"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference"最新文献_第4页

Monitoring Setting and Early Hydration of Cement Using Dielectric Spectroscopy 介电光谱法监测水泥凝结及早期水化

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10578

S. Ng, G. Shapiro, S. Mak

引用次数: 3

Rapid Microwave Curing of Precast Concrete Slab Elements 预制混凝土板构件的快速微波养护

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10600

S. Mak, D. Ritchie, G. Shapiro, R. W. Banks

{"title":"Rapid Microwave Curing of Precast Concrete Slab Elements","authors":"S. Mak, D. Ritchie, G. Shapiro, R. W. Banks","doi":"10.14359/10600","DOIUrl":"https://doi.org/10.14359/10600","url":null,"abstract":"The speed of curing is often a critical issue in the manufacture of precast concrete elements. For some products, the curing cycle consumes up to 70% of the total production cycle. To improve the speed of production, heat curing is often used to accelerate the hardening of precast concrete. Conventional heating techniques rely on thermal conduction. Microwave energy offers potential to increase the rate of bulk heating in precast concrete through its relatively deeper penetration, which allows quicker through-depth heating and maturing. Research on microwave curing of concrete has been ad hoc in the past and a wide range of issues remain unresolved. These encompass materials-microwave interactions, process design and control, hardware and logistics as well as the impact of microwave curing on concrete properties. In this paper, progress on research on microwave curing is described with reference to work carried out at CSIRO. In particular, results from pilot-scale heating of slab-type elements are discussed in relation to heating characteristics, process control, set acceleration, strength development and process efficiency. The authors' results show that for the same bulk heating rates, microwave heating produces significantly lower temperature gradients when compared to steam heating. Using rapid curing cycles of less than six hours, compressive strengths in excess of 25 MPa can be achieved in high quality precast concrete. Doubling the bulk heating rate using microwaves does not result in any deterioration in near-surface quality as was the case with conventional steam heating.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124999619","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: 6

Chloride Diffusivity of Concrete Incorporating Rice Husk Ash 稻壳灰混凝土的氯离子扩散系数

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10585

N. Maeda, I. Wada, M. Kawakami, T. Ueda, G. Pushpalal

{"title":"Chloride Diffusivity of Concrete Incorporating Rice Husk Ash","authors":"N. Maeda, I. Wada, M. Kawakami, T. Ueda, G. Pushpalal","doi":"10.14359/10585","DOIUrl":"https://doi.org/10.14359/10585","url":null,"abstract":"Effect of rice husk ash addition on the chloride diffusivity of concrete is investigated in the present paper. The concrete specimens, having water-cementitious materials ratio of 0.30, 0.36 and 0.53, with and without rice husk ash are subjected to accelerated chloride penetration using the following two methods: i) Immersion in saturated NaCl at 20 degrees C, ii) Exposure to alternate cycles of 3 days immersion in 3% NaCl solution at 20 degrees C and 4 days drying at 50% R.H. After the accelerated chloride penetration, the total chloride content of concrete specimens at various depths was determined. Consequently, using the chloride content distributions, the chloride diffusion coefficient of concrete is evaluated by applying Fick's second law. In addition, the pore size distribution of concrete is determined in order to assess the effect of concrete microstructure on chloride diffusivity. From the experimental results, the total chloride content of concrete incorporating rice husk ash was shown to be lower than that of the control concrete after accelerated chloride penetration. The concrete specimens incorporating rice husk ash had chloride diffusion coefficients 57% to 25% lower than the control concrete. The effect of rice husk ash on pore refinement in concrete was observed, especially in the pore radii larger than 50nm. The pore size distribution of concrete tended to shift towards the smaller pores with the addition of rice husk ash. The decrease of the chloride diffusion coefficient of concrete incorporating RHA may therefore be attributed to the pore-refinement effect.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129608465","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: 9

Use of Glass and Fly Ash in Manufacture of Controlled low Strength Materials 玻璃和粉煤灰在控制低强度材料制造中的应用

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10588

T. Naik, R. N. Kraus, Shiw S. Singh

{"title":"Use of Glass and Fly Ash in Manufacture of Controlled low Strength Materials","authors":"T. Naik, R. N. Kraus, Shiw S. Singh","doi":"10.14359/10588","DOIUrl":"https://doi.org/10.14359/10588","url":null,"abstract":"This work was conducted to develop two types of controlled low strength materials (CLSM) or flowable slurry utilizing post-consumer glass (broken glass or glass cullet) aggregate and fly ash. Type A CLSM consisted of glass, fly ash, cement, and water; and Type B CLSM consisted of glass, sand, cement, and water. All mixtures were proportioned to achieve the 28-day compressive strength of 0.7 MPa (100 psi). The type A CLSM mixtures consisted of a control mixture (100% fly ash without glass) and five other mixtures with glass, as a replacement of fly ash in the range of 20% to 80%. The Type B CLSM mixtures were composed of a control mixture (without glass) and two other mixtures at 30% to 75% replacement of sand with glass. The flowable slurry developed in this project satisfied the ACI Committee 229 definition of CLSM. Decreasing the amount of fly ash and increasing the glass content led to increased bleeding and segregation at high replacement levels of 60% and 80%. Permeability of Type A CLSM remained essentially unchanged, except at high glass contents it was lower. For Type B CLSM, the permeability was about the same.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"42 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126214337","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: 10

Axial Compressive Behavior of Reinforced Concrete Short Columns Strengthened with Carbon Fiber Sheets 碳纤维板加固钢筋混凝土短柱轴压性能研究

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10595

J. Hwang, K. S. Lee, B. Bahn, S. Shin

引用次数: 0

The U.S. Power Industry’s Activities to Expand Coal Ash Utilization in Face of lower Ash Quality 面对煤灰质量下降，美国电力工业扩大煤灰利用的活动

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10584

D. Golden

引用次数: 2

Durability of Reactive Powder Concrete When Subjected to a leaching Test 活性粉末混凝土经受浸出试验时的耐久性

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10593

Matte, M. Cheyrezy, M. Moranville, C. Richet, J. Torrenti

引用次数: 2

Use of Recycled Concrete Powder in Self-Compacting Concrete 再生混凝土粉在自密实混凝土中的应用

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10590

H. Kasami, M. Hosino, T. Arasima, H. Tateyasiki

{"title":"Use of Recycled Concrete Powder in Self-Compacting Concrete","authors":"H. Kasami, M. Hosino, T. Arasima, H. Tateyasiki","doi":"10.14359/10590","DOIUrl":"https://doi.org/10.14359/10590","url":null,"abstract":"Although 37 million tons of concrete wastes have been generated annually in Japan, the use of recycled aggregate for concrete is limited because of low density and high absorption due to adhered cement paste and mortar. A new method to produce high quality recycled aggregate by heating and grinding concrete rubbles to separate cement portions adhering to aggregate was developed recently. In this process, by-product powder with the fineness of 400 m2/kg is generated. By-product recycled concrete powder consists of fine particles of hydrated cement and crushed aggregate. To utilize the recycled concrete powder as concrete additives two series of experiments were performed to make clear the effect of recycled powder. Self-compacting concrete with recycled concrete powder, ground blast-furnace slag and ground limestone were tested for slump-flow, compressive strength, modulus of elasticity and drying shrinkage. Reduction in superplasticizing effect of high-range water reducer was found for concrete with recycled concrete powder. Compressive strength of concrete with recycled concrete powder was the same as those with ground limestone, and lower than those with ground slag. Concrete with recycled concrete powder showed lower elastic modulus and higher drying shrinkage than those with ground slag and ground limestone. The recycled concrete powder is usable for self-compacting concrete without further processing, despite the possible increase in dosage of high-range water reducer for a given slump-flow and in drying shrinkage. The addition of ground blast-furnace slag together with recycled concrete powder to self-compacting concrete improved superplasticizing effect of high-range water reducer and properties of concrete.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"65 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131775810","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: 13

Mechanical Properties of Concrete Containing Foundry Sand 含铸造砂混凝土的力学性能

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10612

J. Khatib, D. J. Ellis

{"title":"Mechanical Properties of Concrete Containing Foundry Sand","authors":"J. Khatib, D. J. Ellis","doi":"10.14359/10612","DOIUrl":"https://doi.org/10.14359/10612","url":null,"abstract":"The properties of concrete containing foundry sand as a partial replacement of fine aggregate were investigated. Three types of sand used in foundries were considered, the white fine sand without the addition of clay and coal, the foundry sand before casting (blended), and the foundry sand after casting (spent). The standard sand (Class M) was partially replaced by (0%, 25%, 50%, 75%, and 100%) these types of sand. Thirteen concrete mixtures were employed to conduct this study. Concrete strength up to 90 days and length change (drying shrinkage and expansion) up to 60 days were determined. As the replacement level of standard sand with sand used in foundries increased, the strength of concrete decreased. Concrete containing white sand showed somewhat similar strength to those containing spent sand at all replacement levels. The presence of high percentage of blended sand in the concrete mixture caused a reduction in strength as compared with concrete incorporating white sand or spent sand. The increase in strength was not observed at low replacement levels (less than 50%). The length change of concrete increased as the replacement level of standard sand with the three types of sand increased. Drying shrinkage values were higher in concrete containing spent sand and lower in concrete containing white sand. Expansion was generally lower in concrete containing white sand as compared with the other two types (blended and spent) at a low sand replacement level of 25%; and, a different trend was obtained at higher levels.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126026551","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: 88

Expansion of Powerhouse Structures Due to Alkali-Aggregate Reaction and the Use of low Calcium Fly Ash to Ameliorate the Reaction in Future Construction 碱-骨料反应引起厂房结构膨胀及在今后施工中使用低钙粉煤灰改善反应

"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference" Pub Date : 2001-06-01 DOI: 10.14359/10576

W. Langley, E. Brown

引用次数: 0