Effects of corrosion inhibiting admixtures and supplementary cementitious materials combinations on the strength and certain durability properties of HPC

2017 ◽  
Vol 44 (11) ◽  
pp. 918-926 ◽  
Author(s):  
H.Z. Lopez-Calvo ◽  
P. Montes-Garcia ◽  
E.M. Alonso-Guzmán ◽  
W. Martinez-Molina ◽  
T.W. Bremner ◽  
...  

This paper reports a study carried out to evaluate the effects of corrosion inhibiting admixtures, calcium nitrite and disodium tetrapropenyl succinate, in combination with supplementary cementitious materials, fly ash and silica fume Portland cement, on the compressive strength and certain durability properties of high performance concrete. Mixture formulations, including binary and ternary combinations of these admixtures were evaluated. Chloride profiles after 91 and 365 days of exposure and the compressive strength and electrical resistivity at 1, 7, 14, 28, 180, and 365 days of age were estimated. Also, results of corrosion evaluation after five-year exposure to a natural marine environment at Treat Island Maine, USA are presented and discussed. Results indicate that the use of corrosion inhibitors in combination with supplementary cementitious materials was beneficial, albeit to various degrees, in enhancing the strength and durability properties of high performance concrete with no noticeable adverse effects.

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1472
Author(s):  
Sungwoo Park ◽  
Siyu Wu ◽  
Zhichao Liu ◽  
Sukhoon Pyo

Although ultra high-performance concrete (UHPC) has great performance in strength and durability, it has a disadvantage in the environmental aspect; it contains a large amount of cement that is responsible for a high amount of CO2 emissions from UHPC. Supplementary cementitious materials (SCMs), industrial by-products or naturally occurring materials can help relieve the environmental burden by reducing the amount of cement in UHPC. This paper reviews the effect of SCMs on the properties of UHPC in the aspects of material properties and environmental impacts. It was found that various kinds of SCMs have been used in UHPC in the literature and they can be classified as slag, fly ash, limestone powder, metakaolin, and others. The effects of each SCM are discussed mainly on the early age compressive strength, the late age compressive strength, the workability, and the shrinkage of UHPC. It can be concluded that various forms of SCMs were successfully applied to UHPC possessing the material requirement of UHPC such as compressive strength. Finally, the analysis on the environmental impact of the UHPC mix designs with the SCMs is provided using embodied CO2 generated during the material production.


2021 ◽  
Vol 72 (1) ◽  
pp. 76-83
Author(s):  
Lam Le Hong ◽  
Lam Dao Duy ◽  
Huu Pham Duy

The demand for High Performance Concrete (HPC) is steadily increasing with massive developments. Conventionally, it is possible to use industrial products such as silica fume (SF), fly ash, as supplementary cementitious materials (SCM), to enhance the attributes of HPC. In recent years, nano-silica (NS) is used as an additive in added mainly to fill up the deviation arises with the addition of SF for HPC. This study aims to optimize the proportion of NS (produced in Vietnam) in the mixture used for fabricating 70 MPa high-performance concrete. SiO2 powder with particle size from 10 to 15 nm were used for mixing. A series of compressive strength test of HPC with nano-SiO2 varied from 0 to 2.8 percent of total of all binders (0%, 1.2%, 2%, 2.8%), and the fixed percentage of silica fume at 8% were proposed. Results show compressive strength increases with the increase of nano-SiO2, but this increase stops after reaching 2%. And at day 28 of the curing period, only concrete mixture containing of 8% silica fume and 2% nano-SiO2, had the highest compressive strength.


10.29007/81v5 ◽  
2018 ◽  
Author(s):  
Ashika Shah ◽  
Indrajit Patel ◽  
Jagruti Shah ◽  
Gaurav Gohil

In the production of Self Compacting concrete (SCC), the use of quaternary blend of supplementary cementitious materials (SCM’s) has not found enough applications. For this purpose, an effort has been done to present a mix design for M60 grade and M80 grade SCC with quaternary blending of fly ash(FA), ground granulated blast furnace slag (GGBS), silica fume (SF) in accordance with EFNARC guidelines. Findings: In this study, cement has been replaced with SCM’s from 30% to 50%. Fresh properties of concrete were tested for slump flow, T50 test and U box. The hardened properties of concrete were tested for compressive strength and durability. The tests were performed for 7, 28, 56 and 91 days. The results indicate that the use of quaternary blend has improved the workability, compressive strength and durability properties of specimens than the control specimen. Application: The primary contribution is to fill the congestedreinforcement and increase the durability and life span of the structure.


2020 ◽  
Vol 309 ◽  
pp. 26-30 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Tomáš Trtík ◽  
Roman Chylík ◽  
Vladimír Hrbek

The paper compares macromechanical and micromechanical properties of high-performance concrete containing supplementary cementitious materials and basalt aggregate. The aggregate was either a common unprocessed crushed basalt aggregate or crushed basalt aggregate the coarse fractions (4/8 and 8/16 mm) of which were washed by water and dried before use. The observed macro-mechanical properties were compressive strength, tensile strength, elastic modulus and depth of penetration of water under pressure; the paper is focused on the first observed property, which is the basic material characteristic. On the microscale, the thickness of the interfacial transition zone (ITZ) was determined by nanoindentation. The positive influence of supplementary cementitious materials and aggregate washing on compressive strength was confirmed and the correlation between macromechanical and micromechanical characteristics was proved.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Jisong Zhang ◽  
Yinghua Zhao ◽  
Haijiang Li

Ultra-high performance concrete (UHPC) has superior mechanical properties and durability to normal strength concrete. However, the high amount of cement, high environmental impact, and initial cost are regarded as disadvantages, restricting its wider application. Incorporation of supplementary cementitious materials (SCMs) in UHPC is an effective way to reduce the amount of cement needed while contributing to the sustainability and cost. This paper investigates the mechanical properties and microstructure of UHPC containing fly ash (FA) and silica fume (SF) with the aim of contributing to this issue. The results indicate that, on the basis of 30% FA replacement, the incorporation of 10% and 20% SF showed equivalent or higher mechanical properties compared to the reference samples. The microstructure and pore volume of the UHPCs were also examined. Furthermore, to minimise the experimental workload of future studies, a prediction model is developed to predict the compressive strength of the UHPC using artificial neural networks (ANNs). The results indicate that the developed ANN model has high accuracy and can be used for the prediction of the compressive strength of UHPC with these SCMs.


2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
E. H. Kadri ◽  
S. Aggoun ◽  
S. Kenai ◽  
A. Kaci

The compressive strength of silica fume concretes was investigated at low water-cementitious materials ratios with a naphthalene sulphonate superplasticizer. The results show that partial cement replacement up to 20% produce, higher compressive strengths than control concretes, nevertheless the strength gain is less than 15%. In this paper we propose a model to evaluate the compressive strength of silica fume concrete at any time. The model is related to the water-cementitious materials and silica-cement ratios. Taking into account the author's and other researchers’ experimental data, the accuracy of the proposed model is better than 5%.


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