Influence of superabsorbent polymers on hydration of cement pastes with low water-to-binder ratio: A calorimetry study

Internal curing with superabsorbent polymers (SAP) is a method for promoting hydration of cement and limiting self-desiccation, shrinkage and cracking in high-performance, and ultra high-performance concrete with low water-to-binder ratio. SAP are introduced in the dry state during mixing and form water-filled inclusions by absorbing pore solution. The absorbed solution is later released to the cement paste during hydration of the cement. In this paper, cement pastes with low water-to-binder ratios incorporating superplasticizer and different dosages of SAP and corresponding additional water were prepared. Reference cement pastes without SAP but with the same amount of water and superplasticizer were also mixed. Isothermal calorimetry was used to measure hydration heat flow. Water entrainment by means of SAP increased the degree of hydration at later hydration times in a manner similar to increasing the water-to-binder ratio. Addition of SAP also delayed the main calorimetric hydration peak compared to the reference pastes, however, in a less prominent manner than the increase in water-to-cement ratio

Application of super absorbent polymers (SAP) in concrete construction—update of RILEM state-of-the-art report

Superabsorbent polymers (SAP) are a new, promising class of chemical admixtures which offer new possibilities in respect of influencing the properties of cement-based materials in the fresh, hardening, and hardened states. Much research work has been done in the last two decades to set the stage for introducing this truly multipurpose agent into the practice of construction. In particular, three RILEM Technical Committees: 196-ICC, 225-SAP and 260-RSC contributed considerably to the related progress by coordinating and combining the efforts of international experts in the field. The major product of the RILEM TC 225-SAP work was the State-of-the-Art Report published in 2012. This comprehensive document covered all topics relevant to the application of SAP as a concrete admixture. Since then further important progress has been made in understanding the working mechanisms of SAP in concrete and the effects of SAP-addition on various concrete properties. The article at hand presents an update on the state-of-the-art and is the concluding document delivered by the RILEM TC 260-RSC

Testing superabsorbent polymer (SAP) sorption properties prior to implementation in concrete: results of a RILEM Round-Robin Test

This article presents the results of a round-robin test performed by 13 international research groups in the framework of the activities of the RILEM Technical Committee 260 RSC "Recommendations for use of superabsorbent polymers in concrete construction''. Two commercially available superabsorbent polymers (SAP) with different chemical compositions and gradings were tested in terms of their kinetics of absorption in different media; demineralized water, cement filtrate solution with a particular cement distributed to every participant and a local cement chosen by the participant. Two absorption test methods were considered; the tea-bag method and the filtration method. The absorption capacity was evaluated as a function of time. The results showed correspondence in behaviour of the SAPs among all participants, but also between the two test methods, even though high scatter was observed at early minutes of testing after immersion. The tea-bag method proved to be more practical in terms of time dependent study, whereby the filtration method showed less variation in the absorption capacity after 24 h. However, absorption followed by intrinsic, ionmediated desorption of a specific SAP sample in the course of time was not detected by the filtration method. This SAP-specific characteristic was only displayed by the tea-bag method. This demonstrates the practical applicability of both test methods, each one having their own strengths and weaknesses at distinct testing times

Application of super absorbent polymers (SAP) in concrete construction : update of RILEM state-of-the-art report

Superabsorbent polymers (SAP) are a new, promising class of chemical admixtures which offer new possibilities in respect of influencing the properties of cement-based materials in the fresh, hardening, and hardened states. Much research work has been done in the last two decades to set the stage for introducing this truly multipurpose agent into the practice of construction. In particular, three RILEM Technical Committees: 196-ICC, 225-SAP and 260-RSC contributed considerably to the related progress by coordinating and combining the efforts of international experts in the field. The major product of the RILEM TC 225-SAP work was the State-of-the-Art Report published in 2012. This comprehensive document covered all topics relevant to the application of SAP as a concrete admixture. Since then further important progress has been made in understanding the working mechanisms of SAP in concrete and the effects of SAP-addition on various concrete properties. The article at hand presents an update on the state-of-the-art and is the concluding document delivered by the RILEM TC 260-RSC.Projekt DEA

Verification of the presence of superabsorbent polymers (SAP) in fresh concrete : results of an interlaboratory study of RILEM TC 260-RSC

New methods are proposed for the verification of the presence of superabsorbent polymers (SAP) in freshly mixed concrete and estimation of SAP quantity. The methods are in general based on flushing concrete with excess water. They allow separating the light, water-sorbed hydrogel particles from the mineral components in the fresh concrete and making these particles available for further tests. Two types of tests are proposed: Test 1 serves for a visual verification of the presence of SAP (qualitative test), while Test 2 enables quantifying the mass of the collected SAP as a proxy of their concentration in concrete (quantitative test). Different procedures are proposed for these two test methods and their performance is evaluated. The testing procedures were scrutinized in an interlaboratory study carried out by 14 participants from 12 countries. All participating groups detected the presence of SAP in the mix using the qualitative procedures (Test 1). Based on this outcome, we suggest that this method should be applied in the field. In contrast, while most participants obtained reasonably reliable results with the quantification procedure of Test 2, some participants reported large errors. Therefore, the quantification method needs to be further refined, starting from the experience gained in this interlaboratory study.Open Access funding provided by Lib4RI.http://link.springer.com/journal/11527Civil EngineeringSDG-09: Industry, innovation and infrastructur

Seven Prophetesses According to the Babylonian Talmud (Meg. 14a-15a)

Prorocy przekazujący ludowi wolę Boga pełnili swoją nadprzyrodzoną misję i mieli realny wpływ na instytucje odpowiadające za funkcjonowanie państwa. Biblia Hebrajska mówi również explicite o powołaniu prorokiń. Tradycja ta została rozwinięta i szczegółowo omówiona w talmudycznym traktacie Megilla (14a-15a). Rabini tytuł ten przyznali siedmiu kobietom: Sara, Miriam, Debora, Anna, Abigail, Chulda i Estera. Niniejszy artykuł ma na celu zaprezentowanie oraz omówienie aspektów z ich życia oraz przesłania, które przełożyły się na nadanie im tytułu „prorokini”.Prophets announced the will of God to the people, fulfilled their supernatural mission and had a real influence on the institutions responsible for the functioning of the state. the hebrew bible also speaks explicitly about the calling of prophetesses. this tradition was developed and discussed in detail in the talmudic tractate Megilla (14a-15a). the rabbis gave this title to seven women: Sarah, Miriam, Deborah, Anna, Awigail, huldah and esther. this article aims to present and discuss aspects of their lives and the message that resulted in giving them the title of “prophetess”

Priesthood in the light of the Greek Testament of Levi (14–16)

The Greek Testament of Levi describes the origin of the priesthood from Levi. In the text, he gives advice to his sons and teaches how they are to serve in the temple. He encourages priests to acquire knowledge because thanks to wisdom they will have respect in the community. In the last instruction before his death he warns them against sins. Sin, according to Levi, will destroy the temple. In the Testament, Levi announces the “new priest” who will renew cult. The text about the “new priest” Christians identified with Jesus Christ, and the words of Levi were to be an instruction for the priests of the Church

The Meaning of the Term בית מדרשׁ in Pseudo-Jonathan’s Targum

Jednym z najważniejszych zadań rodziców w starożytnym Izraelu było przekazanie wiedzy dotyczącej Prawa Mojżeszowego. Zgodnie z tradycją chłopcy po zdobyciu podstawowej wiedzy w domu szli do szkoły, gdzie kontynuowali naukę. Tekst Biblii bardzo mało mówi o samym procesie kształcenia. Informacje te podaje datowany na VII wiek po Chr. Targum Pseudo-Jonatana. Celem artykułu jest zaprezentowanie oraz przeanalizowanie znaczenia terminu בית מדרשׁ w Targumie Pseudo-Jonatana. Zwrot ten nie pojawia się w Biblii Hebrajskiej. Autor targumu dodał go celowo w czternastu wersetach Tory. Analiza znaczenia tego terminu w konkretnych perykopach ma ukazać znaczenie szkoły oraz nadania jej starożytnego charakteru. Zaprezentowane treści prowadzą do wniosku, że po upadku świątyni w Jerozolimie, gdy przestrzeganie Prawa zaczęło stanowić najistotniejszy element w religii żydów, autor targumu Pseudo-Jonatana chciał wykazać początki בית מדרשׁ już w czasach Abrahama.One of the most important tasks of parents in ancient Israel was to impart knowledge of the Mosaic Law to their children. According to tradition, having gained basic knowledge at home, boys would attend school to continue their education of which the Bible offers little information. This information is provided by 7th century Targum Pseudo-Jonathan. The article analyzes the meaning of the term בית מדרשׁ in Pseudo-Jonathan’s Targum. This phrase does not occur in the Hebrew Bible. The author of the targum added it intentionally in fourteen verses of the Torah. The analysis of the meaning of this term in specific pericopes is to show the importance of school and give it an ancient character. The presented content leads to the conclusion that after the demolishon of the temple in Jerusalem, when the observance of the Law began to be the most important element in the religion of the Jews, the author of the Targum Pseudo-Jonathan wanted to show the origins of בית מדרשׁ in the times of Abraham

Reinterpretacja perykopy o synach Bożych i córkach ludzkich (Rdz 6,1-4) w Księdze Czuwających (1 Hen 6-7)

Artykuł prezentuje reinterpretację Rdz 6,1-4 w Księdze Henocha. Opisuje ona obszernie kontekst niemoralnego postępowania ludzkości, potraktowany bardzo syntetycznie w Rdz 6,1-4. Jednocześnie uzupełnia informacje dotyczące gigantów, które nie zostały opisane w Biblii. Zło, którego się dopuścili oraz fizyczna wielkość gigantów stanowią uzasadnienie podjęcia przez Boga decyzji o zesłaniu na świat potopu (Rdz 6,5-7). Niniejszy artykuł to analiza Rdz 6,1-4 biorąca pod uwagę treści zawarte w Księdze Henocha oraz Księdze Gigantów.The article presents a reinterpretation of Genesis 6:1-4 in the Book of Enoch. The book of Enoch broadly describes the context of the immoral conduct of mankind, described very synthetically in Genesis 6:1-4. It supplements information about giants not found in the Bible. The evil they committed and the size of the giants justify God's decision to send a flood to the world (Genesis 6:5-7). The article is an analysis of Genesis 6:1-4 taking into account the content contained in the Book of Enoch and the Book of Giants