Keywords: calcium sulfoaluminate cement, hydration, retarders, compressive strength, setting time. 1 Introduction . Although OPC (Ordinary Portland Cement) is the most …
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The setting times of the mixes are found to be lower than that of the value prescribed for ordinary Portland cement (OPC). Borax is used as a setting retarder and a borax content of 0.4 % by mass gives setting times that are normally prescribed for OPC.
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For the OPC samples that were treated with a surface retarder, growth is mostly concentrated on the cement part of the surface, not the aggregate. This holds especially true for the samples with the regular limestone aggregate, where growth takes place exclusively on the cement.
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A set retarder which also had some plasticising properties, namely Pozzolith 300R, was used in the mixes, because it was envisaged that the concretes tested would be used by ready-mixed concrete companies. A retarder dosage of 3 ml=kg of OPC was used for mix design trials and durability testing.
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Introduction Ordinary Portland cement (OPC) is a crucial ingredient in the construction materials concrete and mortar. 1 It comprises several compounds, including silicate, …
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Retarder increases the initial setting time of cement while accelerators reduces the setting time of cement. Some commonly used retards are: Organic retardants include unrefined calcium, sodium, NH 4, salts of lignosulfonic acids, hydrocarboxylic acids, and carbohydrates.. Inorganic retardants include oxides of lead and zinc, phosphates, …
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One of the most important uses of natural gypsum is the manufacture of ordinary Portland cement (OPC), which is included in amounts of 2.5-5%, acting as an OPC setting time retarder [42, 43]. If ...
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Request PDF | A plant investigation into the use of treated phosphogypsum as a set-retarder in OPC and an OPC/FLY ash blend | This investigation describes the successful substitution of ...
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concrete binders using OPC and CSA binders at low temperatures. In addition, this study aims to validate the applicability of CSA in concrete by reviewing various factors, such as the optimum binder, accelerator, and retarder through mortar experiments for early strength development. 2. Experimental Work 2.1. Materials
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Ordinary Portland cement (OPC) is advantageous in that it exhibits favorable physical properties and strength due to its stable chemical reactions, thereby leading to a wide applicability. ... However, Figure 11 shows that the compressive strength of the concrete using the retarder was lowered. It may therefore be possible to …
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OPC paste with a water cement ratio 0.4 to 0.5 was prepared by mixing 500 grams of ordinary Portland cement, a fixed amount of sugar of 0.02% by weight of cement with a combination of different ...
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The efficacy of date kernel powder (DKP) as a retarder in OPC concrete mixes, by replacing cement at percentages ranging from 0.5% to 5%, and its effect of the fresh and hardened properties including the workability, density, setting times, heat of hydration, mechanical and thermal properties are presented.
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Lee et al. [25] prepared 3D concrete materials by mixing 0.2% citric acid (retarder), 2% sodium sulfate (accelerator), and 17% calcium sulphoaluminate with ordinary Portland cement ...
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Sika® Retarder-22 is a phosphate based liquid admixture that slows the cement hydration; delaying the initial set in direct proportion to the dosage used. ... Sika® Retarder-22 may be combined with all types of Portland cement (OPC and SRC), concretes containing pozzolanic materials such as GGBS, PFA, micro-silica and the following Sika products:
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setting and/or hardening of Ordinary Portland Cement (OPC) and OPC based concrete. Both ... a retarder, at 0.5 % as a severe retarder and at 1.0 % as a flash-set accelerator. Similar behaviour .
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Gypsum is the set retarder for ordinary portland cement (OPC). Without gypsum, ground clinker exhibits flash setting in a few minutes, due to the rapid hydration of
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In contrast, the CSA cement replacement for OPC was much lower as 10% in this study. On the other hand, the excessive amount of CSA cements in the blend may lead to uncontrollable rapid set of the binder, and thus the use of set-retarder is necessary for feasible use of CSA in OPC blends.
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A plant investigation into the use of treated phosphogypsum as a set-retarder in OPC and an OPC/Fly Ash blend Min. Eng., 14 ( 7 ) ( 2001 ), pp. 791 - 795 View PDF View article View in Scopus Google Scholar
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Key Takeaways • OPC and PPC cement are crucial for construction, influencing structure durability and strength. • Ordinary Portland Cement (OPC) is versatile, coming in grades like OPC 33, 43, and 53, each with distinct strengths. • Portland Pozzolana Cement (PPC) offers benefits like lower heat of hydration and enhanced resistance to chemicals.
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The citric acid was used as a water reducer, setting time retarder and workable time extender admixture on ordinary Portland cement (OPC). The changes in compressive strength, permeability and ...
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The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3–5 wt% of WG was ground in a laboratory ball …
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The following naming convention is used: OPC stands for a sample that does not contain any SCM; OPC + WSA650, OPC + RSA650, and OPC + RSA500 represent samples that contain 15% of WSA650, RSA650, and RSA500 replacement of cement, respectively.Similarly, OPC + MK, OPC + SF, and OPC + FA are samples that contain …
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In the manufacture process of cement, clinkers are formed. These cement clinkers are cooled down and added with small amount of gypsum. The mixture then sent to final grinding process. For ordinary Portland cement it remains between 3 to 4% and in case of Quick setting cement it can be reduced up to 2.5%. Role of Gypsum in Cement
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Adsorption has been demonstrated (6) in the case of glucose and Ordinary Portland Cement (OPC) in that the zeta potential of hydrating cement grains, normally found to be positive, became negative in the presence of glucose. ... One of the key factors often associated with a good retarder of cement hydration is calcium complexing ability …
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The results of a study conducted by Arpana et al. [19] on the use of sugar in concrete as retarder demonstrated that the setting time of concrete increases with increase in the percentage of sugar up to 0.06%. However, both initial and final setting time severely reduces with increase in the sugar content beyond 0.06%.
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Previous research has shown that accelerators in concrete promotes Early strength of concrete with OPC and secure its constructability using additional retarders to control the quick setting of ...
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This study extended blending proportion range of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement blends, and investigated effects of proportions on setting time, workability, and strength development of OPC-CSA blend-based mixtures. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were …
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In this article the progress of the research on cement hydration mechanisms is critically reviewed, starting with the work of Le Chatelier and Michaelis during the late nineteenth century. Proposed mechanisms are discussed in the light of experimental data to highlight the role of new or improved analytical techniques. The focus of this article lies …
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Cement shrinkage is a cause of gas migration in OPC systems. Shrinkage is mostly caused by the reduction in cement volume as the water gets taken up by the hydrated cement products (e.g., ettringite and calcium silicates) during hardening, however, the geopolymer hardening process is different (Salehi et al., 2017).
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The retarder effect of Na 2 CO 3 is attributed to the reactions between Ca 2+ dissolved from BFS and CO 3 2 ... Conversely, if the OPC concrete in Fig. 6 was used as reference, flexural strength of the AAF concrete synthesized by Diaz-Loya et al. [106], Haruna et al. ...
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of Retarder for Alkali-Activated Cement Klaus Holschemacher 1( B ) and Biruk Hailu Tekle 1,2 1 Structural Concrete Institute, Leipzig University of Applied Sciences (HTWK Leipzig), 04277
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HyCon® R 3100 F is a construction additive retarder in powder form. It is a setting retarder selectively delaying the gypsum formation, without affecting the subsequent hardening of ordinary Portland cement (OPC). It is used for retardation of binary flowable dry mortar products to adjust the desired workability time. HyCon® R 3100 F is designed for binder …
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