Effect of curing on the compressive strength, resistance to chloride-ion penetration and porosity of concretes incorporating slag, fly ash or silica fume

1995 ◽  
Vol 17 (2) ◽  
pp. 125-133 ◽  
Author(s):  
A.A. Ramezanianpour ◽  
V.M. Malhotra
2011 ◽  
Vol 250-253 ◽  
pp. 307-312 ◽  
Author(s):  
Muthuramalingam Jayakumar ◽  
M. Salman Abdullahi

Even though the use of fly ash in concrete is nowadays a common practice, its relatively slow pozzolanic reactivity hinders its greater utilization; hence efficient methods of activation are on demand. This study was carried out to evaluate the influence of lime as a chemical activator on the mechanical and durability properties of high strength fly ash concrete. Mixtures were made with 0, 30, 40, and 50% of cement replaced by low calcium fly ash. Corresponding mixtures were also made with the same amount of fly ash and addition of 10% of lime to each mixture. For each concrete mixture, slump, compressive strength, water absorption, sorptivity, apparent volume of permeable voids, and resistance to chloride-ion penetration were measured. The results obtained showed that addition of lime improved the compressive strength significantly at all ages. The strength of all the fly ash mixtures containing lime surpassed that of the corresponding Portland cement mix at 60 days. Addition of lime also improved the sorptivity and resistance to chloride-ion penetration of the fly ash concrete. It however increases the water absorption and the volume of permeable voids of the fly ash concrete.


2011 ◽  
Vol 409 ◽  
pp. 249-254
Author(s):  
Prakash Parasivamurthy ◽  
Veena Jawali ◽  
Pramod Aralumallige Venkatakrisna

Concrete is the key material used in construction of various types, from flooring of a dwelling to multi-storied high rise structures, from pathways to an airport runways, from under ground tunnels and deep sea platforms to high-rise chimneys and towers. The greatest challenge in this millennium, especially in developing country like India, it needs to build concrete structures in quicker time, so as to meet high infrastructural demand. In order to achieve this, concrete construction practices will have to undergo a sea-change in the country. The study was focused on development of self-compacting concrete using high volume fly ash, admixed with quary dust and Silica fume. The objective of the study included evaluation of properties, viz. compressive strength, weight change observations in sulphate environment and resistance to chloride ion penetration. Several trial mixes were tested before optimizing the three Self-Compacting Concrete mixes based on binary and ternary blends. The strength variation of individual cubes in each of the mixes has been observed to be in the range of 28 to 46 MPa. Self-compacting concrete using high volume flyash, admixed with quary dust and Silica fume mixes have performed extremely well in aggressive chloride environments. Samples cured for 90 days and exposed to sulphate environment had reduced strengths compared to those cured in tap water, in all the blends. But the percentage reduction is lower in case of ternary blends as compared to control concrete. Keywords: Self-Compacting Concrete (SCC), Compressive Strength, High volume flyash, Quary dust, Silica fume, Supplementary Cementious Material (SCM).


Buildings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 146
Author(s):  
Jakub Hodul ◽  
Nikol Žižková ◽  
Ruben Paul Borg

Crystalline admixtures and industrial by-products can be used in cement-based materials in order to improve their mechanical properties. The research examined long-term curing and the exposure to environmental actions of polymer–cement mortars with crystalline admixture (CA) and different by-products, including Bengħisa fly ash and Globigerina limestone waste filler. The by-products were introduced as a percentage replacement of the cement. A crystallization additive was also added to the mixtures in order to monitor the improvement in durability properties. The mechanical properties of the mortar were assessed, with 20% replacement of cement with fly ash resulting in the highest compressive strength after 540 days. The performance was analyzed with respect to various properties including permeable porosity, capillary suction, rapid chloride ion penetration and chloride migration coefficient. It was noted that the addition of fly ash and crystalline admixture significantly reduced the chloride ion penetration into the structure of the polymer cement mortar, resulting in improved durability. A microstructure investigation was conducted on the samples through Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Crystals forming through the crystalline admixture in the porous structure of the material were clearly observed, contributing to the improved properties of the cement-based polymer mortar.


2012 ◽  
Vol 204-208 ◽  
pp. 3240-3243
Author(s):  
Hui Liu ◽  
Ping Li ◽  
Qiao Lan Jin

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.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wachilakorn Sanawung ◽  
Tieng Cheewaket ◽  
Weerachart Tangchirapat ◽  
Chai Jaturapitakkul

This research studies the effects of W/B ratios and palm oil fuel ash (POFA) on compressive strength, water permeability, and chloride resistance of concrete. POFA was ground until the particles retained on sieve number 325 were less than 5% by weight. POFA was used to partially replace OPC at rates of 15, 25, and 35% by weight of binder. The water to binder (W/B) ratios of concrete were 0.40 and 0.50. The compressive strength, water permeability, and chloride resistance of concrete were investigated up to 90 days. The results showed that POFA concrete with W/B ratio of 0.40 had the compressive strengths ranging from 45.8 to 55.9 MPa or 82–94% of OPC concrete at 90 days, while POFA concrete with W/B ratio of 0.50 had the compressive strengths of 33.9–41.9 MPa or 81–94% of OPC concrete. Furthermore, the compressive strength of concrete incorporation of ground POFA at 15% was the same as OPC concrete. The water permeability coefficient and the chloride ion penetration of POFA concrete were lower than OPC concrete when both types of concrete had the same compressive strengths. The findings also indicated that water permeability and chloride ion penetration of POFA concrete were significantly reduced compared to OPC concrete.


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