The Inhibitory Effect of Polypropylene Fibers towards the Shrinkage of Cement Based Material

2015 ◽  
Vol 744-746 ◽  
pp. 1531-1534
Author(s):  
Hua Yuan ◽  
Yun Hua Li

At present, polymers, fiber and other additives are added to the cement based materials by researchers at home and abroad for the purpose of dealing with the difficult problems occur in practical application, such as low tensile strength, small ultimate elongation, remarkable brittleness, easy to crack and other issues. In this paper, the shrinkage deformation of cement based materials are classified into four types upon the analysis of shrinkage reasons, then the inhibitory effect and its mechanism of polymers fiber for cement based material are investigated.

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 413 ◽  
Author(s):  
Ren ◽  
Chen ◽  
Ye ◽  
Su ◽  
Xiao ◽  
...  

In order to reduce the usage amount of pesticide fertilizers and protect the natural environment, seed coating agents are receiving increased wide concern. In this study, the active constituent (pesticide) and inactive components (surfactants and film former) of the seed coating agents were screened and optimized by the wet sand processing superfine grinding method. The fungal inhibition test of pesticides showed that thifluzamide, fludioxonil, pyraclostrobin, and difenoconazole have an obvious fungal inhibitory effect on wheat sharp eyespot, take-all, and root rot. LAE-9 and polyacrylamide + carboxymethyl cellulose (CMC) is recommended for the safe surfactant and film former, respectively, based on the seed germination test. Moreover, 6% difenoconazole · fludioxonil flowable concentrate for seed coating (FSC) stimulates the seedling growth of wheat, advances the growth of root, and improves biomass in the field trial, meanwhile, the control efficiency reached above 80%. Thus, we suggested it can be used as an effective seed coating agent for the control of soil-borne diseases in wheat. The seed coating agent has the characteristics of disease prevention, increasing crop yield, and safety of environment, which is of significance in practical application.


2020 ◽  
Vol 175 ◽  
pp. 11014
Author(s):  
Jian Sun ◽  
Andrii Bieliatynskyi ◽  
Kateryna Krayushkina ◽  
Oleksandra Akmaldinova

Steel slag asphalt concrete is one of the important components of asphalt concrete. There are some differences between the steel slag asphalt concrete and ordinary asphalt concrete. Based on the research of scholars at home and abroad, this paper systematically introduces the steel slag characteristics and excellent performance of steel slag asphalt concrete, summarizes the problems existing in the practical application of steel slag asphalt concrete, and provides references for its promotion and application.


2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Chen-chen Fan ◽  
Qian Tang

This paper aims to develop a modified animal glue sand binder for foundry casting with improved water resistance and bonding strength. An efficient method is reported by using sodium hydroxide as the catalyst to improve the operability of animal glue binder and allyl glycidyl ether as the modifier to improve the water resistance and bonding strength. Sand specimens prepared using allyl glycidyl ether-modified animal glue binder were cured by compressed air at room temperature. The proposed method saves energy and is environmentally friendly and inexpensive. Compared with unmodified animal glue binder, standard dog bone sand specimens with allyl glycidyl ether-modified animal glue binder had higher tensile strength of 2.58 MPa, flowability of 1.95 g, better water resistance (a lower decrease in tensile strength at 25 °C and relative humidity of 60%), and good collapsibility. This allyl glycidyl ether-modified animal glue binder is suitable for practical application in the foundry industry.


Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1827 ◽  
Author(s):  
Marcin Małek ◽  
Mateusz Jackowski ◽  
Waldemar Łasica ◽  
Marta Kadela

High-performance concrete has low tensile strength and brittle failure. In order to improve these properties of unreinforced concrete, the effects of adding recycled polypropylene fibers on the mechanical properties of concrete were investigated. The polypropylene fibers used were made from recycled plastic packaging for environmental reasons (long degradation time). The compressive, flexural and split tensile strengths after 1, 7, 14 and 28 days were tested. Moreover, the initial and final binding times were determined. This experimental work has included three different contents (0.5, 1.0 and 1.5 wt.% of cement) for two types of recycled polypropylene fibers. The addition of fibers improves the properties of concrete. The highest values of mechanical properties were obtained for concrete with 1.0% of polypropylene fibers for each type of fiber. The obtained effect of an increase in mechanical properties with the addition of recycled fibers compared to unreinforced concrete is unexpected and unparalleled for polypropylene fiber-reinforced concrete (69.7% and 39.4% increase in compressive strength for green polypropylene fiber (PPG) and white polypropylene fiber (PPW) respectively, 276.0% and 162.4% increase in flexural strength for PPG and PPW respectively, and 269.4% and 254.2% increase in split tensile strength for PPG and PPW respectively).


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 640 ◽  
Author(s):  
Hui Wei ◽  
Tao Wu ◽  
Xue Yang

The impact of carbon and polypropylene fibers in both single and hybrid forms on the properties of lightweight aggregate concrete (LWAC), including the slump, density, segregation resistance, compressive strength, splitting tensile strength, flexural strength, and compressive stress–strain behavior, were experimentally investigated. The toughness ratio and ductility index were introduced for quantitatively evaluating the energy-absorbing capacity and post-peak ductility. A positive synergistic effect of hybrid carbon and polypropylene fibers was obtained in terms of higher tensile strength, toughness, and ductility. The toughness ratio and ductility index of hybrid fiber-reinforced LWAC were increased by 26%–37% and 12%–27% compared with plain LWAC, respectively. The fiber in both single and hybrid forms had a smaller effect on the linearity ascending branch of the stress–strain curves, whereas the post-peak patterns in terms of the toughness and ductility for the hybrid fiber-reinforced LWAC were significantly improved when the fiber in hybrid form.


1961 ◽  
Vol 34 (3) ◽  
pp. 897-909
Author(s):  
Thor L. Smith ◽  
Paul J. Stedry

Abstract A study was made previously of the temperature and strain rate dependence of the stress at break (tensile strength) and the ultimate elongation of an unfilled SBR rubber. In that study, stress-strain curves to the point of rupture were measured with an Instron tensile tester on ring type specimens at 14 temperatures between −67.8° and 93.3° C, and at 11 strain rates between 0.158×10−3 and 0.158 sec−1 at most temperatures. The tensile strength was found to increase with both increasing strain rate and decreasing temperature. At all temperatures above −34.4° C, the ultimate elongation was likewise found to increase with increasing strain rate and decreasing temperature but at lower temperatures the opposite dependence on rate was observed; at −34.4° C, the ultimate elongation passed through a maximum with increasing rate.


2014 ◽  
Vol 590 ◽  
pp. 312-315
Author(s):  
Wei Hong Xuan ◽  
Pan Xiu Wang ◽  
Yu Zhi Chen ◽  
Xiao Hong Chen

The dry shrinkage deformation of polypropylene fiber mortar was analyzed by ANSYS software and compared with experiment value in this paper. The error of the calculated and experimental results in the 14 days and 28 days are 7.8% and 10.5%. It can be found that the calculated results are in good agreement with test results. The results indicate that the dry shrinkage value of polypropylene fiber mortar is lower than ordinary mortar. Adding polypropylene fibers can inhibit the process of cracking and improve the fracture toughness of cement-based materials.


2012 ◽  
Vol 430-432 ◽  
pp. 1064-1067
Author(s):  
Yu Zhi Chen ◽  
Wei Hong Xuan ◽  
Xiao Hong Chen

The effect of the different addition amounts of polypropylene fibers on the basic mechanical properties of concrete were investigated in this paper. The results show that the flexural tensile strength of concrete changed slightly after adding low-dosage polypropylene fiber(0.04%~0.16%); Axial compressive strength and flexural tension modulus decreased, limiting flexural strain increased gradually with the amounts of fibers rising.


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