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1

The effects of Nano SiO2 and Silica Fume on the properties of concrete

Tran Huu-Bang, Phan Vu To-Anh

Archives of Civil Engineering

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2022

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Vol. 68, nr 2

391-407

EN

This study investigates the effects of Nano SiO2 (NS) and Silica fume (SF) on the mechanical properties and durability of Portland cement concrete. On specimens with varying NS and SF concentrations, compressive strength, flexural strength, abrasion resistance, elastic modulus, and chloride ion penetration were all tested. All specimens were subjected to the proposed method/technique cured at the ages of 3, 7, 28, and 60 days. NS particles were added to cement concrete at various replacements of 0, 0.5, 1.0, 1.5, and 2.0% by the mass of the binder. The water/binder ratio has remained at 0.37 for all mixes. Then, for cement-concrete were prepared 45 MPa (C45) with NS and SF. The specimens confirm the new method effectiveness evaluation were prepared under two different categories: (1) Portland cement replacement with NS of 0%, 0.5%, 1.0%, 1.5%, and 2.0%, by weight for adhesives; (2) Portland cement replacement with NS of 0.5%, 1.0% and each NS content in combination with SF of 5%, 10%, and 15%, respectively, by weight for adhesives. The results indicated that the abrasion resistance and Chloride ion penetration of concrete containing NS and SF are improved. Finally, an analytical model for forecasting the Elastic modulus, flexural strength, and compressive strength of cement concrete was established from obtained data.

2

Essential factors for the changes in concrete during electrochemical extraction

Alsabry A.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 2

443--450

EN

The objective of the article is to present one of the most significant factors affecting electrochemical removal of chloride ions from concrete. Based on the literature findings, tests were carried out on specimens containing chloride admixtures introduced to the cement grout, on elements subjected to chloride penetration from the solution in laboratory conditions and on fragments of constructions penetrated by chlorides as a result of a long-term exposure to seawater.

3

Odporność betonów zawierających popiół lotny ze współspalania węgla kamiennego i biomasy na wnikanie jonów chlorkowych

Kosior-Kazberuk M.

Budownictwo i Inżynieria Środowiska

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2010

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Vol. 1, no. 2

131-136

PL

Praktyczne wykorzystanie nowego odpadu przemysłu energetycznego, jakim jest popiół lotny pochodzący ze spalania innych paliw niż węgiel wymaga oceny jego właściwości użytkowych. W pracy zaprezentowano wyniki badań nad wpływem popiołu lotnego ze współspalania węgla kamiennego i biomasy drzewnej na odporność betonu na wnikanie jonów chlorkowych. Odporność betonu oceniono na podstawie efektywnego współczynnika dyfuzji określonego w warunkach ustalonego przepływu jonów Cl-. Badano betony, w których część cementu (od 0 do 25%) zastąpiono popiołem. Na podstawie wyników badań stwierdzono, że dodatek popiołu lotnego ze współspalania powoduje ograniczenie przepuszczalności betonu dla chlorków. Współczynnik dyfuzji malał wraz ze wzrostem zawartości popiołu w mieszance betonowej i z wiekiem betonu.

EN

The practical utilization of new by-product of the power industry – the fly ash from the combustion of other fuels than coal – demands the assessment of its applicable properties. The paper deals with the research concerning the influence of the fly ash from co-combustion of hard coal and wood biomass on the resistance of concrete to chloride ion penetration. The resistance of concrete was evaluated on the basis of the effective diffusivity coefficient determined in steady-state migration test. The investigations were carried out for concretes in which the part of Portland cement (from 0 to 25%) was replaced by the ash. On the basis of test results, it was found that the addition of the fly ash from the co-combustion caused the significant reduction of the concrete permeability for chlorides. The diffusivity decreased with the increase in percentage of ash in the concrete mixture as well as with the concrete age.