Life Cycle CO2 Emission Assessment for Non-Steam Curing Precast Concrete

2014 ◽  
Vol 1025-1026 ◽  
pp. 539-542
Author(s):  
Taeh Young Kim ◽  
Sung Ho Tae ◽  
Keun Hyeok Yang

Researches on development of technology to reduce CO2 emission while satisfying physical properties during production of precast concrete, which is mainly applied to building structures, are necessary. Accordingly, a high early strength type mixture for which removal of precast concrete form can be done by curing at room temperature instead of steam curing in the production process of precast concrete was developed. The developed high early strength type mixture was mixed with concrete to conduct coagulation, slump, and compressive strength property tests. In addition, CO2 emission and reduction performance of non-steam curing precast concrete were assessed.

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.


2017 ◽  
Vol 744 ◽  
pp. 105-113 ◽  
Author(s):  
Takayoshi Maruyama ◽  
Hideaki Karasawa ◽  
Shigeyuki Date

Pre-cast concrete products are sometimes manufactured in two cycles daily. It is ensured that they have the required strength at an early stage of demolding by increasing the steam curing temperature to reduce cost or increase productivity. However, the reduction in durability because of cracking due to thermal stress is a topic of concern. On the other hand, it has been known that fine blast-furnace-slag powder and expansive agents show high temperature dependence. Although they are used even in precast concrete products, the effect of steam curing on these materials is not known. Thus, in this study, the expression of compressive strength and expansion that are critical in improving the quality and productivity of precast concrete products was investigated, using high early-strength cement and two types of expansive agents, namely, ettringite-based and lime-based agents. Consequently, the strength expression was accelerated by the addition of expansive agent to ordinary cement and high early-strength cement. The extent of restrained expansion is greater for the lime-based expansive agent than for the ettringite-based expansive agent, and when an expansive agent is added to high early-strength cement, the extent of restrained expansion falls to a level lower than that in the case of ordinary cement.


2019 ◽  
Vol 278 ◽  
pp. 01005
Author(s):  
Erica Enzaki ◽  
Takashi Sakuma ◽  
Eizou Takeshita ◽  
Shigeyuki Date

In recent years, the use of blast furnace slag material is being focused as environmental loading reduction and sustainable construction. However, in general, autogeneours shrinkage of the concrete using much amount of GGBFS is large in compared to normal concrete, therefore risk of cracking should be cared. On the other hand, strength development speed of concrete at early stage will be decreasing as the dosage of GGBFS increases, even under steam curing condition. It can be considered these points will be significant disadvantage in both productivity and quality of precast concrete. So in this study, early strength type expansive agent and setting accelerator were used in combination. As a result, it was confirmed that compressive strength at early stage is obviously increased. And steam curing temperature can be reduced about 10 degrees, and also, 600×10-6 of restraint expansion was obtained.


2016 ◽  
Vol 678 ◽  
pp. 1-13 ◽  
Author(s):  
Jun Kono ◽  
Yutaka Goto ◽  
York Ostermeyer ◽  
Rolf Frischknecht ◽  
Holger Wallbaum

Thermal insulation material is an important component to reduce the environmental impact of buildings through the reduction of energy consumption in the operation phase. However, the material itself has embodied environmental impacts for the value it provides. Eco-efficiency is a method that quantifies relation between the environmental performance and the created value of a product system. This study investigated contributing factors of the eco-efficiency of thermal insulation materials to support decision making of material manufacturers. For the improvement of eco-efficiency, the assessment was made in two scopes: investigating the contributing factors of impact caused at production processes; and thermal performance through thermo-physical properties. For quantifying environmental impacts, cradle-to-grave life cycle assessment (LCA) of each materials were made. The life cycle impact assessment (LCIA) indicators used were ReCiPe H/A and global warming potential (GWP100a). For the assessment of production process, the inventories of the materials were assigned to six categories: heat, chemicals, electricity, transportation, raw materials and wastes. Among the assessed materials, contribution of electricity and heat within the production process was large for foam glass which had the highest potential to improve the eco-efficiency which was by factor 1.72. The analysis on relation between thermo-physical properties and eco-efficiency based on product data of the materials highlighted the importance of density as an indicator upon development and use. Althoughdensity often gains less attention,the finding suggested the effectiveness of improving the efficiency by having lower density without compensating the performance of the materials.


Alloy Digest ◽  
1953 ◽  
Vol 2 (8) ◽  

Abstract ELEKTRON ZRE1 is a magnesium-base casting alloy which combines excellent creep resistance up to about 500 F with good room temperature properties. It is completely free from microporosity and very suitable for applications requiring pressure tightness. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: Mg-6. Producer or source: Aluminum Laboratories Ltd.


Alloy Digest ◽  
2010 ◽  
Vol 59 (2) ◽  

Abstract Ancorsteel 1000 is the workhorse of the Ancorsteel series. It has low levels of carbon and oxygen and good compressibility. In the powder production process used to make Ancorsteel, molten steel is atomized into irregular, homogeneous particles that are then annealed to produce uniform, dependable steel powders. This datasheet provides information on composition, physical properties, and compressive strength. It also includes information on powder metal forms. Filing Code: CS-152. Producer or source: Hoeganaes Corporation.


2011 ◽  
Vol 194-196 ◽  
pp. 1085-1088
Author(s):  
Zhi Min He ◽  
Xiao Ju Shen ◽  
Jun Zhe Liu

The use of fly ashes for cement-replacement purposes, especially in high volumes, decreases rate of early strength development of the steam curing concrete. To resolve it, this paper developed a new steam-cured concrete incorporating fly ash and a chemical activator (gypsum). Experiments were conducted to investigate the mechanical properties at early and later ages of steam and standard curing concretes. The corresponding mechanism was also discussed by testing the microstructure of concretes. Results indicate that the demoulding compressive strength of steam curing concrete with 4% gypsum dosage can meet production requirements, and compressive strength of this concrete at later ages increase well. Compared with that of ordinary pure cement steam-cured concrete, concrete with 4% gypsum has a higher compressive strength gain rate. At an early age, addition of the gypsum can distinctly accelerate the extent of hydration of the steam curing fly ash cement systems, and thus the microstructure of concrete becomes denser. However, in standard curing condtion, the effect of gypsum is not distinct.


2013 ◽  
Vol 9 (2) ◽  
Author(s):  
Erwin Rommel

The use of concrete as a building material has been developed both in quantity and qualityaspects. Concrete production time is long term in a foundry to make many breakthroughs to makea concrete material that fast food, such as precast concrete. The use of precast concrete in the areaof an aggressive environment than expected strength factors are also needed high durability,including resistance to porosity and permeability properties of concrete.This research was conducted with the cooperation of one of Precast Concrete Factory in EastJava, including the manufacture of 15x15x15 cm cube of concrete and steam curing system.Thisvariable on research ; use the type of cement (pozzolan cement and cement type-1), the length ofsteam (5 and 7 hours), and the quality concrete (K350 and K700). As for the testing performed oncompressive strength, permeability and porosity of concrete.This study concluded that steam curing system to provide early strength concrete that isbetter than conventional curing (non-steam), where compressive strength of the post-steam canreach 51% of high-strength concrete (K700) with the results 361 kg/cm2, whereas in normalconcrete (K350) reached 52% (compressive strength 192 kg/cm2). Pozzolan cement concrete alsohas the advantage in increasing the durability of concrete, especially in high-strength concrete,where the concrete porosity becomes smaller either by steam curing and non-steam. Permeabilityof concrete is given a steam becomes smaller than the normal concrete with conventional curing(non-steam).Key word : steam curing, pozzolan cement, strength of concrete


1978 ◽  
Vol 57 (4) ◽  
pp. 593-596 ◽  
Author(s):  
Rodney Tuenge ◽  
Ivens A. Siegel ◽  
Kenneth T. Izutsu

The physical properties of a zinc phosphate cement prepared on a room temperature slab were compared to those of the cement prepared on a frozen slab. Solubility, compressive strength, and setting time of cements prepared on both types of slabs were within the limits set by A.D.A. Specification No. 8.


2020 ◽  
Vol 302 ◽  
pp. 101-106
Author(s):  
Siriphorn Rabma ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The aim of this research was to study the properties of cement reinforced with coconut fiber. The coconut fiber addition that uses in this research were 5, 10 and 15% by weight of cement. The cement paste and coconut fiber were mixed together and packed into an iron mold. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the water bath at 3, 7 and 28 days. After that, the physical properties i.e. water absorption and density were examined. The microstructure was characterized by scanning electron microscopy (SEM). The results showed the surfaces of the coconut fibers were not smooth, spread with nodes and irregular stripes, which is covered with substances and other impurities. The compressive strength and flexural strength were also investigated. From the results, the mechanical properties were decreased with increasing coconut fiber content due to reducing density and higher porosity and water absorption compared to non-fiber cement paste and physical properties of fiber had been flexibility and smoother caused poor binding with cement. The best compressive strength and flexural strength results were obtained with the percentages of coconut fiber as 5% which value as 26.67 N/mm2 and 5.08 N/mm2 respectively.


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