Effect of micro silica on fiber-reinforced self-compacting composites containing ceramic waste

2020 ◽  
Vol 55 (1) ◽  
pp. 95-107
Author(s):  
Alireza Mansoori ◽  
Mohammad Mohtasham Moein ◽  
Ehsan Mohseni

This paper aims to evaluate the impact of ceramic waste powder (CWP), micro silica (MS) and steel fiber (SF) on self-compacting mortar. CWP at ratios of 10 and 20%, and MS at 1 and 5% by weight of cement were replaced the cement. Beside, SF was added at ratios of 0.5 and 1% of cement. Mini slump flow diameter and mini V-funnel flow time tests were carried out to determine the workability of fresh composites. Compressive strength, flexural strength, water absorption, electrical resistivity and drying shrinkage tests were performed on hardened mortars. Scanning electron microscope (SEM) technique was employed to assess the microstructure. The results indicated that CWP reduced the mechanical properties by about 20% and increased permeability by about 14%. However, inclusion of micro silica particles improved the properties outstandingly. Compressive strength increased about 30% by inclusion of MS. It was also observed that the addition of fibers from 0.5% to 1% increased the flexural strength. This improvement was more obvious in samples with higher contents of micro silica. It can be reported that by including the both micro silica and steel fibers, the bonding between the cement paste and fibers was developed. Replacement of micro silica led to increase of electrical resistivity by about 99% in samples containing 20% ceramic waste powder. The microstructure studies confirmed the significant increase of density and uniformity of the hydration products in the presence of micro silica particles.

2010 ◽  
Vol 150-151 ◽  
pp. 779-782
Author(s):  
Qing Xin Zhao ◽  
Zhao Yang Liu ◽  
Jin Rui Zhang ◽  
Ran Ran Zhao

By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.


2014 ◽  
Vol 919-921 ◽  
pp. 1974-1978
Author(s):  
Mei Yan Hang ◽  
Cheng Xiao Sun ◽  
Pei Yu Zhang

The article studies the impact of steel fiber on the performance of lightweight aggregate concrete,including compressive strength, flexural strength, modulus of elasticity and impact toughness. The experimental studies show that steel fiber has little effect on the compressive strength of lightweight aggregate concrete, however, it can improve the pattern obviously. With the increasing of steel fiber content, the flexural strength and impact toughness of concrete increases. With the increasing of steel fiber content ,the elastic modulus of concrete also increases. The studies of this paper provide a certain technical references with the future research of steel fiber reinforced lightweight aggregate concrete.


Author(s):  
Nguyen Van Chinh

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.


2011 ◽  
Vol 399-401 ◽  
pp. 1214-1217 ◽  
Author(s):  
Xin Gang Yu ◽  
Yan Na Gao ◽  
Lin Lin ◽  
Fang Li

Lightweight concrete has been used for structural purposes for many years and it is developed very fast in resent years due to its lightweight and favourable for insulation properties. High strength foam concrete is a fairly new kind of lightweight concrete with excellent properties of outstanding workability, low density and high strength. Responsible for these properties are the macro-, meso- and micro- porosity of the foam concrete which are mainly affected by the foaming agent. The influence of foaming agent’s dilution ratio and foam dosage on the fluidity, compressive strength, flexural strength and drying shrinkage of high density foam concrete designed for structural materials is investigated in this paper.


2011 ◽  
Vol 374-377 ◽  
pp. 1619-1622
Author(s):  
Ling Zhang ◽  
Zhi Qiang Shi

In this article, based on a certain actual project, the main physical and mechanical performance including compressive strength, splitting strength, flexural strength and shear strength are studied in detail through the experiments. Different fiber types and volume ratio are chosen in the experiments for the purpose of determining the best quantities and types of steel fiber in concrete to lengthen the service life of deck pavements. It is showed that the research has some referential value for similar projects.


2010 ◽  
Vol 168-170 ◽  
pp. 456-459
Author(s):  
Hai Yan Yuan ◽  
Shui Zhang ◽  
Guo Zhong Li

By adopting the method of orthogonal experimental design, the effect of three independent variables, that is steel fiber fraction, polypropylene fiber fraction and silica fume fraction on the compressive strength, flexural strength and shrinkage of cement mortar was studied. The results indicate that steel fiber is one of the most important factors affecting compressive strength and shrinkage, and polypropylene fiber is one of the most important factors affecting flexural strength and shrinkage of cement mortar. By using deviation analysis to analyze the orthogonal experiment results, the optimized mix proportion of hybrid fiber reinforced cement mortar is determined. The hybrid effect of steel fiber and polypropylene fiber on the properties of cement mortar is discussed.


2021 ◽  
Author(s):  
Gude Reddy Babu ◽  
Pala Gireesh Kumar ◽  
Nelluru Venkata Ramana ◽  
Bhumireddy Madhusudana Reddy

The present examination illustrates the impact on the hardened and fresh cement mortar and cement with the inclusion of nanosilica of size 40 nm in various environmental conditions (UltraTech, India). It is quite notified that an elevation in compressive strength as well as flexural strength along with an improvisation in the performance and life span of cement mortar. The samples of M5 grade blended with a ninety percentage of concrete and remaining with nanosilica was identified to have a finer working elevation in as well as in standards when collated with the conventional cement mortar. The corollary of hardened and fresh cement, strength parameters were looked upon with the aid of XRD (X-ray Diffraction). Also, the SEM (Scanning Electron Microscope) test holds a predominant role in analysis.


2017 ◽  
Vol 25 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
Cheng-Hao Li

The repair of damaged structures is a complicated problem in the construction industry and it is no uniform standard for evaluating the effectiveness of repair materials. Two different redispersible polymer powders, ethylene vinyl acetate (EVA) and polyvinyl acetate-vinyl carboxylate (VA/VeoVa), were added in the repair mortars with two water-cement ratios and three polymer-cement ratios. The effectiveness of repair materials was evaluated according to the physical, mechanical properties and micrographs. Testing program includes setting time, drying shrinkage, thermal expansion, compressive strength, tensile strength, flexural strength, bond strength, X-ray diffraction analysis, scanning electron microscopy observation. Test results show that the specimens with VA/VeoVa and w/c of 0.5 have highest compressive strength, tensile strength, flexural strength and bond strength. The specimen with EVA also has higher strength than control one at the age of 28 days. The drying shrinkage deformation of VA/VeoVa specimen is close to the control one. The specimens with VA/VeoVa have lower thermal expansion than EVA specimen when the water-cement ratio is 0.5 and there is no difference between EVA and VA/VeoVa specimens for the water-cement ratio of 0.6. The micrographs show that adding polymer powder can reduce the pore and improve the durability.


2021 ◽  
Vol 47 (1) ◽  
pp. 56-60
Author(s):  
Kamel Al-Zboon ◽  
Talal Masoud

Huge amounts of stone cutting waste are generated annually posing a heavy environmental load on nature and resulting in economic challenge to the plants' owners. The conducted researches in this field showed that stone, marble and granite waste could be reused in many applications. This paper aims to investigate the possible application of stone cutting waste in the construction sector. Review process includes investigation of the conducted researches, outcomes of the performed projects, and the impact of this waste on the characteristics of concrete compressive strength, flexural strength, splitting strength, concrete workability, bricks strength, terrazzo tile strength and soil properties. The results revealed that at suitable substitution ratio, this waste can increase the compressive strength of concrete up to 21%, the flexural strength by 33% and splitting strength by 4.3%. In contrast, the compressive strength of bricks decreased by up to 67% at replacement ratio of 100%, and the transverse strength of tiles decreased up to 18% at replacement ratio of 50%. Replacement of soil with stone cutting waste resulted in an improvement in the characteristics of cohesive and sandy soil. Concrete workability decreased significantly with replacement of normal aggregate with stone cutting waste. Such results buttressed the feasibility of reusing this material in the construction sector, which reduces the cost of storage and disposal, and creates a nonconventional income.


2016 ◽  
Vol 10 (5) ◽  
pp. 194
Author(s):  
Rouholla Barati ◽  
Seyed Ali Sahaf ◽  
Mehdi Jamshidi ◽  
Alireza Razazpor

<p>Roller compacted concrete pavement (RCCP) is one of the different types of concrete pavements which is considered as a new developing technology due to its rapid installation. However, RCCP is difficult to install in high thickness; therefore, it is essential to reduce the thickness of pavement while maintaining strength. Flexural strength and fatigue resistance are the most important parameters effective on design of thick pavements. These parameters are directly related to uniaxial compressive strength of concrete. Hence, this study determines and evaluates the compressive strength of 7-day and 28-day specimens. Given the durability of concrete pavements, particularly their penetrability against water, corrosive materials and minerals, the most important parameter is to reduce water absorption of RCCP. In order to increase strength and reduce water absorption of RCCP, different additives as well as a proper mix design can be significantly effective. This study examines the effect of various mix designs and different percentages of micro silica gel on RCCP. The suggested mix design is continuous aggregation and addition of 7% micro silica gel, which increases strength and durability of RCCP.</p>


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