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Their presence decreased the autogenous shrinkage of cement mortar by reducing the surface tension of pore solution, delaying the cement hydration, and decreasing the capillary pore volume. Their addition also mitigated the drying shrinkage due to the synergistic effect of surface tension reduction, pore structure coarsening, and …
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Autogenous shrinkage is an important factor for cracking of cement-based materials at early ages. This review summarizes different definitions and testing methods for autogenous shrinkage in literature. Autogenous shrinkage should be defined as the sum of chemical shrinkage and self-desiccation shrinkage.
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Heat generated as a result of the exothermic reaction associated with cement hydration accelerates the autogenous shrinkage of the concrete [42, 43] and may result in the formation of micro-cracks [[44], [45], [46]]. To examine the exothermic reaction of the UHPCs, a thermal sensor was embedded at the center of a 100 mm cubic specimen.
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5.1 Autogenous strain is the self-created bulk strain of cement paste, mortar, or concrete during hardening at constant temperature. In conventional concrete, autogenous shrinkage strain is generally negligible, but in concrete with low water-cementitious materials ratio (w/cm) or with silica fume it may be considerable (1). 5 …
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1. Introduction. Autogenous shrinkage refers to reduction of apparent volume or length of cement-based materials under seal and isothermal conditions [1].It …
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2.2. Autogenous Shrinkage. As reported by the Japan Concrete Institute (JCI), AGS is the macroscopic volume reduction in cement during early hydration at the …
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Semi autogenous mill is mainly used in non-ferrous metals, mining, metallurgy, cement and other industries. The semi autogenous mill has the advantages of large crushing ratio, high efficiency, low energy consumption, uniform product size, and suitable for crushing and fine crushing of various ores and rocks
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Corrections on the data are needed afterwards (A.1) ε c t = ε aso f cm ∙ β as t where ε c (t) is the autogenous shrinkage of concrete; f cm is the mean compressive strength of concrete at an age of 28 days, which is 91.4 MPa and 75.2 MPa for AAS and AASF concrete, respectively [98]; ε aso (f cm) is the notional autogenous shrinkage ...
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SAG mills, or Semi-Autogenous Grinding mills, use a combination of steel balls and rock particles to grind ore. ... and platinum group metals. They are also used in the cement industry and other industrial sectors. AG mills, on the other hand, are often used in the mining industry for the processing of precious metals such as gold and silver ...
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The VSI crusher is primarily a third or fourth stage crusher. Some, but by no means all, of the applications of this crusher are: • Manufactured sand • Premium shaped aggregates (concrete and road products) • Recycling industry • Industrial minerals industry • Mining industry The autogenous "rock on rock" crushing technique ...
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Calcium sulfoaluminate (CSA) cement can be used as an alternative binder in concrete, partially or fully replacing ordinary Portland cement. While CSA cement considerably accelerates the mechanical properties development, the rapid evolution of the microstructure together with the high water demand cause rapid and large volume …
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The autogenous shrinkage and microstructure of Na 2 SO 4-Na 2 O·1.5SiO 2 ... into small pieces at 1, 6, 12, and 24 hours, and at 3 and 7 days. Then, the small test blocks were …
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The autogenous shrinkage of SSC concrete developed rapidly within the initial 4 d, followed by a deceleration in the development rate after 4 d. The autogenous shrinkage of SSC concrete at 13.93 d was − 78, − 66, − 60, and − 52 με for SSC concrete with GBFS substitution rates of 0%, 15%, 30%, and 50%, respectively.
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1. Introduction. Autogenous shrinkage is a main reason for the cracking of high-performance concrete; indeed, the autogenous shrinkage of high-performance concrete is often appreciable at an early age owing to a low water-to-cement (W/C) ratio (e.g., <0.4) and a high content of pozzolans, such as silica fume [1], [2].There is …
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The Williams Reversible Nuggetizer® Crusher (U.S. Patent No. 3,667,694) is a rugged primary, single-stage impact crusher capable of a broad range of crushing applications including cement, rock, limestone, coal, …
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The addition of supplementary cementitious materials (SCMs), which is an effective method to reduce the CO 2 emission during the cement production, will change the autogenous shrinkage of early-age hydrating cementitious systems. In this paper the effect of different SCMs, i.e., silica fume and fly ash, on the physical properties and …
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When "A dilatometer for measuring autogenous deformation in hardening Portland cement paste" by Ole Mejlhede Jensen and Per Freiesleben Hansen [] was published in Materials and Structures in 1995, autogenous shrinkage was about to become a trendy topic in concrete research [].In the same year, in Cement and Concrete …
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Concrete consists of two parts: shrinking cement paste matrix and non-shrinking sand/aggregate particles. In future studies, with the knowledge of autogenous shrinkage of cement paste, the autogenous shrinkage of concrete can be predicted by taking the restraining effect of non-shrinking sand/aggregate particles into consideration.
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Autogenous shrinkage of concrete refers to the reduction of apparent volume or length of cement-based materials in seal and isothermal conditions. ... (RCAs): …
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1. Introduction. Autogenous shrinkage refers to the reduction of macroscopic volume of concrete caused by chemical shrinkage and self-desiccation due to the continuous hydration of cement paste in the environment of constant temperature and humidity [[1], [2], [3]].The phenomenon of autogenous shrinkage in ordinary concrete is …
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This paper leads to the followingfindings: 1) The autogenous deformation of ordinary Portland cement paste is a four-stage process comprising theinitial shrinkage, autogenous expansion, plateau ...
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This study aims to disclose the working mechanisms of a novel shrinkage-reducing polycarboxylate superplasticizer (SR-PCA) in mitigating autogenous shrinkage of cement paste. The properties of pore solutions (-including the surface tension and contact angle), ions concentration in pore solutions, internal relative humidity (RH), dynamic …
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In the case of concrete, the process can be autogenous, based on optimized mix composition, or autonomous, when using additionally incorporated capsules containing a healing agent and/or bacteria spores. The first process uses unhydrated cement particles as the healing material while the other utilizes a synthetic material or …
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The roller crushers are used for moist and sticky materials. Generally the machines have to be rigid enough to crush also hard inclusions. As the reduction ratio is only about 5:1 a 2-stage crushing is required in most applications. …
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The autogenous shrinkage of cement paste with 0.3, 0.4, and 0.5 w/c ratios. Fig. 3 and Fig. 4 show the autogenous shrinkage results of mortar and gravel concrete with a w/c ratio of 0.4, respectively. The label P40S25 indicates mortar with a w/c ratio of 0.4 and a sand volume fraction of 25%. P40G10 indicates gravel concrete with a …
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Autogenous shrinkage cement pastes and Mortar: Corrugated tubes. The autogenous shrinkage of the tested cement pastes and mortar mixtures was monitored continuously over a time period of 7 days by means of a corrugated tubes test following the standard ASTM C 1698-09 [52]. A flexible corrugated mould and a dilatometer, namely …
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