A tumbler and pore water expression device to prepare homogeneous samples for the extraction of free chloride in cement paste

Published ArticleCorrosion of rebar in concrete is commonly associated with the free chloride in the pore water in the cement matrix. Knowing the quantity of chloride in concrete is important because chloride can promote corrosion of steel reinforcement when moisture and oxygen are present. The problem ofphysical extraction and the measurement of the free chloride content in pore water solutions extracted from cement pastes has received attention in literature but has not been explained in full detail. However, the variability of results obtained from the different methods used by various investigators only serves to confuse the issue. This investigation describes the use of a tumbler designed to prepare homogeneous samples and the use of a pore water expression device designed to extract free chloride in cement paste and concrete samples

Psalm 56 read within its literary context in the Psalter and its connections with King David

The heading of Ps 56 connects the psalm with “David,” and specifically with the time when he was “seized” by the Philistines in Gath. The psalm can be described as a lament with a strong emphasis on trust in God and praise for his word. This article investigates the reasons why the editors made this connection with the experience of David and how the intertextual connections this heading creates modifies the hermeneutical horizon of the psalm. It is suggested that the psalm, in view of its heading, serves to exonerate David from the fear that he experienced according to 1 Sam 21:13. It also focuses the attention of its readers on the way in which David triumphed in a situation of unjust persecution through his trust in Yahweh in order to walk freely in praise of God.http://reference.sabinet.co.za/sa_epublication/oldtestam201

The structure and homogeneity of Psalm 32

Psalm 32 is widely regarded as a psalm of thanksgiving with elements of wisdom poetry intermingled into it. The wisdom elements are variously explained as having been present from the beginning, or as having been added to a foundational composition. Such views of the Gattung have had a decisive influence on the interpretation of the psalm. This article argues, on the basis of a structural analysis, that Psalm 32 should be understood as a homogeneous wisdom composition. The parallel and inverse structure of its two stanzas demonstrate that the aim of its author was to encourage the upright to foster an open, intimate relationship with Yahweh in which transgressions are confessed and Yahweh’s benevolent guidance on the way of life is wisely accepted.http://www.hts.org.zahb201

“David” in consultation with the prophets : the intertextual relationship of Psalm 31 with the books of Jonah and Jeremiah

Psalm 31 seems to be a late post-exilic text. It displays numerous similarities with other psalms, and also with the prophetic books of Jonah and Jeremiah. This paper proposes to investigate the nature of the literary relationship with the prophetic books in an attempt to establish the direction of influence and to determine the reasons why the psalm seems to have been composed as a kind of literary anthology. It would seem that the group of people who were responsible for composing Ps 31 also contributed towards the insertion of the confessions of Jeremiah and the prayers of Jonah.http://www.journals.co.za/ej/ejour_oldtest.htmlnf201

The profile of the rich antagonist and the pious protagonist in Psalm 52

In this article, a stichometric and poetic analysis of Psalm 52 is offered which forms the basis for a description of the character of the rich but crooked antagonist and the pious protagonist in the psalm. The profile of the pious in the psalm emerges largely as the inverse of the inclination and actions of the arrogant, rich antagonist who is addressed in the greater part of the psalm. The psalm is also read and interpreted against the background of the book of Psalms as a whole to argue that Psalm 52 is actually describing the opposition between the righteous and the wicked as it is typically found in Wisdom psalms.http://www.hts.org.zaam201

Narratologiese ondersoek van die boek Jona

'Obwohl das Buch Jona sehr klein ist, hates der friihchristlichen Kunst und der Auslegung bis auf unsere Zeit vie/ Anregung gegeben; denn "dies scheinbar so alberne Biichlein gehort zu dem Tiefsten und Grossartigsten, was jemals geschrieben worden ist"' (my beklemtoning). Met hierdie woorde bring Loretz (1961:18) die paradoks tussen die lengte en die verstaanbaarheid van die boek treffend na vore. By die nagaan van die wetenskaplike literatuur oor Jona word hierdie paradoks al hoe duideliker. 'n Mens kom onder die indruk van die diversiteit van menings oor die boek wat gestalte vind in uitdrukkings soos 'the odd little tale' (Burrows 1970:80) en Luther se uitroep: 'Hilf Gott, welch ein wunderlich Werk is doch das!' (Von Rad 1974: 65). Daar is veral drie sake wat baie nou met mekaar saamhang, naamlik die komposisie, die literatuursoort en die boodskap, wat as probleemareas van die boek genoem word. Soveel uiteenlopende oplossings word vir hierdie drie probleemaspekte gebied dat daar inderdaad gese sou kon word dat daar 'n Babelse verwarring oor hierdie aspekte van die boek heers. As die lengte van die boek in ag geneem word, is dit inderdaad 'n vreemde en unieke situasie.hb201

Chloride-binding effect of blast furnace slag in cement pastes containing added chlorides

Corrosion of rebar in concrete is commonly associated with, and to a large degree influenced by, the free chloride concentration in the pore water. It is standard industry practice to add various mineral admixtures such as pulverised fuel ash (PFA), or fly ash, ground granulated blast furnace slag (GGBS) and silica fume (SF), to concrete mixtures to increase the corrosion resistance of the reinforcement in the matrix and its subsequent design life span. Various investigations have reported on the effect of mineral admixtures and additions on chloride binding in cementitious matrices, and the current study contributes further to knowledge in this field. Unlike previous investigations, this study attempted to make a clear distinction between the contributions of the two components in a blended cement consisting of ordinary Portland cement (OPC) and ground blast furnace slag (BFS). These contributions of each component have been quantified. Relationships between the total amount of chloride bound, the level of BFS additions, and the levels of initial chloride content present in the matrix were determined. It was found that the OPC/BFS blended cement with partial BFS replacements of up to 50%displayed a lower binding capacity than that of the OPC on its own. This observation was derived based on the assumption that theOPCand slag reactions were treated as competing and equivalent and did not take any potential time delays into account, nor the degree of cement hydration. The chloride-binding efficiency by the BFS is dependent on both the BFS partial replacement addition level as well as the initial amount of chloride present in the matrix. It is shown that both the OPC and BFS contribute to chloride binding in cement pastes, depending on the amount of BFS that replace the OPC component in the matrix.The authors express their gratitude to the NRF (National Research Foundation) for financial assistance.http://journals.sabinet.co.za/sajchem