Achieving high strength/high performance concrete from coral-limestone aggregates using ordinary Portland cement, fly ash and superplasticizer

Author(s):  
A Mrema ◽  
S Bungara
2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.


2015 ◽  
Vol 1129 ◽  
pp. 573-580 ◽  
Author(s):  
Walid Tahri ◽  
Z. Abdollahnejad ◽  
Jorge Mendes ◽  
F. Pacheco-Torgal ◽  
José Barroso de Aguiar

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.


2013 ◽  
Vol 639-640 ◽  
pp. 364-367 ◽  
Author(s):  
Xiao Bo Chen ◽  
Jian Yin ◽  
Wei Min Song

Based on engineering practice, autogenous volume deformation and creep properties of C60 high performance concrete(C60 HPC) and C60 high strength concrete(C60 HSC) were evaluated in the study. The results showed that the cement partly-replaced with fly ash could significantly decrease the creep deformation, creep coefficient and creep degree. In comparison with C60 HSC, the creep coefficient and creep degree of C60 HPC were decreased 17.9%and15.8% in 28 days, 22.9% and 21.0% in 270 days. For C60 HPC and C60 HSC at the same age, autogenous volume deformation of C60 HPC is greater than that of C60 HSC, but they were both less than 80×10-6 , and the autogenous volume deformation was basically completed in 7 days.


2018 ◽  
Vol 7 (2.1) ◽  
pp. 79 ◽  
Author(s):  
V Srinivasa Reddy ◽  
R Nirmala

In the last three decades, supplementary cementitious materials such as fly ash, silica fume and ground granulated blast furnace slag have been judiciously utilized as cement replacement materials as these can significantly enhance the strength and durability characteristics of concrete in comparison with ordinary Portland cement (OPC) alone. Hence, high-performance concretes can be produced at lower water/powder ratios by incorporating these supplementary materials. One of the main objectives of the present research work was to investigate synergistic action of binary, ternary and quaternary blended high strength grade (M80) concretes on its compressive strength. For blended high strength grade (M80) concrete mixes the optimum combinations are: Binary blend (95%OPC +5% FA, 95%OPC +5% MS and 95%OPC +5%MK), ternary blend (65%OPC+20%FA+15%MS) and quaternary blend (50%OPC+28%FA+11%MS+11%MK). Use of metakaolin in fly ash based blended concretes enhances compressive strength significantly and  found to be cost effective in terms of less cement usage, increased usage of fly ash and also plays a major role in early strength development  of fly ash based blended concrete.  


2001 ◽  
Vol 4 (2) ◽  
pp. 65-73 ◽  
Author(s):  
Ping-Kun Chang ◽  
Chao-Lung Hwang ◽  
Yaw-Nan Peng

The research and development of high-performance concrete (HPC) that can give both high flow characteristics and high strength have attracted wide interest in Taiwan. The construction of the 101-storey Taipei Financial Center and the 85-storey Tungtxt & Chingtai (T&C) Tower requires the slump to be in the range of 230 – 270 mm, the initial slump flow in the range of 580 – 620 mm and slump more than 230 mm after 45 minutes, as well as a 56-day compressive strength of over 56 MPa. The HPC mix is designed using a densified mixture design algorithm which aims to achieve the lowest cement content. With the addition of pozzolanic materials such as fly ash, the workability is much improved because the shape of fly ash is spherical. After one-year of strict quality control, the HPC achieve consistent workability and excellent strength. This indicates that the appropriate use of local industrial by-product materials can produce HPC of the required design strength.


2012 ◽  
Vol 204-208 ◽  
pp. 3695-3698
Author(s):  
Xiao Yan Guo ◽  
Run Xia Hao

High performance concrete was disposed under Portland cement dosage 270-310kg/m3 , fly ash blend percentage 40-50 and composite admixture. Workability of the concrete satisfy pumping requirement.28 day compression strength reach 31-44MPa, 90 day compression strength reach 40-56MPa.


2019 ◽  
Vol 296 ◽  
pp. 209-214 ◽  
Author(s):  
Jana Boháčová ◽  
Lukáš Janalík

The paper deals to create alkali activated composite based on the recipe of high-strength concrete. The paper includes the review of conditions for high-strength concrete proposing and preparation. Principles of design of high performance concrete based on Portland cement as a binder were described. The experiment was focused on the strength investigation of composites with different ratios of cement to slag, and also the effect of used activator on strength parameters was investigated.


2012 ◽  
Vol 446-449 ◽  
pp. 3544-3553
Author(s):  
Yun Fang Meng ◽  
Ya Yun Tan ◽  
Rui Li

The main purpose of this research was to enhance the strength and durability of concrete in both design and construction of high performance concrete. Particularly, the strength in high performance concrete is achieved by optimising the gangue, fly ash and silica fume replacement for cement. The gangue has been used as a cementitious material. Using data from tests on laboratory studies, comparisons are made of the properties and performance of the gangue, fly ash and silica fume concrete with conventional Portland cement concrete of similar and same mixture proportions. The many technical benefits available to high performance concrete user, such as reduced heat evolution, lower permeability and higher strength at later ages, at the same time, in order to increase resistance to sulphate attack and alkali silica reaction. A number of recommendations are given for the effective use of gangue and fly ash in high performance concrete. The results show that 10% gangue, 15% slag, 15% fly ash, 10% silica fume of replacement was found to be an optimum level and demonstrated excellent performance in strength. Literature review on the use of different supplementary cementitious materials in concrete to enhance strength was also reported. The paper is intended to provide guidance for those concerned with the design, application and performance of high properties concrete in practice where gangue and fly ash can also help to reduce costs and energy demands in the production of concrete compared with conventional Portland cement concrete.


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