scholarly journals Influence of formwork liners on fresh, mechanical and durability properties of cast concretes

2021 ◽  
Author(s):  
Sunny R Gurbani
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Surface Characteristics ◽  
Concrete Surface ◽  
Chloride Penetration ◽  
Freeze Thaw ◽  
Durability Properties ◽  
Salt Scaling ◽  
Chloride Penetration Resistance ◽  
Scaling Resistance

The following study investigates the influence of formwork liners on fresh, mechanical and durability properties of cast concretes. In order to investigate the influence of formwork liners (Weather Shield, Poligloss and Zemdrain) manufactured by Newark Group on concrete properties, column and other specimens were cast in conventional moulds (steel, wood and plastic) with and without formwork liners. As per ASTM Standards Surface characteristics, compressive strength, water absorption, sorptivity, chloride penetration, freeze thaw and salt scaling tests were conducted and results are analyzed. It is found that by the application of formwork liners Zemdrain and Weather Shield, compressive strength, water absorption, sorptivity, chloride penetration resistance, freeze thaw resistance and salt scaling resistance were improved. By the application of Poligloss, concrete surface was found to be homogenous without any visible blow-holes.

scholarly journals Influence of formwork liners on fresh, mechanical and durability properties of cast concretes

2021 ◽  
Author(s):  
Sunny R Gurbani
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Surface Characteristics ◽  
Concrete Surface ◽  
Chloride Penetration ◽  
Freeze Thaw ◽  
Durability Properties ◽  
Salt Scaling ◽  
Chloride Penetration Resistance ◽  
Scaling Resistance

The following study investigates the influence of formwork liners on fresh, mechanical and durability properties of cast concretes. In order to investigate the influence of formwork liners (Weather Shield, Poligloss and Zemdrain) manufactured by Newark Group on concrete properties, column and other specimens were cast in conventional moulds (steel, wood and plastic) with and without formwork liners. As per ASTM Standards Surface characteristics, compressive strength, water absorption, sorptivity, chloride penetration, freeze thaw and salt scaling tests were conducted and results are analyzed. It is found that by the application of formwork liners Zemdrain and Weather Shield, compressive strength, water absorption, sorptivity, chloride penetration resistance, freeze thaw resistance and salt scaling resistance were improved. By the application of Poligloss, concrete surface was found to be homogenous without any visible blow-holes.

scholarly journals CHLORIDE PENETRATION RESISTANCE OF CONCRETE SEALER AND COATING SYSTEMS

2015 ◽  
Vol 21 (4) ◽  
pp. 492-502 ◽  
Author(s):  
Khaled A. Soudki ◽  
Md. Safiuddin ◽  
Paul Jeffs ◽  
Gary Macdonald ◽  
Marcos Kroker
Keyword(s):  
Concrete Surface ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Water Soluble ◽  
Test Results ◽  
Nacl Solution ◽  
Total Water ◽  
Freeze Thaw ◽  
Powder Samples ◽  
Chloride Penetration Resistance

This study investigated the chloride penetration resistance of a silane-based sealer (SS1), an acrylic-based coating (AC1), and two cementitious coatings (CC1 and CC2) when applied on concrete surface. Concrete powder samples were collected from 15, 30 and 45 mm depths of sealer and coating treated concrete prism specimens, which were exposed to H2O and de-icing solutions of NaCl, Geomelt S30, MgCl2 and CaCl2 for 100 freeze-thaw cycles followed by 25 wet-dry cycles. Chloride analysis was carried out to determine the total water-soluble chlorides of concrete. Test results revealed that the chloride penetration for exposure to the de-icing chemicals occurred at a depth of 15 mm from the concrete surface. The highest chloride penetration occurred for the non-treated concrete. The sealer ‘SS1’ exhibited good performance except with exposure to NaCl solution. Among the three different coating products, the acrylic-based coating ‘AC1’ was the best-performing coating, whereas the cementitious coating ‘CC1’ had the worst performance. The amount of penetrated water-soluble chlorides was greater than the maximum recommended value of 0.025% (by concrete weight) at 15 mm depth for the sealer ‘SS1’ when exposed to NaCl de-icing solution, and for the coating ‘CC1’ when exposed to NaCl, CaCl2 and MgCl2 solutions.

scholarly journals Effects of Anti-Graffiti Protection on Concrete Durability

2014 ◽  
Vol 634 ◽  
pp. 517-526 ◽  
Author(s):  
Elsa Neto ◽  
Ana Souto ◽  
Aires Camões ◽  
Arlindo Begonha ◽  
Paulo Cachim
Keyword(s):  
Water Absorption ◽  
Atmospheric Pressure ◽  
Surface Characteristics ◽  
Concrete Surface ◽  
Experimental Program ◽  
Concrete Durability ◽  
Protection Systems ◽  
Before And After ◽  
Paint Removal ◽  
Durability Of Concrete

The heritage of fair-faced concrete, largely built in the twentieth century and nowadays recognized as heritage to be protected, is susceptible to attacks by graffiti, a form of vandalism that causes a major social and economic impact on society. Concrete is a porous material sometimes deteriorated over the years, and the interactions between the inks and the substrate and removal methods sometimes deteriorate or alter the concrete surface, especially if it is necessary to repeat the removal process. The anti-graffiti products are applied on the surface of the concrete, hindering the adhesion of paints or preventing its penetration into the pores of concrete, which in turn facilitates their removal. However, it appears that many of the existing protective products on the market may also alter the surface characteristics of the concrete irreversibly. Considering that the durability of concrete depends on the composition and characteristics of the surface, it is essential to know the effects of anti-graffiti protection systems on the durability of concrete and adopt the appropriate methodology to preserve this heritage. Thus, an experimental program was developed for analyzing changes in durability indicators and surface properties that protect concrete from deterioration (i) concrete without protection before and after application of spray paint, (ii) concrete with protection before and after application of spray paint and (iii) after paint removal were studied. Two anti-graffiti products were evaluated: a permanent and a sacrificial one. Effects of the anti-graffiti systems on the concrete durability are investigated and the tests performed include: water absorption by capillary and immersion at atmospheric pressure. The results of the water absorption tests show that the graffiti protection reduces the water absorption into the concrete and facilitates the removal of the graffiti without affecting negatively the characteristics of the surface and thus contributing to improve its durability.

Fresh, Durability and Mechanical Behavior of Self Consolidating Concrete Incorporating Fly Ash and Admixture under Hot Weather

2021 ◽  
Vol 904 ◽  
pp. 453-457
Author(s):  
Samer Al Martini ◽  
Reem Sabouni ◽  
Abdel Rahman Magdy El-Sheikh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Weather Conditions ◽  
Chloride Penetration ◽  
The Self ◽  
Fresh Properties ◽  
Self Consolidating Concrete ◽  
Slump Flow ◽  
Hot Weather

The self-consolidating concrete (SCC) become the material of choice by concrete industry due to its superior properties. However, these properties need to be verified under hot weather conditions. The paper investigates the behavior of SCC under hot weather. Six SCC mixtures were prepared under high temperatures. The SCC mixtures incorporated polycarboxylate admixture at different dosages and prolonged mixed for up to 2 hours at 30 °C and 40 °C. The cement paste was replaced with 20% of fly ash (FA). The fresh properties were investigated using slump flow, T50, and VSI tests. The compressive strength was measured at 3, 7, and 28 days. The durability of SCC mixtures was evaluated by conducting rapid chloride penetration and water absorption tests.

Influence of Fly Ash and Basalt Fibers on Strength and Chloride Penetration Resistance of Self-Consolidating Concrete

2016 ◽  
Vol 866 ◽  
pp. 3-8 ◽  
Author(s):  
Osama Ahmed Mohamed ◽  
Waddah Al Hawat
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Strength Properties ◽  
Chloride Penetration ◽  
Partial Replacement ◽  
Basalt Fibers ◽  
Self Consolidating Concrete ◽  
Chloride Penetration Resistance ◽  
Hardened Properties

Fly ash is a sustainable partial replacement of Portland cement that offers significant advantages in terms of fresh and hardened properties of concrete. This paper presents the findings of a study that aims at assessing the durability and strength properties of sustainable self-consolidating concrete (SCC) mixes in which Portland cement was partially replaced with 10%, 20%, 30%, and 40% fly ash. The study confirms that replacing Portland cement with fly ash at all of the percentages studied improves resistance of concrete to chloride penetration. The 40% fly ash mix exhibited the highest resistance to chloride penetration compared to the control mix. Despite the relative drop in compressive strength after 7 days of curing, the 28-day compressive strength of 40% SCC mix reached 55.75 MP, which is very close to the control mix. The study also confirms that adding 1%, 1.5%, and 2% basalt fibers, respectively, to the 40% fly ash mix improves the resistance to chloride penetration compared to the mix without basalt fibers.

scholarly journals PROPERTIES OF CEMENT-FLY ASH MIXTURES WITH SUBSTANDARD FLY ASH AS A PARTIAL CEMENT AND FINE AGGREGATE REPLACEMENT

2021 ◽  
Vol 11 (3) ◽  
pp. 71-88
Author(s):  
Piseth Pok ◽  
Parnthep Julnipitawong ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Sulfate ◽  
Chloride Penetration ◽  
The Other ◽  
Fine Aggregate ◽  
Carbonation Depth ◽  
Cement Replacement ◽  
Durability Properties ◽  
Compressive Strength Of Concrete

This research investigated the effects of using a substandard fly ash as a partial cement and/or fine aggregate replacement on the basic and durability properties of cement-fly mixtures. Experimental results showed that utilizing the substandard fly ash led to increase in water requirement and autoclave expansion of pastes. The strength activity indexes of the substandard fly ash passed the requirements of TIS 2135 and ASTM C618. Utilization of the substandard fly ash as cement replacement led to higher expansion of mortar bars stored in water and sodium sulfate expansion as compared to that of the OPC mixture. However, sodium sulfate resistance of mortar mixtures improved when utilizing the substandard fly ash as sand replacement material. The compressive strength of concrete at all ages was higher with the increase of the content of the substandard fly ash as sand replacement material. When the substandard fly ash was used as cement replacement material in concrete, the carbonation depth increased. On the other hand, the use of the substandard fly ash as sand replacement material decreased the carbonation depth of the concrete. Utilization of the substandard fly ash, both to replace cement and/or fine aggregate, reduced the rapid chloride penetration of the concrete.

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