SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology最新文献_第2页

New Super-plasticizers Based on Modified Melamine Polymer 基于改性三聚氰胺聚合物的新型高效增塑剂

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6042

I. Torresan, R. Khurana

{"title":"New Super-plasticizers Based on Modified Melamine Polymer","authors":"I. Torresan, R. Khurana","doi":"10.14359/6042","DOIUrl":"https://doi.org/10.14359/6042","url":null,"abstract":"Admixtures based on sulfonate melamine formaldehyde condensate polymer (SM) have been available commercially for more than three decades. These products are widely used by the precast concrete industry, but with some limitations on slump retention and early strength. To improve these properties, synthesis of a modified sulfonate melamine formaldehyde condensate polymer (MSM) was performed. In this paper its physical and chemical characteristics are reported. Dispersibility and adsorption tests, using cement pastes, were carried out to compare the superplasticizing effect of the new MSM polymer against the SM polymer. Concrete mixtures were also made to evaluate the performances of this MSM polymer in comparison with the other types of superplasticizers such as SM and beta-naphthalene sulfonate formaldehyde condensate (SN). Results of these tests show that MSM polymer has a better water reduction capacity, lower air content in the fresh concrete and higher early strength at 1 day as compared to the other superplasticizers under the test conditions. These characteristics are very much desired by the precast industry for easy placement of concrete and quick turn around of the formworks. Field tests also reported, confirm the laboratory findings.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116963119","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

Properties of High-Strength Porous Concrete 高强多孔混凝土的性能研究

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6038

H. Fujiwara, R. Tomita, T. Okamoto, A. Dozono, A. Obatake

引用次数: 15

Shrinkage Reduction Type of Advanced Superplasticizer 减缩型高级高效减水剂

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6039

T. Sugiyama, A. Ohta, Y. Tanaka

引用次数: 7

Studies of Polymer Cement Mortar for use as Permanent Forms 聚合物水泥砂浆永久成型材料的研究

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6071

K. Horii, T. Tsutsuzaki, K. Kohno

{"title":"Studies of Polymer Cement Mortar for use as Permanent Forms","authors":"K. Horii, T. Tsutsuzaki, K. Kohno","doi":"10.14359/6071","DOIUrl":"https://doi.org/10.14359/6071","url":null,"abstract":"The purpose of this paper is to develop pre-casting permanent forms which are effective in improving the durability and appearance of concrete structures, conserving wood and modernizing cast-in-place concrete work. The influences of various materials used and accelerated curing methods on the properties of polymer cement mortar (PCM) applied to the forms were investigated. In these experiments, polymer dispersions composed of styrene-acryl (SA), polyacrylic ester (PAE), ethylene-vinyl acetate (EVA) and styrene-butadiene rubber (SBR) were used. Mixtures contained aggregate - crushed silica and ferro-nickel slag sand; cement - normal portland, high-early strength portland and white portland cement; and color pigment - red, green, yellow and black. Steam curing and oven-dry curing were carried out. The fluidity, compressive strength, flexural strength, resistance to abrasion, chloride ion penetration, carbonation and sulfate resistance, and surface color of PCM were examined. From these investigations, the following conclusions were obtained: The use of SA type polymer, ferro-nickel slag sand, high-early strength portland cement and color pigments were effective in getting PCM with high fluidity, mechanical strength, durability and tinting strength. Additionally, steam curing and oven-dry curing are practical for the early-age strength development of PCM.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128027972","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

Application of Infrared Thermography Technique for Evaluation of Cracks in the Concrete Structures 红外热成像技术在混凝土结构裂缝评价中的应用

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6059

S. Nagataki, T. Kamada, A. Matsumoto

引用次数: 0

Determination of the Apparent Activation Energy of Concrete: Ea. Semi-Adiabatic Tests of Heat Development 混凝土表观活化能的测定。热发展的半绝热试验

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6061

L. D'aloia, G. Chanvillard

{"title":"Determination of the Apparent Activation Energy of Concrete: Ea. Semi-Adiabatic Tests of Heat Development","authors":"L. D'aloia, G. Chanvillard","doi":"10.14359/6061","DOIUrl":"https://doi.org/10.14359/6061","url":null,"abstract":"The \"method of equivalent age\" is one of the currently used nondestructive testing methods of concrete strength estimation. It is based on Arrhenius' law, which has shown itself to be the most accurate in describing the influence of temperature on concrete strength development at early ages. A proper estimation is directly related to a correct determination of the Apparent Activation Energy: Ea. This is the unique parameter which characterizes the concrete mixture and which can be found in Arrhenius' law. The major aim of this paper is to show how calorimetric tests under semi-adiabatic conditions can be an alternative to unwieldy compressive test procedures in determining Ea. The validity of the obtained Ea values has been verified by means of several mechanical tests. Moreover, the possibility of using either mortar or concrete is partially dealt with. The water to cement ratio appears to naturally be considered as a constant in proportioning an equivalent mortar. Finally, the evolution of the Apparent Activation Energy in relation to the degree of hydration is given. Hence, the widespread opinion that Ea depends on the degree of hydration is confirmed and a field of definition can be brought to the fore.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121625940","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

Use of a Water-Repellent Admixture to Improve Concrete Performance 使用防水外加剂改善混凝土性能

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6041

M. Shoya, S. Sugita, Y. Tsukinaga, M. Aba, M. Ohba

引用次数: 2

High-Performance Concrete Mixture Proportioning 高性能混凝土配合比

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6053

K. Sobolev, S. Soboleva

{"title":"High-Performance Concrete Mixture Proportioning","authors":"K. Sobolev, S. Soboleva","doi":"10.14359/6053","DOIUrl":"https://doi.org/10.14359/6053","url":null,"abstract":"The report generalizes the results of wide range investigations of silica fume based superplasticized high-performance concrete. The rules of the strength and rheological behavior of cement - silica fume - superplasticizer systems are discussed. Usage of optimal superplasticizer to silica fume ratio (as 1:10) allows to obtain ultra-dense packing for super fluid cement paste and provides high-performance properties of concrete. The mathematical models of fresh and hardened high-performance concrete based on processing and computerizing empirical results are created. The models provide a calculation of water/cement ratio required for the target compressive strength level up to 130 MPa as well as mixing water quantity for planning slump of 0-200 mm. For modelling purpose, concrete slump is considered as a function of aggregates proportioning, and volume and fluidity of cement paste. This approach became a basis of proposed high-performance concrete mixture proportioning method. Further, developing and integration of the mathematical models created a new computer program for high-performance concrete mixture proportioning. The program provides a solution for wide range design and optimization projects. The results of the computer program estimation can be easily transferred to any 3-dimensional plotting or data base program for consequent processing and performing.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132764714","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: 8

Relationship Between Neutralization Depth and Concentration Distribution of CaCO3 -Ca(OH)2 in Carbonated Concrete 碳化混凝土中和深度与CaCO3 -Ca(OH)2浓度分布的关系

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6049

T. Fukushima, Y. Yoshizaki, F. Tomosawa, K. Takahashi

{"title":"Relationship Between Neutralization Depth and Concentration Distribution of CaCO3 -Ca(OH)2 in Carbonated Concrete","authors":"T. Fukushima, Y. Yoshizaki, F. Tomosawa, K. Takahashi","doi":"10.14359/6049","DOIUrl":"https://doi.org/10.14359/6049","url":null,"abstract":"The relationship between the neutralization depth determined by a phenolphthalein 1% ethanol solution and the concentration distribution of CaCO3-Ca(OH)2 in carbonated concrete is discussed, based upon accelerated carbonation and outdoor exposure tests, and field survey research by making use of powder X-ray diffraction and thermal analytical methods. It was found that the neutralization depth exists in the partly carbonated zone of concrete where both CaCO3 and Ca(OH)2 are observed, and that carbonation front depth from which CaCO3 is not detected, exists much deeper in concrete. Further, it was confirmed that the neutralization depth is about half of the carbonation front depth. This fact is interpreted by theoretical research of unsteady state dynamic analysis for the diffusion of CO2 from the surface inwards into concrete accompanied by carbonation reaction with Ca(OH)2. Computer simulation was done for the converted CO2 concentration in carbonated concrete by using the effective diffusion coefficient estimated as a function of water cement ratio. If the converted CO2 concentration in the neutralization depth is assumed to be 10% of the surface concentration, the neutralization depth is almost the same as the depth calculated using Hamada's law which is considered to be adequately applicable for the progress of neutralization of concrete with a water cement ratio of 60% exposed outdoors in the rain. It is concluded that the relationship between the neutralization depth (X sub n) and the carbonation front depth (X sub f) is expressed by the following equation: X sub n = (1/2) X sub f.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130360773","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: 22

"Carbonation, Amount of Chloride Ion, and Corrosion of Steel Reinforced Concrete Buildings in HANSHIN Region" 阪神地区钢筋混凝土建筑的碳化、氯离子量与腐蚀

SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology Pub Date : 1998-06-01 DOI: 10.14359/6047

Y. Ohno, Y. Yamamoto

{"title":"\"Carbonation, Amount of Chloride Ion, and Corrosion of Steel Reinforced Concrete Buildings in HANSHIN Region\"","authors":"Y. Ohno, Y. Yamamoto","doi":"10.14359/6047","DOIUrl":"https://doi.org/10.14359/6047","url":null,"abstract":"Many reinforced buildings were damaged by the Hygoken-Nanbu Earthquake of 1995. In order to clarify the actual state of carbonation of the concrete and the chloride ion content in concrete of buildings in the Hanshin area, the depths of carbonation and the amount of chloride ion were measured in 117 concrete samples that were obtained from 97 damaged buildings. The effects of carbonation depth and chloride ion content with regard to the corrosion of steel were also investigated. The measured carbonation depths were wildly scattered, with some of the concrete being heavily carbonated. The amounts of chloride ions in old river sand concrete were small. Large amounts of chloride ion were found mixed with sand, that came not only from the ocean but also from rivers, in the buildings that were built between 1960 and 1978. This chloride ion was thought to be induced through sea sand and an admixture. The concentration of chloride ions in concrete were small for buildings that had been constructed after the regulation of the amount of chloride in concrete that was instituted in 1986. A great deal of the steel embedded in the carbonated concrete was severely corroded. The degree of steel corrosion tended to increase with an increase in the amount of chloride ion as well as carbonation depth.","PeriodicalId":255305,"journal":{"name":"SP-179: Fourth CANMET/ACI/JCI Conference: Advances in Concrete Technology","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134593710","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