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Effect of Fly-ash and Silica Fume on the Properties of Concrete Exposed to High Temperature 粉煤灰和硅灰对高温混凝土性能的影响

Silicates Industriels Pub Date : 2008-01-01 DOI: 10.21608/absb.2007.11107

M. Taher

{"title":"Effect of Fly-ash and Silica Fume on the Properties of Concrete Exposed to High Temperature","authors":"M. Taher","doi":"10.21608/absb.2007.11107","DOIUrl":"https://doi.org/10.21608/absb.2007.11107","url":null,"abstract":"The development of high temperatures in concrete could cause a number of effects that have been shown to be determining to long-term concrete performance. High temperatures in concrete increase the rate of hydration, thermal stresses, the tendency for drying shrinkage cracking, permeability, and decrease of long-term concrete strengths and durability as a result of cracking. The objective of this study is to investigate the effects of using fly-ash and silica fume on the strength and absorption of cement concrete and pozzolanic cement concrete in hot condition. The cement concrete and pozzolanic cement concrete specimens containing fly-ash or silica fume were first cured in water for a periods of 1, 3, 7, 28, 90 and 180 days then exposed to high temperature 45°C ( maximum summer temperature in Egypt and Arabian Gulf countries) in oven for 2,8,12 and 24 hours. The effect of fly-ash and silica fume contents on the absorption capacity of concrete specimens was evaluated by measuring 48-hours absorption and volume of permeable voids. The specimens were also tested for compressive strength and moisture content. The results show an increase in the compressive strength of cement concrete and pozzolanic cement concrete with increasing both curing and exposing temperature time. The absorption of theses concretes decreased with time of curing and increased with exposing temperature time The absorption of both fly-ash and silica fume cement concrete specimens decreased significantly at early stages (3-7days) of curing. While the absorption of cement concrete specimens were effected significantly by exposing temperature period, no significant change in the absorption of pozzolanic cement concretes due to increasing exposing temperature period was observed, especially after 7 days of curing. The volume of permeable voids also decreased with curing. The highest reduction in the absorption and volume of voids was observed in the fly-ash concrete specimens.","PeriodicalId":21741,"journal":{"name":"Silicates Industriels","volume":"6 1","pages":"177-183"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89961397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

In-situ carbon content adjustment in polymer-derived Si/C/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition 反应热处理原位调整聚合物基Si/C/N陶瓷中的碳含量。热解产物组成计算

Silicates Industriels Pub Date : 1999-01-01 DOI: 10.1016/s0140-6701(01)80600-7

D. Galusek, S. Reschke, R. Riedel

引用次数: 1

Effect of Calcining Temperature of Kaolinite Clay on the Properties of Portland Cement Pastes Containing Metakaolin 高岭土煅烧温度对偏高岭土硅酸盐水泥体性能的影响

Silicates Industriels Pub Date : 1900-01-01 DOI: 10.21608/absb.2007.11149

M. Taher, A. Y. El-Sayed, O. A. Farghaly, M. Shatat

{"title":"Effect of Calcining Temperature of Kaolinite Clay on the Properties of Portland Cement Pastes Containing Metakaolin","authors":"M. Taher, A. Y. El-Sayed, O. A. Farghaly, M. Shatat","doi":"10.21608/absb.2007.11149","DOIUrl":"https://doi.org/10.21608/absb.2007.11149","url":null,"abstract":"Metakaolin (MK) is a highly reactive pozzolan produced by calcination of kaolinite clay at high temperature. It has a high specific surface, which makes it very suitable as a cementing material in concrete. The utilization of calcined clay, in the form of MK, as a pozzolanic material for mortar and concrete has received considerable attention in recent years. This interest is part of the widely spread attention directed towards the utilization of wastes and industrial by-products in order to minimize Portland cement (PC) consumption, the manufacture of which being environmentally damaging. Another reason is that mortar and concrete, which contain pozzolanic materials, exhibit considerable enhancement in durability properties. In this investigation, the physicochemical properties of artificial pozzolanic cement pastes containing MK produced by calcination of kaolinite clay at different temperatures (700, 800, 900, and 1000°C) were studied. PC was partially substituted for by 0, 5,10,15 and 20 % ofMK by weight at different calcining temperatures. The characteristics of prepared mortars were investigated after curing in water for different periods (3, 7, 28 and 90 days) by determination of compressive strength and total porosity. The hydration kinetics was evaluated by determination of free lime contents. IR spectroscopic analysis was used to investigate the change in structure of mortars after curing. The change in morphology and microstructure of some hardened pastes were investigated by scanning electron microscopy (SEM) tests.","PeriodicalId":21741,"journal":{"name":"Silicates Industriels","volume":"14 1","pages":"32-39"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82036393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2