieved by replacing a portion of the normal fine aggregate with an expanded fine lightweight aggregate (LWA). For this study, the free and restrained autogenous shrinkage behavior was quantified for two field mixtures: a high performance concrete (HPC) and an Internally cured high performance concrete (ICHPC). The results indicate that Internal Curing successfully reduces the generation of autogenous shrinkage strain. When this shrinkage is restrained, it was shown that the ICHPC mixture was less susceptible to developing cracks in comparison to the HPC mixture. These findings suggest that Internal Curing can be used successfully in the field to reduce the potential for early-age shrinkage cracking, leading to production of bridge decks with longer service lives. Future research will implement these results in a service life estimation model to demonstrate the added value of Internal Curing bridge decks.
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fluid transport in high volume fly ash mixtures with and without Internal Curing
Cement & Concrete Composites, 2014Co-Authors: Igor De La Varga, Dale P. Bentz, Carmelo Di Bella, Javier Castro, Robert Spragg, Jason WeissAbstract:The transport of fluid and ions in concrete mixtures is central to many aspects of concrete deterioration. As a result, transport properties are frequently measured as an indication of the durability that a concrete mixture may be expected to have. This paper is the second in a series investigating the performance of high volume fly ash (HVFA) mixtures with low water-to-cementitious ratios (w/cm) that are Internally cured. While the first paper focused on strength and shrinkage, this paper presents the evaluation of the transport properties of these mixtures. Specifically, the paper presents results from: rapid chloride migration (RCM), rapid chloride penetration test (RCPT), apparent chloride diffusion coefficient, surface electrical resistivity, and water absorption. The test matrix consisted of mortar samples with two levels of class C fly ash replacement (40% and 60% by volume) with and without Internal Curing provided with pre-wetted lightweight fine aggregates (LWA). These mixtures are compared to plain ordinary portland cement (OPC) mortars. The results indicate that HVFA mixtures with and without Internal Curing provide benefits in terms of reduced transport coefficients compared to the OPC mixtures.
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Influence of Exposure Conditions on the Efficiency of Internal Curing in Concrete
Advances in Civil Engineering Materials, 2013Co-Authors: Michael Golias, Jason Weiss, Dale P. BentzAbstract:Internal Curing uses pre-wetted fine lightweight aggregate (LWA) to supply cementitious systems with water. This increases the hydration of cement and reduces the influence of self-desiccation resulting in concrete with increased compressive strength, reduced permeability, and reduced shrinkage potential. Whereas these mixtures have shown great potential, there has been considerable debate on how Internally cured samples should be conditioned during laboratory testing. This paper explores the influence of sample storage on the properties of mixtures prepared with and without Internal Curing. Samples were prepared and cured in different exposure conditions including environments in which: (1) moisture is supplied either via soaking or misting, (2) moisture is neutral, and (3) moisture loss is allowed. Experimental results show that when adequate external Curing water is supplied, only limited benefits are seen from Internal Curing. The benefits of Internal Curing are more evident in systems that do not receive additional external Curing water (sealed) and even more so when systems are exposed to external drying. Conditions where inadequate external Curing water is supplied may be more representative of what would be experienced in the field.
W. Jason Weiss - One of the best experts on this subject based on the ideXlab platform.
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Internal Curing for Concrete Bridge Decks: Integration of a Social Cost Analysis in Evaluation of Long-Term Benefit
Transportation Research Record, 2016Co-Authors: Yuntao Guo, Srinivas Peeta, W. Jason WeissAbstract:Internal Curing is a new approach to the proportioning of concrete mixtures in which a portion of the fine aggregate in concrete is replaced by prewetted lightweight fine aggregate. Internally cured concrete has the potential to extend the service life of bridge decks substantially because of reduced cracking and chloride ingress. Although Internally cured concrete has been used, its use is limited because of the slight increase in the initial cost and need for an understanding of batching operations and performance of quality control. Even though some cost–benefit studies have been performed, the potential life-cycle benefits of Internal Curing may be significantly underestimated because the social costs (network traffic disruptions) have not been integrated into previous studies. This study evaluated the total life-cycle benefits of bridge decks made of high-performance concrete with Internal Curing (HPC-IC) by a comparison of such bridge decks with bridge decks made of normal concrete (NC). Three bridg...
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Internal Curing as a New Tool for Infrastructural Renewal: Reducing Repair Congestion, Increasing Service Life, and Improving Sustainability
2014Co-Authors: Yuntao Guo, Timothy Barrett, Srinivas Peeta, Hong Zheng, Albert E Miller, W. Jason WeissAbstract:Internal Curing has recently been developed as a new concrete technology that has the potential to dramatically extend the service life of concrete infrastructure elements like bridge decks. Internal Curing uses prewetted lightweight aggregate (LWA) in low water to cement ratio, high performance concrete (HPC) to provide Curing water at the opportune time to minimize restrained shrinkage cracking and increase hydration of the cement resulting in reduced chloride ingress and corrosion. Internal Curing may be able to extend the service life of a concrete deck. The benefits of Internally cured concrete bridge decks (either new or replacements) at a system level, in the context of traffic disruptions resulting from renewal/repair needs and varying traffic flow congestion levels across different timescales, is a relatively unexplored concept. This research seeks to understand the potential benefits of Internally cured concrete mixtures compared to conventional mixture in a transportation system, thereby filling a key gap in the current Internal Curing literature. Findings from this research are as follows: Internal Curing generally results in a significant reduction in cracking as well as an improvement in the transport properties of concrete. These benefits are due in part to the reduced self-dessication, extended degree of hydration and the densification of the interfacial regions around the LWA. It was shown that for the service life model presented herein the Internally cured HPC concretes cast in the state of Indiana in 2013 achieve an estimated service life improvement of 3 to 4.5 times that of the conventional bridge deck concrete specified, while a field inspection of one of these bridges indicated no visible shrinkage cracking after six months of service. Recommendations are as follows: The research addressed in this project suggests that Internally cured concrete mixtures can represent an important and viable option for a transportation system to replace conventional concrete mixtures. Further, this research serves as a building block for exploring a new generation of analytical frameworks for application of Internally cured concrete mixture.
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Internal Curing of High Performance Concrete Using Lightweight Aggregates and Other Techniques
2014Co-Authors: Wesley A. Jones, Mitch W. House, W. Jason WeissAbstract:Internally cured concrete has been rapidly emerging over the last decade as an effective way to improve the performance of concrete. Internal Curing (IC) holds promise for producing concrete with an increased resistance to early-age cracking and enhanced durability (Bentz and Weiss, 2011). IC is a simple and effective way to cure concrete. Proper Internal Curing supplies water that is necessary to relieve stress buildup due to self-desiccation. Typically this is done using pre-wetted lightweight aggregates (LWAs), as this is the most commercially available application at the present time. IC has shown reduced autogenous and drying shrinkage cracking, improved fluid absorption resistance, improved compressive strength, and reduced ion diffusion. It is becoming increasingly clear that Internal Curing has great potential for the concrete industry to create a longer lasting, more sustainable product. This report specifically examines the freeze-thaw resistance of Internally cured concrete. It is shown that Internally cured concrete, using the recommended mixture proportions (i.e., pre-wetted fine LWAs to replace only the water lost due to chemical shrinkage) is freeze-thaw resistant. Internal Curing has shown, as outlined in this report, to be a simple and cost-effective way to create longer lasting, more durable concrete. The initial cost of a bridge deck concrete can increase in price anywhere from 3 to 10 $/yd3. However, this percentage when compared with the cost of a bridge is typically negligible, especially when considering an increased service life and reduced maintenance cost. Colorado Department of Transportation (CDOT) can benefit from this research by applying what has been presented in this study to create longer lasting, more durable bridge decks.
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Influence of Slag Aggregate Production on Its Potential for Use in Internal Curing
Transportation Research Record, 2014Co-Authors: Mitch W. House, Carmelo Di Bella, Hongfang Sun, George Zima, Laurent Barcelo, W. Jason WeissAbstract:Internal Curing is effective at reducing shrinkage and early-age cracking in cementitious systems with low water-to-cementitious materials ratios. In the United States, Internal Curing is typically accomplished using prewetted lightweight aggregate made by expanding slate, clay, or shale. This research focused on the use of porous slag aggregate, a byproduct of the iron and steel industry, for the Internal Curing of concrete. Five aggregates were evaluated for use in Internal Curing. The aggregates were produced from different manufacturing processes. Expanded, pelletized, and air-cooled slag aggregates were chosen for advanced testing. The research began by measuring the absorption and desorption properties of the aggregates. Laboratory testing of concrete mixtures containing select aggregates was performed to evaluate mechanical and durability properties. Full-scale testing was carried out with concrete produced at a ready-mix plant. A conventional department of transportation bridge deck mixture was co...
Janis Justs - One of the best experts on this subject based on the ideXlab platform.
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Internal Curing by superabsorbent polymers in ultra high performance concrete
Cement and Concrete Research, 2015Co-Authors: Pietro Lura, Mateusz Wyrzykowski, Janis Justs, Diana BajareAbstract:Abstract To limit self-desiccation and autogenous shrinkage that may lead to early-age cracking of ultra-high performance concrete (UHPC), Internal Curing by means of superabsorbent polymers (SAP) may be employed. Cement pastes and UHPC with water-to-cement ratio below 0.25, with or without SAP, were studied. The absorption capacity of a solution-polymerized SAP was first determined on hardened cement pastes by SEM image analysis. It was observed that the SAP cavities become partially filled with portlandite during cement hydration. Isothermal calorimetry showed that water entrainment with SAP delays the main hydration peak, while after a couple of days it increases the degree of hydration in a manner similar to increasing the water-to-cement ratio. Internal Curing by SAP is effective in reducing the Internal relative humidity decrease and the autogenous shrinkage. Although the mechanical properties are affected by SAP addition, it is possible to reach compressive strengths of almost 150 MPa at 28 days.