An alternative method for performance improvement of ultra-high performance concrete by internal curing: Role of physicochemical properties of saturated lightweight fine aggregate

2021 ◽  
Vol 312 ◽  
pp. 125373
Author(s):  
Peiliang Shen ◽  
Jian-Xin Lu ◽  
Linnu Lu ◽  
Yongjia He ◽  
Fazhou Wang ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Performance Improvement ◽  
High Performance ◽  
High Performance Concrete ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Ultra High Performance Concrete ◽  
Alternative Method

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.

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.

Studies on ultra high performance concrete incorporating copper slag as fine aggregate

2015 ◽  
Vol 77 ◽  
pp. 233-240 ◽  
Author(s):  
P.S. Ambily ◽  
C. Umarani ◽  
K. Ravisankar ◽  
Prabhat Ranjan Prem ◽  
B.H. Bharatkumar ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Copper Slag ◽  
Fine Aggregate ◽  
Ultra High Performance Concrete

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.

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