Impermeability of Wet-Sieving Fine Aggregate Concrete Made from Ordinary Concrete

2011 ◽  
Vol 201-203 ◽  
pp. 2883-2886
Author(s):  
Xiao Ke Li ◽  
Shan Zhao ◽  
Li Sun ◽  
Shun Bo Zhao
Keyword(s):  
Reinforced Concrete ◽  
Chloride Ion ◽  
Fine Aggregate ◽  
Ion Diffusion ◽  
Aggregate Concrete ◽  
Structural Wall ◽  
Water Permeation ◽  
Ordinary Concrete ◽  
Concrete Layer ◽  
Wet Sieving

The research is part of wet-sieving concrete technique for building thermal insulated reinforced concrete composite wall. The fine aggregate concrete is made from ordinary concrete passing sieve with square mash of 15 mm for casting surface concrete layer of the wall, the recomposed concrete is made of residual concrete stayed on sieve and ordinary concrete for casting reinforced concrete structural wall. The impermeability of fine aggregate concrete and recomposed concrete are measured by water permeation method and chloride-ion permeation method, the relative permeability and chloride-ion diffusion coefficients of concrete are determined. Based on the test, the effects of the changes of aggregate series, sand ratio and cement paste on the impermeability of concrete are analyzed.

Experimental Study on Mechanical Properties of Fine Aggregate Concrete Made after Wet-Sieving Coarse Aggregate

2010 ◽  
Vol 168-170 ◽  
pp. 2200-2203 ◽  
Author(s):  
Shun Bo Zhao ◽  
Na Liang ◽  
Li Xin Liu ◽  
Li Sun ◽  
Su Yang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Fine Aggregate ◽  
Concrete Wall ◽  
Aggregate Concrete ◽  
Structural Wall ◽  
Ordinary Concrete ◽  
Reinforced Composite ◽  
Wet Sieving

The validity of the wet-sieving concrete technique for building the reinforced composite concrete wall are demonstrated in the paper. The fine aggregate concrete made by ordinary concrete passing the sieve with square mash of 15 mm was cast for the surface layer, the recomposed concrete mixed by the residual concrete stayed on the sieve with the ordinary concrete was cast for the reinforced concrete structural wall. The mechanical properties such as the cubic and compressive strengths, the elastic modulus and the splitting and flexural tensile strengths of the fine aggregate concrete, the recomposed concrete and the ordinary concrete were tested and analyzed. The results show that the elastic modulus and splitting tensile strength of fine aggregate concrete reduce in some extent compared with that of ordinary concrete, the mechanical properties of recomposed concrete are almost the same as that of ordinary concrete.

Experimental Study on Shrinkage of Wet-Sieving Fine Aggregate Concrete Made from Ordinary Concrete

2011 ◽  
Vol 197-198 ◽  
pp. 915-918
Author(s):  
Shun Bo Zhao ◽  
Shan Zhao ◽  
Su Yang ◽  
Xiao Lu Ma ◽  
Li Sun
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Fine Aggregate ◽  
Test Results ◽  
Casting Surface ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Concrete Layer ◽  
Composite Wall ◽  
Wet Sieving

The research is part of wet-sieving concrete technique for building thermal insulated reinforced concrete composite wall. The fine aggregate concrete is made from ordinary concrete passing sieve with square mash of 15 mm for casting surface concrete layer of the wall. Tests were conducted to determine drying shrinkage and autogenous shrinkage of fine aggregate concrete and ordinary concrete. On the basis of test results, the variations of these shrinkages are analyzed. It shows that the shrinkage is almost resulted from drying shrinkage; the drying shrinkages of fine aggregate concrete and ordinary concrete increase rapidly in the early ages before 14 d, the former takes place with large value 1.61 times of the later; the increments of drying shrinkage of fine aggregate concrete and ordinary concrete are almost the same after 14 d. The drying shrinkage of fine aggregate concrete is about 1.23 times of ordinary concrete. The formulas are proposed for calculating the drying shrinkage of fine aggregate concrete and ordinary concrete.

Experiment of Carbonization for Wet-Sieving Fine Aggregate Concrete Made from Ordinary Concrete

2011 ◽  
Vol 201-203 ◽  
pp. 2887-2890
Author(s):  
Shun Bo Zhao ◽  
Na Liang ◽  
Xiao Lu Ma ◽  
Su Yang
Keyword(s):  
Grain Size ◽  
Coarse Aggregate ◽  
Cement Content ◽  
Standard Test ◽  
Test Method ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Composite Wall ◽  
Wet Sieving

The research in this paper is part of wet-sieving concrete technique for building thermal insulated reinforced concrete composite wall. The carbonized depths of fine aggregate concrete and ordinary concrete were measured by the carbonization test method. Based on the test, in standard test environmental conditions, the carbonization changes of fine aggregate concrete rely on its inherent combination changes. The lower carbonized depth takes place in fine aggregate concrete comparing with ordinary concrete, which is resulted from the increasing cement content and the reduction of grain size of coarse aggregate in fine aggregate concrete. Finally, the carbonization of fine aggregate concrete is evaluated according to the relative specification, and the reasonable service life of fine aggregate concrete is precast.

Structure Characteristics and Mechanical Properties of Fiber Reinforced Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1556-1560
Author(s):  
Wen Qin Deng ◽  
Jing Zhao
Keyword(s):  
Reinforced Concrete ◽  
Glass Fiber ◽  
Polypropylene Fiber ◽  
Basalt Fiber ◽  
Chloride Ion ◽  
Sem Analysis ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Ion Diffusion ◽  
Glass Fiber Reinforced

Mechanical properties of fiber reinforced concrete with polypropylene fiber, alkali-resistant glass fiber and basalt fiber separately were studied in this paper. The internal structure of fiber reinforced concrete was researched by testing chloride ion diffusion coefficient and scanning electron microscope (SEM) analysis. The results show that adding a certain amount of three fibers separately into concrete have all increased splitting strength. Compared with referenced concrete, compressive strength of alkali-resistant glass fiber reinforced concrete and basalt fiber reinforced concrete are both improved. According to analysis, the effect of srengthening and toughening for basalt fiber is particularly significant. The order of chloride ion diffusion coefficient from lower to higher is alkali-resistant glass fiber reinforced concrete, referenced concrete, basalt fiber reinforced concrete, polypropylene fiber reinforced concrete. This result indicates that alkali-resistant glass fiber bonds cement paste best and makes internal structure densest by SEM analysis.

scholarly journals Call for papers on special issue “Performance-based Service Life Design of reinforced recycled aggregate concrete”

2020 ◽  
Vol 2 (1) ◽  
pp. 045-045
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Chloride Ion ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Special Issue ◽  
Aggregate Concrete ◽  
Service Life Design ◽  
Life Design

Aim & Scope: Sustainability requires a judicious use of natural resources. Reducing the consumption of natural aggregates and ensuring adequate durability of reinforced concrete infrastructures are major steps towards sustainability. Performance-based Service Life Design and recycled aggregate concrete are intense research fields. Considering the research maturity of each subject on its own, it is time to couple them and deliver knowledge on performance-based Service Life Design for reinforced concrete structures incorporating recycled aggregates. This Special Issue of Materials International constitutes a way to disseminate results and findings from original studies, experimental programs, empirical, analytical and numerical modelling of initiation period (carbonation- and chloride ion-related), propagation period or both (service life). Probabilistic, semi-probabilistic and deterministic approaches are welcome.

scholarly journals Shear Capacity and Behaviour of Bending Reinforced Concrete Beams Made of Steel Fibre-Reinforced Waste Sand Concrete

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2996
Author(s):  
Marek Lehmann ◽  
Wiesława Głodkowska
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Fibre Composite ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Fine Aggregate ◽  
Steel Fibres ◽  
Ordinary Concrete ◽  
Model Code ◽  
Model Code 2010

Inthis paper, we report the results of our research on reinforced concrete beams made of fine aggregate fibre composite, with the addition of steel fibres at 1.2% of the composite volume. The fine aggregate fibre composite is a novel construction material, in which the aggregate used is a post-production waste. Twenty reinforced concrete beams with varying degree of shear reinforcement, in the form of stirrups with and without the addition of steel fibres, tested under loading. The shear capacity results of reinforced concrete beams made of the fine aggregate fibre composite being bent by a transversal force, as well as the cracking forces causing the appearance of the first diagonal crack, are discussed. The stages of functioning of such elements are described. Furthermore, the effect of the steel fibres on the reduction of diagonal cracking is analysed. Computation of the shear capacity of the tested elements is performed, based on the Model Code 2010 and RILEM TC-162 TDF standards, for two variants of the compression strut inclination angle θ that measured during testing, and the minimum(in accordance with the Model Code 2010 standard). We found that the SMCFT method part of Model Code 2010 showed the best compatibility with the experimental results. The tests and analyses performed demonstrate that the developed novel fibrecomposite—the properties of which are close to, or better than, those of the ordinary concrete—can be used successfully for the manufacturing of construction elements in the shear capacity aspect. The developed fine aggregate fibrecomposite could serve, in some applications, as an alternative to ordinary concrete.

scholarly journals Structural Behavior of Reinforced Concrete Slabs Containing Fine Waste Aggregates of Polyvinyl Chloride

Buildings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Nisreen S. Mohammed ◽  
Bashar Abid Hamza ◽  
Najla’a H. AL-Shareef ◽  
Husam H. Hussein
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Waste Materials ◽  
Concrete Slabs ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Flexural Performance ◽  
Reinforced Concrete Slabs ◽  
Concrete Mix

In several areas worldwide, the high cost and shortage of natural resources have encouraged researchers and engineers to explore the serviceability and feasibility of using recycled aggregates in concrete mixtures, substituting a normal aggregate percentage. This technique has advantages for the environment by reducing the accumulation of waste materials, while it impacts the fresh and hardened concrete performances, reducing workability, flexural strength, compressive strength, and tensile strength. However, most studies have investigated the influence of replacing normal aggregates with waste aggregates on the concrete mechanical properties without examining the impact of using waste materials on concrete structural performance. The aim of this research is to investigate the effect of replacing 75% of sand volume with polyvinyl chloride (PVC) fine waste aggregates on the performance of reinforced concrete slabs. Different thicknesses of the concrete layer (0%, 25%, 50%, and 100% of slab thickness) containing PVC fine waste aggregates are investigated. Based on the reductions in the toughness and flexural strength capacity due to incorporating 75% PVC fine aggregate dosage, two approaches are used to strengthen the slabs with 75% PVC fine aggregates. The first approach is adding polyvinyl alcohol (PVA) to the PVC fine aggregate concrete mix to improve the mechanical properties of the concrete. The PVA increases the water viscosity in the concrete, which reduces the dry out phenomenon. With that said, the PVA modified fresh concrete does enable the use of the limits of the PVC fine aggregate dosage for high dosage plastic aggregate concrete. The second approach uses two fiber wire mesh layers as an additional reinforcement in the tested slab. Results show that the PVC-30 slab exhibits an 8% decrease in total area toughness compared to the control (Con) slab, while for PVC-60 slab toughness, the total area shows 26% less. Additionally, the inclusion of PVA in the concrete with 75% PVC plastic waste fine aggregate replacement greatly influences the pre-and post-cracking ductile performance among other slabs, representing that using PVA with higher contents might increase the flexural performance. Therefore, due to the substantial effect of PVA material on the concrete flexural performance, it is proposed to utilize PVA with an optimum PCV fine aggregate dosage in the concrete mix.

Durability of Concrete for Thermal Insulation Composite Wall

2013 ◽  
Vol 438-439 ◽  
pp. 314-317
Author(s):  
Feng Lan Li ◽  
Hai Na Chen ◽  
Xue Zhen Feng ◽  
Su Yang
Keyword(s):  
Thermal Insulation ◽  
Coarse Aggregate ◽  
Cement Mortar ◽  
Chloride Penetration ◽  
Fine Aggregate ◽  
Volume Percent ◽  
Water Penetration ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Composite Wall

Tests were carried out to study the durability of fine aggregate concrete and composite concrete simultaneously provided by the wet-sieving technique for the thermal insulation composite wall as building envelops. The workability of every concrete satisfied the basic requirement of cast quality. The composition analyses of concrete showed that compared with the ordinary concrete, the volume percent of coarse aggregate was increased and the volume percent of cement mortar was decreased due to that the residual coarse aggregate stayed on the sieve was blended with ordinary concrete, which increased the resistances of composite concrete to chloride penetration, water penetration and carbonization. Meanwhile, the resistances of fine aggregate concrete to chloride penetration, water penetration and carbonization were reduced due to the obvious increase of the volume percent of cement mortar.

Influence of Quality and Replacement Rate of Recycled Coarse Aggregate on the Frost Resistance of Recycled Concrete

2017 ◽  
Vol 898 ◽  
pp. 2046-2049 ◽  
Author(s):  
Gong Bing Yue ◽  
Qiu Yi Li ◽  
Jian Lin Luo ◽  
Yuan Xin Guo
Keyword(s):  
Frost Resistance ◽  
Coarse Aggregate ◽  
Mass Loss Rate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Recycled Coarse Aggregate

Compared with natural aggregate, the content of hardening cement in recycled aggregate is larger, which leads that the water absorption of recycled aggregate is larger and its performance such as robustness is poorer. And the engineering field pays much attention to the problem of the recycled fine aggregate which can be used in the durability requirements of recycled concrete or not. Using the method of fast freezing and thawing the influence of quality and replacement ratio of recycled coarse aggregate on the frost resistance of recycled concrete was researched basing on ordinary concrete frost resistance performance. The results showed that, in terms of the frost resistance capacity, the order is in: ordinary concrete>high-quality recycled coarse aggregate concrete>normal quality recycled coarse aggregate concrete. After 250 freeze-thaw cycles, the mass loss rate of general quality recycled coarse aggregate concrete is 5%, relative dynamic elastic modulus is 60% when replace rate was 100%.

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