scholarly journals Freezing and thawing resistance of internally cured high performance concrete

2018 ◽  
Vol 162 ◽  
pp. 02011
Author(s):  
Muthana Saadi ◽  
Tareq al-Attar ◽  
Shatha Hasan
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Cast Concrete ◽  
Curing Method ◽  
Compressive And Flexural Strengths ◽  
Limestone Dust ◽  
Freezing And Thawing Cycles

The behavior of internally cured high performance concrete, HPC, exposed to freezing and thawing cycles, was investigated. Two saturated curing agents, Limestone dust and powder of Porcelanite rock, were used to facilitate internal curing for concrete. These agents were used as partial replacements of fine aggregate in two volumetric percentages, 20 and 30 percent. The cast concrete specimens were separated in two groups according to curing method: water-cured and sealed (only internally-cured) specimens. The concrete specimens were subjected to three exposure systems, F0: without freezing and thawing, and F1 and F2: with 50 and 100 cycles of freezing and thawing, respectively. The freezing and thawing test was done as stipulated by the ASTM C666. The conducted tests for each exposure were: compressive and flexural strengths. The results revealed that internal curing does not enhance the concrete resistance to freezing and thawing cycles. Using saturated agents has increased the moisture content of concrete and makes it more vulnerable to frost action deterioration. Sealed specimens for all investigated mixes showed lower reductions in strength than water-cured ones. The lesser water content of these mixes may be the reason for that behavior.

scholarly journals Effect of Mineral Aggregates and Chemical Admixtures as Internal Curing Agents on the Mechanical Properties and Durability of High-Performance Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2090 ◽  
Author(s):  
Francisco Javier Vázquez-Rodríguez ◽  
Nora Elizondo-Villareal ◽  
Luz Hypatia Verástegui ◽  
Ana Maria Arato Tovar ◽  
Jesus Fernando López-Perales ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ions ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Pumice Stone ◽  
Chemical Admixtures ◽  
Mineral Aggregates

In the present work, the effect of mineral aggregates (pumice stone and expanded clay aggregates) and chemical admixtures (superplasticizers and shrinkage reducing additives) as an alternative internal curing technique was investigated, to improve the properties of high-performance concrete. In the fresh and hardened state, concretes with partial replacements of Portland cement (CPC30R and OPC40C) by pulverized fly ash in combination with the addition of mineral aggregates and chemical admixtures were studied. The physical, mechanical, and durability properties in terms of slump, density, porosity, compressive strength, and permeability to chloride ions were respectively determined. The microstructural analysis was carried out by scanning electronic microscopy. The results highlight the effect of the addition of expanded clay aggregate on the internal curing of the concrete, which allowed developing the maximum compressive strength at 28 days (61 MPa). Meanwhile, the replacement of fine aggregate by 20% of pumice stone allowed developing the maximum compressive strength (52 MPa) in an OPC-based concrete at 180 days. The effectiveness of internal curing to develop higher strength is attributed to control in the porosity and a high water release at a later age. Finally, the lowest permeability value at 90 days (945 C) was found by the substitutions of fine aggregate by 20% of pumice stone saturated with shrinkage reducing admixture into pores and OPC40C by 15% of pulverized fly ash. It might be due to impeded diffusion of chloride ions into cement paste in the vicinity of pulverized fly ash, where the pozzolanic reaction has occurred. The proposed internal curing technology can be considered a real alternative to achieve the expected performance of a high-performance concrete since a concrete with a compressive strength range from 45 to 67 MPa, density range from 2130 to 2310 kg/m3, and exceptional durability (< 2000 C) was effectively developed.

92-MPa Air-Entrained High-Performance Concrete Using Tennessee Materials

2000 ◽  
Vol 1698 (1) ◽  
pp. 24-29 ◽  
Author(s):  
L. K. Crouch ◽  
Heather J. Sauter ◽  
Jacob A. Williams
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Maximum Size ◽  
Mixture Design ◽  
Unit Weight ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Aggregate Gradation ◽  
Static Modulus ◽  
Static Modulus Of Elasticity

An air-entrained high-performance concrete (HPC) mixture design for prestressed bridge beams was developed in an attempt to interest the Tennessee Department of Transportation. The mixture contained locally available, 19-mm maximum-size limestone as the coarse aggregate and a manufactured limestone fine aggregate. A dense, combined aggregate gradation was used to lower water demand and thus enhance durability. Type II portland cement, microsilica, and Class C fly ash were used as binder materials. The resulting w/(c + p) was 0.22. Twelve 0.028-m3 batches of the HPC were mixed for the study. The mixture design produced an average air content of 4.1 percent and an average slump of 72 mm. Although it contained 4.1 percent air, the mixture remained very dense, with an average unit weight of 2422 kg/m3. Average compressive strengths of 72.6, 63.3, 84.8, and 92.9 MPa were achieved at simulated release at 7, 28, and 56 days, respectively. Measured static modulus of elasticity at 28 days agreed with ACI 363R-92 equations within 2 percent. Further, after 600 freezing and thawing cycles, the average durability factor of two prismatic specimens was 100, and visible damage was minimal.

scholarly journals The use of ceramics as an internal curing agent in high performance concrete with variable temperature curing to improve mechanical characteristics

2022 ◽  
Vol 961 (1) ◽  
pp. 012024
Author(s):  
Abdulrasool Thamer Abdulrasool ◽  
Noor R. Kadhim ◽  
Safaa S. Mohammed ◽  
Ahmed Abdulmueen Alher
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Mechanical Characteristics ◽  
High Performance Concrete ◽  
Variable Temperature ◽  
Porous Ceramic ◽  
Autogenous Shrinkage ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Fine Aggregates

Abstract Concrete curing is one of the most significant factors in the development of compressive strength, and a high temperature difference during curing may reduce strength. The microcracks created in the concrete as a result of the constant temperature change cause this exudation. Internal curing has become popular for decreasing the risk of early-age cracking in high-performance concrete by limiting autogenous shrinkage (HPC). This study looks at the effectiveness of internal wet curing offered by a new kind of aggregate called “recycled waste porous ceramic fine aggregates”. The evolution of measured mechanical characteristics is examined on three distinct HPCs, both with and without internal curing materials. Ceramic fine aggregates were used to replace two different quantities of regular weight fine aggregate. Ceramic fine aggregates were shown to be quite beneficial for internal cure. It has been discovered that incorporating 20% ceramic fine aggregates into HPC improves the properties of the material, resulting in low internal stress and a large improvement in compressive strength. It should be emphasized that, unlike some traditional lightweight aggregates, no loss in compressive strength has been seen for the various quantities of ceramic fine aggregates introduced at either early or later ages.

scholarly journals Execution of Internal Curing Method on Concrete using Pre-Soaked Light Weight Aggregate

2019 ◽  
Vol 8 (9) ◽  
pp. 1345-1349
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Internal Curing ◽  
Light Weight ◽  
Concrete Technology ◽  
Curing Conditions ◽  
Super Plasticizer ◽  
Curing Method ◽  
Flexural Tests

Low water-cement proportion solid mixes have been progressively advanced for use in Civil Engineering foundation because of potential changes in quality and sturdiness. Notwithstanding their expanded quality and diminished porous nature, the structures are defenseless to early-age splitting. Techniques have been created to lessen the breaking in structures. One such strategy is interior curing. The utilization of internal curing operators can give an adequate volume of water by methods for light weight aggregates (LWA). Notwithstanding the volume of water gave by the LWA, the dispersion of the LWA assumes a fundamental part in the viability of interior curing. Recently, high-performance concrete (HPC) has been increasingly used in practice, with the development of concrete technology and the introduction of super plasticizer and silica fume. High performance concrete is a concrete, which has far super quality and sturdiness attributes when contrasted with regular cement. The present examination researches the quality related properties of HPC specimens like flexural quality utilizing silica fume, super plasticizer in the inward curing technique. The mix proportion of 1:1.76:2.52:0.36 is utilized to cast pillars (100mm X 150mm X 1700mm). The HPC specimens are thrown with supplanting of concrete with 12% of silica smoke and expansion of 6%,12%,20% LWA vermiculite. From the pressure test result, ideal rate substitution of LWA is discovered and utilized for throwing bar. The aftereffects of flexural tests directed on shaft specimens demonstrates that 6% substitution of vermiculite gives the higher quality in both water and inward curing conditions.

scholarly journals Effect Of Attapulgite as Internal Curing in High-Performance Concrete with Variable Temperature Curing to Enhance Mechanical Properties

2022 ◽  
Vol 961 (1) ◽  
pp. 012054
Author(s):  
Abdulrasool Thamer Abdulrasool ◽  
Safaa S. Mohammed ◽  
Noor R. Kadhim ◽  
Yasir N. Kadhim
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Variable Temperature ◽  
Normal Weight ◽  
Internal Curing ◽  
Large Temperature ◽  
Fine Aggregate ◽  
Fine Aggregates

Abstract One of the most important elements in the development of compressive strength is concrete curing, and a large temperature differential during curing may decrease strength. This exudation is caused by microcracks in the concrete caused by the continuous temperature fluctuation. By minimizing autogenous shrinkage, internal curing has become popular for reducing the danger of early-age cracking in high-performance concrete (HPC). The efficacy of internal wet curing provided by fine Attapulgite aggregate is investigated in this research. On three different HPCs, both with and without internal curing materials, the development of observed mechanical properties is investigated. Two different amounts of normal weight fine aggregate were replaced with attapulgite fine aggregates. Internal cure has been found to benefit from attapulgite fine aggregates. It has been found that adding 20% Attapulgite fine aggregates to HPC enhances the material’s characteristics, resulting in low internal stress and a significant increase in compressive strength. It should be noted that, unlike certain conventional lightweight aggregates, the different amounts of Attapulgite fine aggregates added at various ages have shown no decrease in compressive strength.

Effect of Copper Slag as a Fine Aggregate on the Durability Characteristics of High-Performance Concrete (HPC) Containing Silica Fume

2020 ◽  
Vol 07 (02) ◽  
pp. 1-10
Author(s):  
Rizwan Ahmad Khan ◽  
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Copper Slag ◽  
Chloride Penetration ◽  
Interfacial Transition Zone ◽  
Fine Aggregate ◽  
Fresh Properties ◽  
Fine Aggregates ◽  
Effect Of Copper

This paper investigates the fresh and durability properties of the high-performance concrete by replacing cement with 15% Silica fume and simultaneously replacing fine aggregates with 25%, 50%, 75% and 100% copper slag at w/b ratio of 0.23. Five mixes were analysed and compared with the standard concrete mix. Fresh properties show an increase in the slump with the increase in the quantity of copper slag to the mix. Sorptivity, chloride penetration, UPV and carbonation results were very encouraging at 50% copper slag replacement levels. Microstructure analysis of these mixes shows the emergence of C-S-H gel for nearly all mixes indicating densification of the interfacial transition zone of the concrete.

scholarly journals Abrasion Resistance of Ultra-High-Performance Concrete for Railway Sleepers

2021 ◽  
Author(s):  
Ariful Hasnat ◽  
Nader Ghafoori
Keyword(s):  
Prestressed Concrete ◽  
Abrasion Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Positive Influence ◽  
Cementitious Material ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Ultra High Performance Concrete

AbstractThis study aimed to determine the abrasion resistance of ultra-high-performance concretes (UHPCs) for railway sleepers. Test samples were made with different cementitious material combinations and varying steel fiber contents and shapes, using conventional fine aggregate. A total of 25 UHPCs and two high-strength concretes (HSCs) were selected to evaluate their depth of wear and bulk properties. The results of the coefficient of variation (CV), relative gain in abrasion, and abrasion index of the studied UHPCs were also obtained and discussed. Furthermore, a comparison was made on the resistance to wear of the selected UHPCs with those of the HSCs typically used for prestressed concrete sleepers. The outcomes of this study revealed that UHPCs displayed excellent resistance against abrasion, well above that of HSCs. Amongst the utilized cementitious material combinations, UHPCs made with silica fume as a partial replacement of cement performed best against abrasion, whereas mixtures containing fly ash showed the highest depth of wear. The addition of steel fibers had a more positive influence on the abrasion resistance than it did on compressive strength of the studied UHPCs.

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