scholarly journals Ecological and technological effects of using concretes with low Portland clinker

2020 ◽  
Vol 322 ◽  
pp. 01021
Author(s):  
Mikołaj Ostrowski ◽  
Paweł Pichniarczyk ◽  
Grzegorz Kądzielawski
Keyword(s):  
Mechanical Properties ◽  
Ecological Effects ◽  
Hardened Concrete ◽  
Test Results ◽  
Concrete Technology ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mix ◽  
New Generation ◽  
Mineral Additives ◽  
Furnace Slag

Concrete with a low Portland clinker content involves the use of mineral additives as a cement component or as a additive in a concrete mix. The main factors influencing the increasing use of mineral additives in concrete technology are the advantageous development of the functional properties of the concrete mix, hardened concrete and a large impact on the ecological effects, including reduction of CO2 emissions. The use of concrete with a low Portland clinker content is part of the strategy for sustainable development of the economy. This paper describes the technological and ecological effects of using silica fly ash and granulated blast furnace slag additives in concretes with a low Portland clinker content. The cement and concrete additives used were mechanically activated, which allowed to reduce the content of Portland clinker in concrete. A new generation superplasticizer was used in the research, enabling a low water-cement ratio to be obtained. The mechanical properties and ecological effects of the production and use of concretes with a low content of Portland clinker were determined, including the reduction of CO2 emissions. Test results confirmed the very good mechanical properties of concrete with a high content of mechanically activated mineral additives. The research also showed an average of 3 times lower CO2 emissions compared to reference concretes made of CEM I Portland cement without additives.

scholarly journals Flexural Behaviour of Reinforced Rapid Hardened Concrete Beams

2020 ◽  
Vol 9 (3) ◽  
pp. 2281-2286
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Ductile Failure ◽  
Flexural Behavior ◽  
Hardened Concrete ◽  
Test Results ◽  
Flexural Behaviour ◽  
Concrete Technology ◽  
Construction Time ◽  
Compressive Strength Of Concrete

In the last decades concrete technology has made it easier to reach early strength, Rapid Hardened Concrete is one of the construction concretes used widely. The use of rapid hardened concrete is increased due to the possibility to limit the construction time. The purpose of this paper is to investigate the mechanical properties of Rapid Hardened Concrete (RHC). Properties studied include compressive strength, tensile strength, and flexural behavior. Mechanical properties were evaluated based on the compressive, tensile, and bend test results for both normal and rapid hardened concrete. The effect of admixture percentages (Sikament-nn) on hardening properties of rapid concrete was studied. The experimental investigation indicated that the flexural and compressive strength of concrete increased with the addition of Sikament-nn at the age of 1, 3, 7, and 28 days and the optimal percentage of Sikament-nn was 2%. In addition, test results show that rapid hardened concrete exhibit ductile failure and significant displacement before failure. The ultimate displacement of rapid hardened concrete was an increase more 50% than control RC beams.

scholarly journals Mechanical Characteristics of Hardened Concrete with Different Mineral Admixtures: A Review

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Tehmina Ayub ◽  
Sadaqat Ullah Khan ◽  
Fareed Ahmed Memon
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Drying Shrinkage ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Granulated Blast Furnace Slag ◽  
Shrinkage And Creep ◽  
Furnace Slag

The available literature identifies that the addition of mineral admixture as partial replacement of cement improves the microstructure of the concrete (i.e., porosity and pore size distribution) as well as increasing the mechanical characteristics such as drying shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity; however, no single document is available in which review and comparison of the influence of the addition of these mineral admixtures on the mechanical characteristics of the hardened pozzolanic concretes are presented. In this paper, based on the reported results in the literature, mechanical characteristics of hardened concrete partially containing mineral admixtures including fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA) are discussed and it is concluded that the content and particle size of mineral admixture are the parameters which significantly influence the mechanical properties of concrete. All mineral admixtures enhance the mechanical properties of concrete except FA and GGBS which do not show a significant effect on the strength of concrete at 28 days; however, gain in strength at later ages is considerable. Moreover, the comparison of the mechanical characteristics of different pozzolanic concretes suggests that RHA and SF are competitive.

scholarly journals Performance and Behaviour of Ground Granulated Blast Furnace Slag Imparted to Geopolymer Concrete Structural Elements and Analyzed with ANSYS

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Maria Rajesh Antonyamaladhas ◽  
Selvamony Chachithanantham ◽  
Anandakumar Ramaswamy
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Weight Ratio ◽  
Hardened Concrete ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Structural Elements ◽  
Granulated Blast Furnace Slag ◽  
Mix Proportion ◽  
Furnace Slag

This paper deals with the behaviour of geopolymer concrete using ground granulated blast furnace slag and steel fibre to compare with M40 grade cement concrete. The cast GPC specimens were placed in a hot curing chamber at 60∘C temperature for 24 hours and tested after 1, 7, 14, and 28 days of ambient curing to find the strength and durability of hardened concrete. The optimum value of compressive strength was attained at 12 Molarities. Fly ash was replaced by GGBS in GPC with different proportions such as 0% to 60% at 5% interval; the optimum strength value was obtained on 40% replacement. From the test results, the compressive, split-tensile, and flexural strength of GPC specimens were 20%, 43%, and 53% higher than those of the control specimens. Based on the optimum strength mix proportion, the structural elements were cast to investigate the stress-strain relations. The GPC beam and L-section showed 33% and 16% higher value. From the results of acid and sulphate resistance tests, it was found that the strength and weight ratio of GPC were higher than the control specimens. From the simulations, it was found that the experimental test results were approximately equal to the ANSYS.

scholarly journals Effect of fine recycled aggregates on the properties of non-cement blended materials

2020 ◽  
Vol 323 ◽  
pp. 01018
Author(s):  
Wei-Ting Lin ◽  
Lukáš Fiala ◽  
An Cheng ◽  
Michaela Petříková
Keyword(s):  
Compressive Strength ◽  
Blast Furnace Slag ◽  
Interface Structure ◽  
Strength Test ◽  
Recycled Aggregates ◽  
Test Results ◽  
Granulated Blast Furnace Slag ◽  
Fine Aggregates ◽  
Compressive Strength Test ◽  
Furnace Slag

In this study, the different proportions of co-fired fly ash and ground granulated blast-furnace slag were used to fully replace the cement as non-cement blended materials in a fixed water-cement ratio. The recycled fine aggregates were replaced with natural fine aggregates as 10%, 20%, 30%, 40% and 50%. The flowability, compressive strength, water absorption and scanning electron microscope observations were used as the engineered indices by adding different proportions of recycled fine aggregates. The test results indicated that the fluidity cannot be measured normally due to the increase in the proportion of recycled fine aggregates due to its higher absorbability. In the compressive strength test, the compressive strength decreased accordingly as the recycled fine aggregates increased due to the interface structure and the performance of recycled aggregates. The fine aggregates and other blended materials had poor cementation properties, resulting in a tendency for their compressive strength to decrease. However, the compressive strength can be controlled above 35 MPa of the green non-cement blended materials containing 20% recycled aggregates.

scholarly journals MICRO-MECHANICAL PROPERTIES OF CEMENT AND SLAG COMPOSITES MEASURED BY NANOINDENTATION

2020 ◽  
Vol 26 ◽  
pp. 45-49
Author(s):  
Jiří Němeček ◽  
Jiří Němeček
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Modulus Of Elasticity ◽  
Volume Fraction ◽  
Blended Cement ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
The Difference ◽  
Portland Cement Paste ◽  
Furnace Slag

In this study, the micromechanical response of two cementitious composites was characterized by nanoindentation. Pure Portland cement paste and Portland cement with 50 vol. % replaced with granulated blast furnace slag (GBFS) paste were investigated at the age of 28 days. Grid nanoindentation, statistical deconvolution and scanning electron microscopy were used to characterize the main hydration products. Several grids with approximately 500 indents on each sample were performed to obtain modulus of elasticity, hardness and creep indentation parameter. Similar mechanical phases containing calcium silica hydrate, crystalline calcium hydroxide and un-hydrated clinker were found in both samples varying by volume fraction. Blended cement, moreover, contains a phase of slag hydration products with a significantly lower modulus of elasticity. This phase with a high portion of unreacted GBFS is mostly responsible for the difference of mechanical properties of the whole composite.

scholarly journals Fine ground granulated blast furnace slag for saving quantity of binder

2019 ◽  
Vol 110 ◽  
pp. 01055
Author(s):  
Liliya Kazanskaya ◽  
Nicolay Privalov ◽  
Svetlana Privalova
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Mineralogical Composition ◽  
High Specific Surface Area ◽  
Resource Saving ◽  
Water Reduction ◽  
Granulated Blast Furnace Slag ◽  
Mineral Additives ◽  
Furnace Slag

Nowadays, it is acknowledged that the use of mineral additives based on ground slag is one of ways of resource saving and improvement of technical properties of cement composites. Mineral additives with fineness similar to the Portland cement fineness are often used to replace part of Portland cement. Two kinds of ultra-fine ground granulated blast furnace slag that differ in composition and fineness were studied in the paper. Water-reduction due to effect of super plasticizer in slag-Portland cement compositions with amount of slag up to 70% was studied. The results of reduction of binder quantity per 1 kg of chemical admixture due to significant water-reduction are obtained and analysed. Correlations depending on kind, amount and fineness of slags, as well as depending on mineralogical composition of Portland cement were stated. The ultra-fine mineral additives based on ground slag with high specific surface area can be used for significant reduction of compositional binder.

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