scholarly journals The impact of air content on the durability of concrete under combined sulphate and freezethaw attack

2018 ◽  
Vol 163 ◽  
pp. 05002 ◽  
Author(s):  
Julia Marczewska ◽  
Wojciech Piasta
Keyword(s):  
Air Entrainment ◽  
Sodium Sulphate ◽  
Sulphate Solution ◽  
Sulphate Attack ◽  
Portland Cement Concrete ◽  
Freezing And Thawing ◽  
Air Content ◽  
Concrete Damage ◽  
The Impact ◽  
Air Entrained Concrete

The aim of the study was to determine the optimal air content in concretes subjected a combination of exposure conditions. Five series of concretes with different air contents were tested. The article reports the experimental results of the combined sulphate expansion and freeze-thaw attack in ordinary Portland cement concrete. Some of the concrete samples were immersed in a 5% sodium sulphate solution for nine months, and then frozen in air and thawed in water. The resistance of concrete to plain freezing and thawing was also tested. In order to compare the degree of concrete damage in both environments, long-term linear deformations (expansion) and compressive strength of concretes were investigated. To explain the complex damaging process the air-void structure in concretes was investigated. The changes in concrete microstructure after storing in sodium sulphate solution were observed under the scanning electron microscope (SEM). The prior sulphate attack significantly accelerated the deterioration of non-air-entrained concrete and air-entrained concrete with low content of air voids. Optimal air entrainment will protect concrete from the harmful effects of the interaction of sulphate attack and freezethaw damage.

A Review on Fly Ash Based Geopolymer Rubberized Concrete

2016 ◽  
Vol 700 ◽  
pp. 183-196 ◽  
Author(s):  
Ahmad Azrem Azmi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Che Mohd Ruzaidi Ghazali ◽  
Andrei Victor Sandu ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Portland Cement ◽  
Unit Weight ◽  
Hardened Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Freezing And Thawing ◽  
Tire Rubber ◽  
Air Content ◽  
Waste Tire ◽  
Waste Tire Rubber

Utilization of waste materials such as waste tire rubber in the building industry can help prevent environmental pollution whilst contributing to the design of more economical buildings. Preliminary studies show that workable rubberized portland cement concrete mixtures can be made provided that appropriate percentages of tire rubber are used in such mixtures. This article provides the overview of some of published paper using tire waste rubber in portland cement concrete. The researchers mostly investigated the properties of fresh and hardened concrete. The workability, density, air content, unit weight, compressive strength, modulus of elasticity, freezing and thawing resistance, abrasion resistance and thermal properties of the waste tire rubber in concrete were discussed.

scholarly journals Impact Resistance and Sodium Sulphate Attack Testing of Concrete Incorporating Mixed Types of Recycled Plastic Waste

2021 ◽  
Vol 13 (17) ◽  
pp. 9521 ◽  
Author(s):  
Mahmoud Abu-Saleem ◽  
Yan Zhuge ◽  
Reza Hassanli ◽  
Mark Ellis ◽  
Md Mizanur Rahman ◽  
...  
Keyword(s):  
Transport Properties ◽  
Water Transport ◽  
Impact Resistance ◽  
Sodium Sulphate ◽  
Plastic Waste ◽  
Sulphate Attack ◽  
Impact Performance ◽  
Water Transport Properties ◽  
The Impact ◽  
Mixed Types

Impact resistance, water transport properties and sodium sulphate attack are important criteria to determine the performance of concrete incorporating mixed types of recycled plastic waste. Nine mixes were designed with different combinations of the three plastic types; Polyethylene terephthalate (PET), High density polyethylene (HDPE) and Polypropylene (PP). The plastic partially substituted the coarse aggregate (by volume) at various replacement ratios; 10%, 15%, 20% and 30%. The impact resistance and water transport properties were evaluated for nine mixes while sodium sulphate attack test was performed for three mixes. The results showed that the addition of mixed recycled plastic in concrete improved the impact resistance. The highest impact resistance improvement was achieved by R8 (PET + HDPE + PP) at 30% replacement which was 4.5 times better than the control mix. Water absorption results indicated a slight increase in all plastic mixes while contradictory results were observed for sorptivity test. Analysis of sodium sulphate attack results showed that incorporating 30% mixed plastic reduced the sodium sulphate resistance slightly due to the collective effect of plastic entrapping of sulphate ions after 80 cycles. This study has shown some positive results relating to the impact performance of Mixed Recycled Plastic Concrete (MRPC) which enhances its use in a sustainable way.

scholarly journals SURFACE SCALING RESISTANCE OF CONCRETE MODIFIED WITH BITUMINOUS ADDITION

2004 ◽  
Vol 10 (1) ◽  
pp. 25-30
Author(s):  
Marta Kosior-Kazberuk ◽  
Walery Jezierski
Keyword(s):  
Construction Industry ◽  
Portland Cement Concrete ◽  
Nacl Solution ◽  
Cement Concrete ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Cold Environments ◽  
Surface Scaling ◽  
Air Entrained Concrete ◽  
Scaling Resistance

Deterioration of concrete due to surface scaling is a very serious durability problem faced by the construction industry in cold environments. The experimental results of resistance to scaling due to cyclic freezing and thawing in the presence of 3 % NaCl solution (de‐icing agent) of not air‐entrained concrete with and without bituminous addition are presented and discussed in the paper. The results have been analysed using the analysis of variance and regression to verify the effect of addition content, number of freeze‐thaw cycles and the sort of cement on concrete ability to scaling. The statistical analysis showed that the bituminous addition significantly improves the scaling resistance of Portland cement concrete.

scholarly journals Performance of Self Compacting Concrete Incorporating Coarse Recycled Concrete Aggregates Exposed to Sulphate Attack

2020 ◽  
Vol 8 (5) ◽  
pp. 4797-4806
Keyword(s):  
Sodium Sulphate ◽  
Recycled Concrete ◽  
Sulphate Solution ◽  
Strength Development ◽  
Natural Material ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Sulphate Attack ◽  
Self Compacting Concrete ◽  
Coarse Recycled Concrete Aggregate

The interpretation of the performance of self-compacting concrete made with distinct proportion of coarse recycled concrete aggregate (RCA) (0%, 25%, 50%, 75% and 100%) exposed to sodium sulphate solution (50 gram/litre) under fully immersion condition is studied in this paper. Compressive and tensile strength development/degradation, mass change and length change under sulphate attack was surveyed for all tested units. According to the results it can be conclude that the use of coarse recycled concrete aggregate does not affect the development of strength of concrete with respect to natural material mixtures. It also conclude that for producing of sustainable and green concrete, the quality of used coarse recycled concrete aggregate is an important factor. The differ proportion of coarse recycled concrete aggregate & duration of immersion of concrete in sulphate solution also affect the concrete properties. Reusing recycled combination has twin property benefits: benefiting many tons dismantled concrete worldwide and conserving natural aggregates.

Elasticity of Calcium Silicate Brick Masonry Wall Due to Sulphate Attack

2010 ◽  
Vol 133-134 ◽  
pp. 195-200
Author(s):  
Ibrahim Mohamad H. Wan ◽  
B.H. Abu Bakar ◽  
M.A. Megat Johari ◽  
P.J. Ramadhansyah
Keyword(s):  
Relative Humidity ◽  
Modulus Of Elasticity ◽  
Calcium Silicate ◽  
Masonry Wall ◽  
Sodium Sulphate ◽  
Brick Masonry ◽  
Sulphate Solution ◽  
Masonry Structures ◽  
Sulphate Attack ◽  
Sulphate Concentration

The aim of this study is to investigate the behaviour of the calcium silicate brick masonry wall exposed to sulphate condition. This paper presents some result about the effect of sodium sulphate attack on the elasticity of the calcium silicate brick masonry structures. All specimens were cured under polythene sheet for 14 days in environmental controlled room with temperature of 25± 2°C and 80 ± 5% relative humidity. After curing, the specimens were exposed to sodium sulphate solution before tested at 14, 28, 56 and 180 days respectively. As a result, the modulus of elasticity of the calcium silicate brick masonry wall reduces with the increase of sulphate concentration.

scholarly journals Stability of Air Content in Fresh Concretes with PCE-Based Superplasticizers

2019 ◽  
Vol 60 (1) ◽  
pp. 145-158 ◽  
Author(s):  
Fahim Al-Neshawy ◽  
Teemu Ojala ◽  
Jouni Punkki
Keyword(s):  
Fresh Concrete ◽  
Cement Content ◽  
Mixing Time ◽  
Air Entrainment ◽  
Concrete Durability ◽  
Mixing Times ◽  
Air Content ◽  
The Stability ◽  
Air Entraining Agents ◽  
Air Entrained Concrete

Abstract Air contents of concrete are necessary for concrete durability in freeze-thaw exposure. According to the Finnish concrete code, the target value for air content varies between 4% and 5.5% for XF - exposure classes. Lately in Finland, some cases showed an elevation of air contents up to 15% in fresh air-entrained concrete at construction site and in drilled concrete samples. The objectives of this study were to investigate the stability of air entrainment by measuring the air content elevation 30 minutes and 60 minutes after concrete mixing and investigating the concrete sensitivity to segregation. Composition of concretes used in this study include 7 different combination of PCE based superplasticizer and air-entraining agent admixtures, cement content of 425 kg/m3, two consistency classes S3 with water to cement ration of 0.33 and F5 with water to cement ration of 0.38. One cement type was used for all concrete mixes. The concretes were mixed for 2 minutes and 5 minutes mixing times. The results show that the elevation of the air content of fresh concrete depends on the consistency of the concrete and on the used combination of superplasticizer and air-entraining agents. The higher consistency classes concretes have more risk of air elevation with some combinations of PCE-based superplasticizers and air-entraining agents. The results also indicate that short mixing time would not be enough to achieve total effectivity of some air-entraining agents, especially for higher consistency classes concrete.

A Predictive Model of the Impact of the Skidding System on Forest Soil in Severe Climatic Conditions

2020 ◽  
pp. 131-144
Author(s):  
S.E. Rudov ◽  
◽  
V.Ya. Shapiro ◽  
O.I. Grigoreva ◽  
I.V. Grigorev ◽  
...  
Keyword(s):  
Forest Soil ◽  
Warm Season ◽  
Climatic Conditions ◽  
Soil Freezing ◽  
Class Iii ◽  
Freezing And Thawing ◽  
Metal Structures ◽  
Rapid Adjustment ◽  
Soil Freezing And Thawing ◽  
The Impact

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

scholarly journals Titanium Dioxide Presents a Different Profile in Dextran Sodium Sulphate-Induced Experimental Colitis in Mice Lacking the IBD Risk Gene Ptpn2 in Myeloid Cells

2021 ◽  
Vol 22 (2) ◽  
pp. 772
Author(s):  
Javier Conde ◽  
Marlene Schwarzfischer ◽  
Egle Katkeviciute ◽  
Janine Häfliger ◽  
Anna Niechcial ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Titanium Dioxide ◽  
Genetic Risk ◽  
Intestinal Inflammation ◽  
Sodium Sulphate ◽  
Food Additive ◽  
Wild Type ◽  
Dextran Sodium Sulphate ◽  
Risk Gene ◽  
The Impact

Environmental and genetic factors have been demonstrated to contribute to the development of inflammatory bowel disease (IBD). Recent studies suggested that the food additive; titanium dioxide (TiO2) might play a causative role in the disease. Therefore, in the present study we aimed to explore the interaction between the food additive TiO2 and the well-characterized IBD risk gene protein tyrosine phosphatase non-receptor type 2 (Ptpn2) and their role in the development of intestinal inflammation. Dextran sodium sulphate (DSS)-induced acute colitis was performed in mice lacking the expression of Ptpn2 in myeloid cells (Ptpn2LysMCre) or their wild type littermates (Ptpn2fl/fl) and exposed to the microparticle TiO2. The impact of Ptpn2 on TiO2 signalling pathways and TiO2-induced IL-1β and IL-10 levels were studied using bone marrow-derived macrophages (BMDMs). Ptpn2LysMCre exposed to TiO2 exhibited more severe intestinal inflammation than their wild type counterparts. This effect was likely due to the impact of TiO2 on the differentiation of intestinal macrophages, suppressing the number of anti-inflammatory macrophages in Ptpn2 deficient mice. Moreover, we also found that TiO2 was able to induce the secretion of IL-1β via mitogen-activated proteins kinases (MAPKs) and to repress the expression of IL-10 in bone marrow-derived macrophages via MAPK-independent pathways. This is the first evidence of the cooperation between the genetic risk factor Ptpn2 and the environmental factor TiO2 in the regulation of intestinal inflammation. The results presented here suggest that the ingestion of certain industrial compounds should be taken into account, especially in individuals with increased genetic risk

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