scholarly journals Effect of Pharmaceutical Wastes Usage as Partial Replacement of Cement on the Durability of High-Performance Concrete

2018 ◽  
Vol 13 ◽  
pp. 218-221
Author(s):  
Talah Aissa ◽  
Belaid Rachid ◽  
Fattoum Kharchi
Author(s):  
Ariful Hasnat ◽  
Nader Ghafoori

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.


2019 ◽  
Vol 292 ◽  
pp. 108-113 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Roman Chylík ◽  
Zdeněk Prošek

The paper describes an experimental program focused on the research of high performance concrete with partial replacement of cement by fly ash. Four mixtures were investigated: reference mixture and mixtures with 10 %, 20 % and 30 % cement weight replaced by fly ash. In the first stage, the effect of cement replacement was observed. The second phase aimed at the influence of homogenization process for the selected 30% replacement on concrete properties. The analysis of macroscopic properties followed compressive strength, elastic modulus and depth of penetration of water under pressure. Microscopic analysis concentrated on the study of elastic modulus, porosity and mineralogical composition of cement matrix using scanning electron microscopy, spectral analysis and nanoindentation. The macroscopic results showed that the replacement of cement by fly ash notably improved compressive strength of concrete and significantly decreased the depth of penetration of water under pressure, while the improvement rate increased with increasing cement replacement (strength improved by 18 %, depth of penetration by 95 % at 30% replacement). Static elastic modulus was practically unaffected. Microscopic investigation showed impact of fly ash on both structure and phase mechanical performance of the material.


2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.


Author(s):  
Eniyachandramouli Gunasekaran ◽  
Govindhan Shanmugam ◽  
Ranjith Selvan Karuppusamy ◽  
Vijay Manoharan ◽  
Preetha Vellaichamy

10.29007/jxp9 ◽  
2018 ◽  
Author(s):  
Shashi Kant Sharma ◽  
Aniruddha Chopadekar ◽  
Samarth Bhatia

Slurry infiltrated fibrous concrete (SIFCON) is a new and unique type of high performance concrete invented by Lankard in 1979, containing high percentage of fiber about 6% to 20% by volume. SIFCON possesses high strength as well as large ductility and has excellent potential for structural application. The matrix in SIFCON has no coarse aggregate but high cementitious content. The aim of study is to evaluate the performance of SIFCON mortar with lower fiber percentage and to minimize the fine aggregate usage by replacing it with industrial waste i.e. steel slag. Thereby, it also helps in effective disposal of industrial waste and helps in mitigating environmental pollution. The main objective of this study is to determine the effect of partial replacement of sand with steel slag on the mechanical properties of SIFCON mortar. The experimental program was carried out with 2%, 3% and 4% of fiber content by volume combined with replacement of sand by steel slag in proportion of 10% and 20% by weight. For this purpose, compressive strength, flexural strength, split tension and impact strength of SIFCON specimens were tested after 7 and 28 days of curing, yielding positive results.


Author(s):  
Wojciech Kubissa ◽  
Roman Jaskulski

In the article the possibility of using surface blast-cleaning waste (copper slag based) as a replacement of fine aggregate in high performance concrete manufacturing was presented. Concrete with w/c ratio 0.45 and 360 kg/m3 dosage of cements: CEM I 42.5R, CEM II/B-V 42.5N and CEM III/A 42.5N was tested. The consistency measured in table flow test was assumed as 420 ± 30 mm so superplasticizer was used. The replacement rate of the fine aggregate 0–2 mm with the copper slag (CS) waste was 66 %. Concrete mixtures with sand served as reference. The performed tests focused on: compressive and tensile strength (both after 28 days), sorptivity, free water absorption capacity, Torrent air permeability, and chloride ingress depth after salt fog treatment. A freeze resistance test was also carried out according to PN-B-06265. The obtained results showed that the strength and some other tested properties of concrete mixtures with copper slag waste were similar or better than those of the mixtures with sand. The results of the tests indicate that the concrete with copper slag waste is more tight than the concrete with sand and therefore is more durable.


2021 ◽  
Vol 1205 (1) ◽  
pp. 012008
Author(s):  
M Drdlova ◽  
P Bibora ◽  
V Prachar

Abstract This study introduces cementitious composite with rubber granulate and waste steel fibres as a new material for construction industry with an enhanced energy absorption capability and impact toughness. Detailed research on physico-mechanical properties of high-performance concrete with waste steel fibres and partial replacement of the aggregates by rubber granulate was performed, with emphasis on impact energy absorption potential. Different aggregate replacement ratios (0–30% wt.) and fibre amount (0–3% wt.) were investigated. The influence of rubber sizes, rubber content and steel fibre content on the mechanical parameters of the rubberized concrete at both quasistatic and dynamic loads was evaluated and discussed. With increasing amount of rubber granulate, the concrete suffered from reduction of its mechanical parameters – compressive and flexural strength, however the energy dissipation capability showed rising trend. This study demonstrated the potential of rubberized concrete with waste steel fibres for use in structures with higher impact resistance requirements.


Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 75
Author(s):  
David O. Nduka ◽  
Babatunde J. Olawuyi ◽  
Olabosipo I. Fagbenle ◽  
Belén G. Fonteboa

The present study examines the durability properties of Class 1 (50–75 MPa) high-performance concrete (HPC) blended with rice husk ash (RHA) as a partial replacement of CEM II B-L, 42.5 N. Six HPC mixes were prepared with RHA and used as 5%, 10%, 15%, 20%, 25%, and 30% of CEM II alone and properties are compared with control mix having only CEM II. The binders (CEM II and RHA) were investigated for particle size distribution (PSD), specific surface area (SSA), oxide compositions, mineralogical phases, morphology, and functional groups using advanced techniques of laser PSD, Brunauer–Emmett–Teller (BET), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared/attenuated total reflection (FTIR/ATR), respectively, to understand their import on HPC. Durability properties, including water absorption, sorptivity, and chemical attack of the HPC samples, were investigated to realise the effect of RHA on the HPC matrix. The findings revealed that the durability properties of RHA-based HPCs exhibited an acceptable range of values consistent with relevant standards. The findings established that self-produced RHA would be beneficial as a cement replacement in HPC. As the RHA is a cost-effective agro-waste, a scalable product of RHA would be a resource for sustainable technology.


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