scholarly journals EFFECT OF WATER ABSORPTION PROPERTY OF COARSE AGGREGATE ON DRYING SHRINKAGE OF CONCRETE

2021 ◽  
Vol 74 (1) ◽  
pp. 178-184
Author(s):  
Toshinari HAYASHI ◽  
Atsushi SAITO ◽  
Shinichi MIYAZATO
2011 ◽  
Vol 391-392 ◽  
pp. 1168-1172
Author(s):  
Xiao Chun Fang ◽  
Sheng Gao Wang ◽  
Ming Yang Wang ◽  
Kai Wei Xu

A study was made on plasma-initiated polymerization of polyacrylamide (PAM) with high superabsorbent property. The viscosity-averaged molecular weight Mη of this PAM was 6.2×106g/mol in the measurement of viscosity by using water as solvent. Its conversion and water absorption calculated are 70% and 300g/g respectively. The effects of plasma discharge time, polymerization temperature and duration on the conversion and the molecular weight of the products were also investigated. The results of this study suggested that the method of plasma initiated polymerization could greatly enhance the molecular weight and water absorption property of the polymer.


2014 ◽  
Vol 584-586 ◽  
pp. 1188-1191
Author(s):  
Peng Fei Li ◽  
Xian Chun Zheng ◽  
Ling Feng Ji

This paper test the strength intensity,water absorption property of 10 baking—free bricks using the matrix cementing component in waster concrete as the material,studies the effect of m~ing ratio and maintenance time on pmpe~y to get the best mKing ratio of this kind of brick.It also analyzes the intension resources of this brick.


2020 ◽  
Vol 5 (12) ◽  
pp. 92-95
Author(s):  
Pauline N. Obianuko ◽  
Tessy U. Onuegbu

The use of plant fibres as reinforcement in composite materials is finding increasing interest in the automotive and building industry, and the properties of plant fibre composites have been addressed in numerous research studies. The replacement of synthetic fibres with natural fibres in composites is based on their renewable and environmentally friendly nature. The aim of this work is to investigate the effects of two chemical pre-treatment methods on the water absorption property of polyester-fibre composites. Fully grown kenaf (hibiscus cannabalis) bast fibres were manually retted from the stalk, washed, and cut into short fibre lengths of about 10 cm. One portion of the fibres was pre-treated with 5% pbw NaOH solution before immersing it in glacial acetic acid and then in acetic anhydride. The second portion was pre-treated with 5%pbw of NaOH and 0.125% of KMnO4 in acetone. The third portion of fibres was untreated to serve as control. The ground fibre was incorporated into ortho unsaturated polyester and cast with Teflon square shaped mould. The cured samples were weighed and immersed in water at room temperature until no further gain in weight was observed. The SEM of the fibres and the composites was taken. The results showed that the acetylation pre-treatment method reduced the water absorption property of the composites by a minimum of 46.0% across all fibre volume fractions while the permanganate pre-treatment reduced it by at least 25.5%. Chemical pre-treatment of fibres can therefore


2013 ◽  
Vol 753-755 ◽  
pp. 762-770 ◽  
Author(s):  
Xi Xi He ◽  
Tao Zhang

Solid recycled coarse aggregate concrete bricks were produced by QTY4-40 brick machine with strength grades of MU15-MU30. Recycled aggregate replacement rate was up to 100%. Water absorption and moisture content were tested. Two methods were taken to test the drying shrinkage. The impact of recycled aggregate replacement rate and curing period on the drying shrinkage rate, water absorption, moisture content, density was analyzed, and the relationship between them was presented. The results indicate that recycled aggregate can increase the shrinkage of solid concrete brick. The shrinkage of recycled solid concrete bricks' (fully substitute) is larger than ordinary concrete bricks' by 1.6-2 times. Water reducer is helpful to improve the water retention and decrease the shrinkage of brick. One of the test results of shrinkage got by the methods recommended in relevant specification is smaller.


2022 ◽  
pp. 131-142
Author(s):  
Ahmad A. Khalaf ◽  
Salwa A. Abed ◽  
Saad Sami Alkhfaji ◽  
Mudhar A. Al-Obaidi ◽  
Muammel M. Hanon

Recently, there has been a tendency for scientific studies to deal with natural materials as fillers and reinforcement for polymer composites, which are used in many different applications due to their environmentally friendly properties when compared to synthetic materials. The current study aims to preserve the environment by dealing with natural materials and their influence on the mechanical properties and water absorption property of the polymer composites. In this study, epoxy composites were produced from local natural sourced non-hazardous raw natural materials using grey relational analysis (GRG). The materials used for fabrication include micro-filler of pollen palm 50 μm, seashell 75 μm and epoxy resin. Nine different composites were prepared using pollen palm and seashell as reinforcement material by varying the wt % of the micro-filler. Rule of the mixture was used for formulation and wt % of (0.5, 1 and 1.5) % reinforcement and 99.5, 99 and 98.5 % epoxy (binder) were used for composites. Grey relational analysis was conducted in order to scale the multi-response performance to a single response. The results indicate that optimum performance can be achieved with the addition of 1.5 wt % micro-filler of seashell, which achieved the first rank, while the second rank achieved by 0.5 wt % micro-filler of palm pollen and seashell when compared to other composites. The addition of micro-fillers has improved greatly the mechanical properties of epoxy composites. The loading of micro-fillers has influenced the water absorption property of composites based epoxy in ascending order


2011 ◽  
Vol 250-253 ◽  
pp. 1058-1061
Author(s):  
Zhi Xing Zeng ◽  
Li Xing Su

On the premise of using the five dosage levels of recycled coarse aggregate, the paper primary study on the drying shrinkage and water absorption rate of recycled concrete hollow block in order to determine the maximum dosage of recycled coarse aggregate, then find out the relationship between the drying shrinkage and the water absorption rate of recycled concrete hollow block. The results showed that: the maximum dosage of recycled coarse aggregate can reach 100%; there is a quadratic relationship between the drying shrinkage and the water absorption rate of the block.


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