Research on the Problems and Countermeasures for Steam Curing of Assembled Composite Wallboard

2014 ◽  
Vol 580-583 ◽  
pp. 2299-2302
Author(s):  
Chun Yi Xu ◽  
Lei Yan ◽  
Chen Li ◽  
Zhi Wei Cao
Keyword(s):  
Field Test ◽  
Production Line ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Durability ◽  
Steam Curing ◽  
Volume Stability ◽  
Actual Production

For researching principle and production line state of steam curing of composite wallboard, the art have been conducted through actual investigation and field test. Based on the influence of steam curing on the strength of high performance concrete, durability and volume stability, put forward suggestions of steam curing system; Several problems have been raised for steam curing in the actual production, then some correlative improve measurements are given. Provide the reference for the production and development of the residential part in our country.

scholarly journals Investigation on Durability Performance in Early Aged High-Performance Concrete Containing GGBFS and FA

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Seung-Yup Jang ◽  
Subbiah Karthick ◽  
Seung-Jun Kwon
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Structural Safety ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Rc Structures

The significance of concrete durability increases since RC (Reinforced Concrete) structures undergo degradation due to aggressive environmental conditions, which affects structural safety and serviceability. Steel corrosion is the major cause for the unexpected failure of RC structures. The main cause for the corrosion initiation is the ingress of chloride ions prevailing in the environment. Hence quantitative evaluation of chloride diffusion becomes very important to obtain a chloride diffusion coefficient and resistance to chloride ion intrusion. In the present investigation, 15 mix proportions with 3 water-to-binder ratios (0.37, 0.42, and 0.47) and 3 replacement ratios (0, 30, and 50%) were prepared for HPC (high-performance concrete) with fly-ash and ground granulated blast furnace slag. Chloride diffusion coefficient was measured under nonstationary condition. In order to evaluate the microstructure characteristics, porosity through MIP was also measured. The results of compressive strength, chloride diffusion, and porosity are compared with electrical charges. This paper deals with the results of the concrete samples exposed for only 2 months, but it is a part of the total test plan for 100 years. From the work, time-dependent diffusion coefficients in HPC and the key parameters for durability design are proposed.

scholarly journals Effect of Graphene Oxide Nanosheets on Physical Properties of Ultra-High-Performance Concrete with High Volume Supplementary Cementitious Materials

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1929 ◽  
Author(s):  
Yu-You Wu ◽  
Jing Zhang ◽  
Changjiang Liu ◽  
Zhoulian Zheng ◽  
Paul Lambert
Keyword(s):  
Graphene Oxide ◽  
Physical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Steam Curing ◽  
Slump Flow

Nanomaterials have been increasingly employed for improving the mechanical properties and durability of ultra-high-performance concrete (UHPC) with high volume supplementary cementitious materials (SCMs). Recently, graphene oxide (GO) nanosheets have appeared as one of the most promising nanomaterials for enhancing the properties of cementitious composites. To date, a majority of studies have concentrated on cement pastes and mortars with fewer investigations on normal concrete, ultra-high strength concrete, and ultra-high-performance cement-based composites with a high volume of cement content. The studies of UHPC with high volume SCMs have not yet been widely investigated. This paper presents an experimental investigation into the mini slump flow and physical properties of such a UHPC containing GO nanosheets at additions from 0.00 to 0.05% by weight of cement and a water–cement ratio of 0.16. The study demonstrates that the mini slump flow gradually decreases with increasing GO nanosheet content. The results also confirm that the optimal content of GO nanosheets under standard curing and under steam curing is 0.02% and 0.04%, respectively, and the corresponding compressive and flexural strengths are significantly improved, establishing a fundamental step toward developing a cost-effective and environmentally friendly UHPC for more sustainable infrastructure.

Study on Volume Stability of High Strengthen High Performance Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 2977-2980
Author(s):  
Run Xia Hao ◽  
Xiao Yan Guo ◽  
Jun Mei Zhao
Keyword(s):  
Volume Change ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Normal Concrete ◽  
Cement Material ◽  
Volume Stability

Volume linearity change rule was found through contrast test of cement material net liquid of adding superfine slag power, high performance concrete and normal concrete. It is guidance significance for volume change of high strength and high performance concrete how to reduce.

Les effets des caractéristiques du réseau de bulles d'air, du type de mûrissement, du truellage de surface et de la fumée de silice sur la résistance à l'écaillage d'un béton à haute performance

1996 ◽  
Vol 23 (6) ◽  
pp. 1260-1271
Author(s):  
Richard Gagné ◽  
Yvon Latreille ◽  
Jacques Marchand
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Surface Finishing ◽  
Air Bubbles ◽  
Concrete Durability ◽  
Freeze Thaw ◽  
Spacing Factor ◽  
Entrained Air ◽  
Scaling Resistance

In Canada, high-performance concretes (HPCs) are increasingly used in construction and repair, particularly for its durability, which is distinctly superior compared with ordinary concrete. The current tendency is to provide for a spacing factor of air bubbles lower than 230 μm in all HPCs that are subjected to freeze–thaw cycles. This choice is basically the outcome of an ongoing controversy as to the necessity of providing a good network of entrained air bubbles to protect HPCs against freeze–thaw cycles. In the future, the optimal use of HPC will depend, among other factors, on a better understanding of minimal requirements regarding the characteristics of air voids to ensure a good behavior of HPCs under freeze–thaw cycles. The results of the investigation reported herein show that a spacing factor lower than approximately 500 μm can be sufficient to ensure a good resistance of HPCs to scaling. It is also shown that surface trawling, slump, and set-retarding agents have only secondary effects on the scaling resistance of HPCs. Silica fume and membrane curing have allowed to improve significantly the scaling resistance of the HPCs under investigation. Key words: high-performance concrete, durability, scaling, set-retarding agent, silica fume, surface finishing, curing, pumping, entrained air, spacing factor.

Influence of Slag Fineness on Durability of High-Performance Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 3240-3243
Author(s):  
Hui Liu ◽  
Ping Li ◽  
Qiao Lan Jin
Keyword(s):  
Compressive Strength ◽  
Surface Area ◽  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Concrete Durability ◽  
Chloride Ion Penetration ◽  
Ion Penetration

This research focuses on investigating the high performance concrete durability containing slag with different fineness and dosage. For this purpose, the 28-day compressive strength, chloride ion penetration, and frost resistance were investigated, with slag surface area 420m2/kg, 530m2/kg, 610m2/kg, and 720m2/kg, and replacement percentage 0%, 20%, 40%, and 60%, respectively. It was found that chloride ion penetration resistance were affected by the fineness and dosage of slag, and concrete frost resistance property was mainly controlled by dosage of slag rather than the fineness, and the 28-day compressive strength increased with slag incorporation.

scholarly journals Performance of a Fly Ash Geopolymeric Mortar for Coating of Ordinary Portland Cement Concrete Exposed to Harsh Chemical Environments

2015 ◽  
Vol 1129 ◽  
pp. 573-580 ◽  
Author(s):  
Walid Tahri ◽  
Z. Abdollahnejad ◽  
Jorge Mendes ◽  
F. Pacheco-Torgal ◽  
José Barroso de Aguiar
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Epoxy Resin ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Surface Treatments ◽  
Concrete Durability ◽  
Portland Cement Concrete ◽  
Chemical Attack

Premature degradation of ordinary Portland cement (OPC) concrete infrastructures is a current and serious problem with overwhelming costs amounting to several trillion dollars. The use of concrete surface treatments with waterproofing materials to prevent the access of aggressive substances is an important way of enhancing concrete durability. The most common surface treatments use polymeric resins based on epoxy, silicone (siloxane), acrylics, polyurethanes or polymethacrylate. However, epoxy resins have low resistance to ultraviolet radiation while polyurethanes are sensitive to high alkalinity environments. Geopolymers constitute a group of materials with high resistance to chemical attack that could also be used for coating of concrete infrastructures exposed to harsh chemical environments.This article presents results of an experimental investigation on the resistance to chemical attack (by sulfuric and nitric acid) of several materials: OPC concrete, high performance concrete (HPC), epoxy resin, acrylic painting and a fly ash based geopolymeric mortar. Two types of acids, each with high concentrations of 10%, 20% and 30%, were used to simulate long term degradation by chemical attack. The results show that the epoxy resin had the best resistance to chemical attack, irrespective of the acid type and acid concentration.

Research Status and Prospects on the Ultra High Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1506-1508
Author(s):  
Jie Sun
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
The Sustainable Development ◽  
Volume Stability ◽  
Existing Problems ◽  
Practical Engineering

The ultra high performance concrete is a new cement-based composite material with ultra-high mechanical properties, excellent durability and excellent volume stability. In this paper, research and application of the ultra high performance concrete at home and abroad at present was introduced, existing problems of the ultra high performance concrete applied to much practical engineering were pointed out. Finally, the prospects of ultra high performance concrete were analyzed and the ultra high performance concrete is inevitable result of the sustainable development of modern concrete technology.

Influence of CaO-Based Expansive Agent on the Deformation Behavior of High Performance Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 113-116
Author(s):  
Shou Zhi Zhang ◽  
Qian Tian ◽  
An Qun Lu
Keyword(s):  
Deformation Behavior ◽  
High Performance ◽  
High Performance Concrete ◽  
Control Volume ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Volume Stability ◽  
Expansive Agent ◽  
Effective Expansion ◽  
New Type

In order to improve the volume stability of high performance concrete, the effects of deformation behavior of high performance concrete containing CaO-based expansive agent were investigated. Concrete samples prepared without or with CaO-based expansive agent were compared through expansion under water curing at 20°C, drying shrinkage and autogenous shrinkage measurements. According to the experimental and analytical results, the new type expansive agent can control volume stability for high performance concrete. The addition of 10% CaO-based expansive agent not only built effective expansion in high performance concrete whatever under saturated condition or under sealed condition, but also substantially reduced its drying shrinkage.

Numerical analyses on flexural performance of prefabricated UHPC link slab

2021 ◽  
Author(s):  
Bruno Briseghella ◽  
Wei Xu ◽  
Jun-Qing Xue ◽  
Jian-hui Lin ◽  
Camillo Nuti
Keyword(s):  
Crack Resistance ◽  
Bearing Capacity ◽  
High Performance ◽  
High Performance Concrete ◽  
Labor Cost ◽  
Ultimate Bearing Capacity ◽  
Ultra High Performance Concrete ◽  
Steam Curing ◽  
Expansion Joints

<p><br clear="none"/></p><p>The expansion joints in the multi-span simply supported bridge can be eliminated by using the link slab. The ultra-high performance concrete (UHPC) with high tensile strength and crack resistance is an effective material for the link slab. However, the cast-in-situ UHPC link slab need to be cured with steam curing. Therefore, the construction processes are complicated and the construction quality is difficult to guarantee. In this paper, the prefabricated UHPC link slab which can be assembled on site to simply the construction process, accelerate the construction speed and reduce the labor cost was proposed. Finite element models of the prefabricated and cast-in-situ UHPC link slabs under bending were built by using ABAQUS. The ultimate bearing capacity of the prefabricated link slab was nearly the same of the cast in situ and the crack resistance slightly lower. Finally, the influence of the bolt (used to connect the prefabricated link slab) number and the distance from the bolt to the edge of the link slab on the crack resistance and ultimate bearing capacity of the prefabricated link slab were obtained.</p>

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