scholarly journals Producing Heavyweight High-Performance Concrete by Using Black Sand as Newly Shielding Construction Material

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5353
Author(s):  
Khaled A. Eltawil ◽  
Mohamed G. Mahdy ◽  
Osama Youssf ◽  
Ahmed M. Tahwia
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Elevated Temperatures ◽  
Gamma Ray ◽  
High Performance Concrete ◽  
Construction Material ◽  
Construction Materials ◽  
Linear Attenuation Coefficient ◽  
Fine Aggregate ◽  
Black Sand

Experimental work was carried out to study new fine aggregate shielding construction materials, namely black sand (BS). The BS effect on the mechanical, durability, and shielding characteristics of heavyweight high-performance concrete (HWHPC) was evaluated. This study aimed at improving various HWHPC properties, concertedly. Fifteen mixtures of HWHPC were made, with various variables, including replacing 10% and 15% of the cement with fly ash (FA) and replacing normal sand by BS at various contents (15%, 30%, 45%, 60%, 75%, and 100%). The test specimens were subjected to various exposure conditions, including elevated temperatures, which ranged from 250 °C to 750 °C, for a duration of 3 h; magnesium sulfate (MS) exposure; and gamma-ray exposure. The effects of elevated temperature and sulfate resistance on concrete mass loss were examined. The results revealed that BS is a promising shielding construction material. The BS content is the most important factor influencing concrete compressive strength. Mixes containing 15% BS demonstrated significantly better strength compared to the control mixes. Exposure to 250 °C led to a notable increase in compressive strength. BS showed a significant effect on HWHPC fire resistance properties, especially at 750 °C and a significant linear attenuation coefficient. Using 10% FA with 15% BS was the most effective mixing proportion for improving all HWHPC properties concertedly, especially at greater ages.

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.

The ability of high performance concrete to resist high temperature

2017 ◽  
Vol 8 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Hassan A.M. Mhamoud ◽  
Jia Yanmin
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mass Loss ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Sharp Decrease ◽  
Test Results ◽  
Content Type ◽  
Chinese Standard

Purpose This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to mass loss and residual compressive and flexural strength. Design/methodology/approach Two mixtures were developed to test. The first mixture, OPC, was used as the control, and the second mixture was HPC. After 28 days under water (per Chinese standard), the samples were tested for compressive strength and residual strength. Findings The test results showed that at elevated temperatures of up to 500ºC, each mixture experienced mass loss. Below this temperature, the strength and the mass loss did not differ greatly. Originality/value When adding a 10 per cent silica fume, 25 per cent fly, 25 per cent slag to HPC, the compressive strength increased by 17 per cent and enhanced the residual compressive strength. A sharp decrease was observed in the residual flexural strength of HPC when compared to OPC after exposure to temperatures of 700ºC.

scholarly journals The Impact of Nano Clay on Normal and High-Performance Concrete Characteristics: A Review

2022 ◽  
Vol 961 (1) ◽  
pp. 012085
Author(s):  
Aseel Mansi ◽  
Nadhim Hamah Sor ◽  
Nahla Hilal ◽  
Shaker M A Qaidi
Keyword(s):  
Flexural Strength ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Construction Materials ◽  
Sulfate Attack ◽  
Review Article ◽  
Nucleation Sites ◽  
Nano Clay ◽  
The Impact

Abstract The use of nano clay to improve the qualities of construction materials and engineering applications has attracted a lot of discussion in recent years. This review article summarizes the influence of nano clay as a cement substitute and supplement on the performance of conventional and high-performance concrete. The addition of nano clay to high performance concrete revealed an increase in compressive and flexural strength, as well as durability attributes such as resistance to elevated temperatures and sulfate attack, while simultaneously decreasing porosity, permeability, and water absorption. This enhancement is a result of nano clay’s roles as nano reinforcements, nanofillers, nucleation sites, and reactive pozzolans, which promote hydration and increase material characteristics.

scholarly journals Behavior of HPC with Fly Ash after Elevated Temperature

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Huai-Shuai Shang ◽  
Ting-Hua Yi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Ultrasonic Velocity ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Surface Characteristics ◽  
Effect Of Temperature ◽  
Cleavage Strength

For use in fire resistance calculations, the relevant thermal properties of high-performance concrete (HPC) with fly ash were determined through an experimental study. These properties included compressive strength, cubic compressive strength, cleavage strength, flexural strength, and the ultrasonic velocity at various temperatures (20, 100, 200, 300, 400 and 500∘C) for high-performance concrete. The effect of temperature on compressive strength, cubic compressive strength, cleavage strength, flexural strength, and the ultrasonic velocity of the high-performance concrete with fly ash was discussed according to the experimental results. The change of surface characteristics with the temperature was observed. It can serve as a reference for the maintenance, design, and the life prediction of high-performance concrete engineering, such as high-rise building, subjected to elevated temperatures.

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.

Effect of Partial Substitution of Fine Aggregate with Copper Slag on Mechanical and Durability of High Performance Concrete-A Review

2020 ◽  
Vol 07 (01) ◽  
pp. 1-11
Author(s):  
Rizwan Ahmad Khan ◽  
Keyword(s):  
Construction Industry ◽  
High Performance ◽  
High Performance Concrete ◽  
Construction Materials ◽  
Copper Slag ◽  
Partial Substitution ◽  
Fine Aggregate ◽  
Natural Sand ◽  
Severe Problem ◽  
Fine Aggregates

The challenge before the construction industry is to meet the demand of the efficient and economically viable construction materials posed by the huge infrastructural needs. Many nations are observing an expeditious growth in the field of construction necessitating the utilization of natural reserves for the expansion of infrastructure. This expansion is giving a warning to available reserves of nature. The natural ingredients, fine aggregates and coarse aggregate constitute more than 70% volume of the concrete. The availability of these resources is decreasing at a very high pace. In fact due to the severe problem with the availability of natural sand, the construction industry is faced with the pressing need to consider available options to lessen the reliance on natural aggregates. Copper slag being a waste material, can be used as an option for fine aggregates. The substitution of fine aggregate from nature with waste materials from industries such as copper slag offers economic and technical dominance, which are of pronounced significance in the present scenario. This study is, based on the critical review of the development of High Performance Concrete (HPC) by replacing fine aggregate with copper slag by observing various other researches and reviews. The key intent of this paper is to closely look at the copper slag utility as an unconventional material to be used as a substitute of fine aggregate and its effect on mechanical and durability parameters of HPC.

scholarly journals Non-Tuned Machine Learning Approach for Predicting the Compressive Strength of High-Performance Concrete

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1023
Author(s):  
Abobakr Khalil Al-Shamiri ◽  
Tian-Feng Yuan ◽  
Joong Hoon Kim
Keyword(s):  
Machine Learning ◽  
Compressive Strength ◽  
Prediction Model ◽  
Extreme Learning Machine ◽  
High Performance ◽  
High Performance Concrete ◽  
Fine Aggregate ◽  
Input Variables ◽  
Prediction Reliability ◽  
Learning Machine

Compressive strength is considered as one of the most important parameters in concrete design. Time and cost can be reduced if the compressive strength of concrete is accurately estimated. In this paper, a new prediction model for compressive strength of high-performance concrete (HPC) was developed using a non-tuned machine learning technique, namely, a regularized extreme learning machine (RELM). The RELM prediction model was developed using a comprehensive dataset obtained from previously published studies. The input variables of the model include cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate, and age of specimens. k-fold cross-validation was used to assess the prediction reliability of the developed RELM model. The prediction results of the RELM model were evaluated using various error measures and compared with that of the standard extreme learning machine (ELM) and other methods presented in the literature. The findings of this research indicate that the compressive strength of HPC can be accurately estimated using the proposed RELM model.

Static, dynamic mechanical properties and microstructure characteristics of ultra-high performance cementitious composites

2012 ◽  
Vol 19 (3) ◽  
pp. 237-245 ◽  
Author(s):  
Wenhua Zhang ◽  
Yunsheng Zhang ◽  
Guorong Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
Steel Fiber ◽  
Construction Material ◽  
Dynamic Mechanical Properties ◽  
Fine Aggregate ◽  
Dynamic Impact ◽  
Dynamic Mechanical ◽  
Reactive Powder

AbstractA new type of construction material named ultra-high performance cementitious composite (UHPCC) was developed in order to reduce the production cost and energy consumption of reactive powder concrete (RPC). Six different mixture proportions of UHPCC were designed, and their properties, including workability (slump test), static mechanical properties (compressive strength and flexure strength), and dynamic mechanical properties (dynamic compressive strength, toughness and fracture pattern), were investigated. Finally, the microstructure of the UHPCC was studied. The experiment result indicate that the compressive and flexural strength of UHPCC can reach 150–200 MPa and 15–50 MPa under standard curing conditions, respectively, which is close to RPC200. Besides, the steel fiber has significant improvement on mechanical properties of UHPCC. The dynamic impact test results show that UHPCC has obvious strain rate effects. Besides, UHPCC exhibits excellent properties to resist dynamic impact. The microstructure investigation showed that UHPCC has dense microstructures and very strong bonds of the interfacial transition zone between cementitious paste and fine aggregate steel fiber.

Study on early Mechanical Performance of High Performance Concrete with Low Clinker Influenced by Rubber Powder

2014 ◽  
Vol 584-586 ◽  
pp. 1738-1741
Author(s):  
Qing Hai Meng ◽  
Li Hua Lv ◽  
Xu Yan
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
High Performance ◽  
Bending Strength ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Fine Aggregate ◽  
Rubber Powder ◽  
Concrete Mechanical Properties ◽  
Strength And Ductility

Selecting rubber powders, which is divided into 80 mesh and 150 mesh, as the research object, to understand the influence of high performance of lower clinker concrete mechanical properties of rubber powder with different varieties and volume. Taking the compressive strength, flexural strength and ratio of flexural strength to compressive strength as an indicator, the thesis explores the influence of the high performance concrete with low clinker, which rubber powder are mixed into as fine aggregate, on the compressive strength bending strength and ductility.

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