Research on steel-fibber polymer concrete machine tool structure

Researched on the design and manufacturing of machine tool bed made by Steel-fibber Polymer Concrete(SFPC),which analyzed the static,dynamic and thermal performances of the bed.The results of study prove that machine tool bed made with SFPC is much more superiority than made in cast iron in dynamic and thermal perform- ances,and is more superiority then made in Polymer Concrete (PC) in static perform- ances.It can be concluded that the static,dynamic and thermal properties of machine tool can be improved by manufacturing machine tool bed with SFPC.Also SFPC machine tool bed posses some other advantages in the following: short development time,simple pro- duction process,reducing cost cost,saving energy,iron and steel.

Compressive Performance of Fiber Reinforced Recycled Aggregate Concrete by Basalt Fiber Reinforced Polymer-Polyvinyl Chloride Composite Jackets

The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete.

Exploring the Synergy: Experimental and Theoretical Investigation of Steel and Glass Fiber Reinforced Polymer (GFRP) Reinforced Slab Incorporating Alccofine and M-Sand

Introduction: This study investigates the Experimental and Theoretical Investigation of Steel and Glass Fiber Reinforced Polymer (GFRP) Reinforced Slab Incorporating Alccofine and M-sand. Objective: Specific objectives include evaluating the mechanical properties and structural behaviour of steel and GFRP-reinforced one-way slabs and comparing experimental and theoretical predictions. Methods: Four different mix proportions were arrived at, comprising both conventional concrete and Alccofine-based concrete. In each formulation, a combination of normal river sand and M-sand was utilized. Results: Concrete with Alccofine exhibits superior mechanical properties, while M-sand incorporation minimally affects strength but reduces reliance on natural sand. GFRP-reinforced slabs display distinct brittle behaviour with significant deflections post-cracking, contrasting steel-reinforced slabs’ gradual, ductile failure. Discrepancies between experimental data and design recommendations underscore the need for guideline refinement. Conclusion: Alccofine and M-sand enhance concrete properties, but reinforcement type significantly influences slab behaviour. GFRP-reinforced slabs, though exhibiting lower values than steel, offer advantages in harsh environments, warranting further optimization.

Modification of High Performances of Polymer Cement Concrete

The workability,mechanical and physical properties are investigated,based on the requirements of the high properties of polymer cement concrete (PCC).The research results reveal that PCC is greatly improved and strengthened by adding appropriate polymer.At polymer/cement=0-0.15,its porosity decreases greatly due to the improved pore structure.The weak area at interface is strengthened.The workability,mechanical and physical properties are obviously enhanced with the proportion of polymer and cement.At the same time the properties are much improved under the adequate curing conditions and admixture (0-10%).

Compressive Strength Estimation for the Fiber-Reinforced Polymer (FRP)-Confined Concrete Columns with Different Shapes Using Artificial Neural Networks

An evaluation of existing strength of concrete columns confined with fiber-reinforced polymer( FRP) was presented with extensive collection of experimental data. According to the evaluation results, artificial neural networks( ANNs) model to predict the ultimate strength of FRP confined column with different shapes was proposed. The models had seven inputs including the column length,the tensile strength of the FRP in the hoop direction,the total thickness of FRP,the diameter of the concrete specimen,the elastic modulus of FRP,the corner radius and the concrete compressive strength. The compressive strength of the confined concrete was the output data. The results reveal that the proposed models have good prediction and generalization capacity with acceptable errors.

Influence of Polymer Addition on Performance and Mechanical Properties of Lightweight Aggregate Concrete

The influence of polymer addition on microstructure, performance and mechanical properties of lightweight aggregate concrete was investigated. It was found that the addition of polymer improved the performance and mechanical properties of lightweight aggregate concrete. It was ascertained that the modification of microstructural uniformity and densification with the addition of polymer is responsible for the enhancement of mechanical properties. With respect to compressive strength and bending strength, the lightweight aggregate concrete added with 13% ethylene-acetate ethylene interpolymer (EVA) exhibits preferred mechanical properties. Key words lightweight aggregate concrete - polymer - microstructure - mechanical properties CLC number TU 528.2 Foundation item: Supported by the National Nature Science Foundation of China (50272045)Biography: Jiang Cong-sheng (1963-), male, Ph. D candidate, Associate professor, research direction: advanced architectural materials.

Polymer-modified Concrete with Improved Flexural Toughness and Mechanism Analysis

By selecting different types of polymer mixing into concrete, the toughness of concrete is investigated, and results indicate polymer has obvious effect to improve the toughness of concrete. Microstructure of polymer-modified concrete were studied through environment scanning electron microscope and digital micro-hardness tester, results show that polymer acts as a flexible filler and reinforcement in concrete, and alters the microstructure at mortar and ITZ. By crack path prediction and energy consumption analysis, the crack path of polymer-modified concrete is more tortuous and consumes more energy than that of ordinary concrete.

Shrinkage and Compressive Strength of Concrete with Superabsorbent Polymers

The effects of superabsorbent polymers on the shrinkage and mechanical properties of concrete were investigated.Results of shrinkage tests show that SAP addition reduces the shrinkage.Especially,for the concrete with 3.84 kg SAP/m3 concrete,the shrinkage is little.Compressive strength of concrete with SAP is lower than that of concrete without SAP.However,for the concrete with SAP,the ratio of compressive strength at 90 days to one at 3 days is larger than that of concrete without SAP.

Performance of Steel-fiber Reinforced Concrete Exposed to High Temperature

Effects of high temperature on the compressive and splitting strength of the steel-fiber reinforced concrete (SFRC) with different content of steel-fiber were investigated and its mechanism was simply analyzed.Results indicate that the compressive and splitting strength of SFRC decrease slowly within 400 ℃ and they decay a little faster when over 400 ℃.The residual compressive and splitting strength rate of SFRC (2% fiber) increase about 27.6% and 9.3% of that of the control concrete without steel-fiber,respectively.The finite element software ANSYS was adopted to analyze the temperature field and stress field of the steel-fiber reinforced concrete at 400 ℃.The simulation results can further explain the effects of fiber content on the thermal field and stress field in SFRC and forecast the crack tendency of SFRC during heating process.

Microscopic Characterization of Ecological Concrete Polymeric

The Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) with integrated digital camera are techniques that are used in the present investigation, for the morphological characterization of a new composite material called “organic polymer concrete” in which microparticles added fibers and polyethylene terephthalate (PET) recycling mechanically (RM). Polymer concrete (PC) is a new composite material (MC) in the application considered as an alternative material of construction in which reinforcement particles are recycled polymers which have approximately the same dimensions in all directions. Therefore, the particles can be rods, spheres, chips and many other shapes whose appearance reasons are about 10 microns. These MC, the size, shape and distribution and the ratio and the modulus of the particles affect the properties of the material.

Theoretical study on constitutive relationship of fiber reinforced polymer confined concrete

We proposed a bilinearity constitutive curve model of fiber reinforced polymer(FRP) confined concrete which includes a parabola in the first stage and a straight line in the second stage. The FRP-confined concrete has powerful confinement status and weak confinement status leading to different equations of parabola. We analyzed the impacts of factors such as confinement ratio and restrain stiffness on confined concrete compressive strength,ultimate strain and other control parameters through finite element analysis. The results show that the confinement ratio determines the confinement status,and the increase of the confinement ratio has a limited capacity to increase the compressive strength. The deformation of confined concrete is influenced by restrain stiffness. The stronger the restrain stiffness is,the less the lateral deformation is and the greater ultimate axial strain will be. The consideration of equivalent section coefficient kse is needed in the non-circular section confined concrete. We analyzed the results and proposed boundary values of strong and weak confinement styles,a peak/inflection point stress and strain model,and a compressive strength and ultimate strain model.

Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete （RC） beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer （CFRP） sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with sidebonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in AC1-440 and fib European code were compared with the experimental results.

Carbon Fibre Reinforced Concrete: Dependency of Bond Strength on T_gof Yarn Impregnating Polymer

In this paper, a method for the evaluation of the influence of different polymer suspensions and environmental conditions on adhesion between an impregnated carbon fibre heavy tow and concrete for reinforcement will be proposed. For this purpose, the impregnation material itself was investigated as a polymer film before and after incubation in water and aqueous suspensions, such as NaOH and a cementitious solution, in terms of its thermal properties, swelling behaviour and morphology. Thin polymer films were manufactured and subsequently investigated with quantification of the swelling for 28 d by thermal and scanning electron microscope analysis. The effect of pull-out shear stress was evaluated to investigate parameters such as high temperature and moisture on adhesion to concrete. Contact angle measurements were used to determine the surface energy of the polymer films. All incubated polymer films yielded a change in both surface morphology and specific residues on the polymer film surface, e.g. in the form of calcium carbonate, but no change in glass-transition temperature. A high correlation between glass-transition temperature and measured shear stress was shown during single yarn pull-out tests. Furthermore, the water treatment of pull-out samples strengthened the influence for the glass-transition temperature during the adhesion test. No influence of the surface energy of the used polymer impregnation for carbon fibres on the pull-out test was detected.

Polymer Modified Concrete of Blended Cement and Natural Latex Copolymer: Static and Dynamic Analysis

This paper deals with the effect of blended cement and natural latex copolymer to static and dynamic properties of polymer modified concrete. The polymer was used copolymer of natural latex methacrylate (KOLAM) and copolymer of natural latex styrene (KOLAS) with composition of 1%, 5%, and 10% w/w of weight of blended cement in concrete mixture. They are tested for compressive strength, flexural strength, splitting tensile strength, and modulus elasticity for static analysis, and impact load and energy dissipation profile for dynamic analysis. The result shows that KOLAM with concentration 1% give better performance in static and dynamic properties. The KOLAM 1% gives improvement in flexural strength, splitting tensile strength and modulus elasticity about 4%, 13% and 3% compared to normal concrete. And for dynamic properties, KOLAM 1% could reduce impact load up to 35% and improve energy dissipation capacity about 45% compared to normal concrete. The concentration of KOLAM higher than 1% resulting negative effect to static and dynamic properties, except modulus of elasticity. For KOLAS, there were no positive trends of static and dynamic properties.

Concrete Based on Fly Ash Alumosilicate Polymers

Concretes on the basis of the alumosilicate polymer can be prepared by alkali activation （NaOH, sodium water glass） of waste brown coal fly ash. The preparation is possible： （1） by using a short-term heating of the concrete mix （to 80 ℃）; or （2） by allowing the mix to harden spontaneously at a temperature of 20 ℃. The concretes prepared by short-time heating attain high strength values after their preparation; the values are comparable to those characterizing concretes obtained on the basis of Portland cement. The strength development of concretes hardening at 20 ℃ is substantially less steep but, nevertheless, the strength attained after about 60 days is practically identical with that of the concretes exposed to a short-time heating. The shrinkage of concretes prepared by short-time heating is very small as compared with the concretes allowed to harden spontaneously; the shrinkage of latter concretes is larger than that of the concretes on the basis of Portland cement. The concretes on the basis of alumosilicate polymer exhibit much better resistance to the corrosive action of the environment as compared with those prepared on the basis of Portland cement.

Experimental Study of Concrete Column Shape Modification Using Fiber Reinforced Polymer Composite Shells and Expansive Cement Concrete

Fiber Reinforced Polymer （FRP） composites are an effective material for strengthening circular concrete columns. The effectiveness of FRP confinement for square and rectangular columns is greatly reduced due to stress concentrations at the sharp comers and loss of the membrane effect at the fiat sides of the cross-section. Shape modification can eliminate the effects of column comers and flat sides, and thereby restore the membrane effect and improve the compressive behavior of FRP-confined square and rectangular concrete columns. Shape modification using chemical post-tensioning, achieved by using expansive cement concrete, is described and several mix designs for obtaining the optimal level of expansion are presented. In addition, parametric studies regarding the optimal geometry of the shape-modified cross-section are presented utilizing the analytical model.

Bond Performance of Fiber Reinforced Polymer （FRP） Bars in Autoclaved Aerated Concrete （AAC）

This paper concerns the bond strength of FRP bars in AAC by the concentric pullout test. Specimens were subjected to compare with mild steel bars. The bond performance including the mode of failure and bond strength was investigated with varying embedment length and surface treatment. Regarding the bond performance, embedment depth has influenced on bond strength as well as the sanded surface. Carbon fiber reinforced polymer （CFRP） pronounced the most promising results with the highest bond strength attained.

Investigating Some Parameters Affecting Flexural Behavior of Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforced Polymer Laminate

In this paper,the influence of some important parameters affecting the flexural behavior of reinforced concrete beams strengthened with one layer of carbon fiber reinforced polymer(CFRP)laminate has been studied.For this purpose,six reinforced concrete beams were cast and tested in the laboratory.Based on the obtained data,when CFRP laminate is applied to the tension face,too close to the steel rebar,the flexural strength of the strengthened beam is reduced.In general,the performance of the beam strengthened with one wide CFRP strip is better than that strengthened with two equivalent narrow strips.Ultimate load capacity of each strengthened beam was calculated based on the method given by the ACI 440.2R and compared with the test one.It is concluded that,to avoid the steel rebar-CFRP laminate interaction effect,the CFRP laminate depth-to-the effective depth ratio(df/d)should not be smaller than about 1.17.

Toughness of Polymer Modified Steel Fiber Reinforced Concrete

An experimental investigation is carried out to study the toughness of polymer modified steel fiber reinforced concrete. Volume fraction of steel fibers is varied from 0% to 7% at the interval of 1% by weight of cement. 15% SBR latex polymer was used by weight of cement. Cubes of size 150 × 150 × 150 mm for compressive strength, prism specimens of size 150 mm × 150 mm × 700 mm for flexure strength and, specimen of size 150 × 150 × 150 mm with 16 mm diameter tor steel bar of length 650 mm embedded in concrete cube at the center for bond test were prepared. Various specimens were tested after 28 days of curing. Area under curve (toughness) is measured and mentioned in this work.

Impact of Polymer Coating on the Flexural Strength and Deflection Characteristics of Fiber-Reinforced Concrete Beams

Liquid polymers(LP)have become an important structural material used in the construction industry in the last decade.This paper investigates the via­bility of using commercially available LPs as a coating material to improve the flexural strength of fiber-modified concrete beams.The scope included preparing rectangular prism concrete beams with a concrete mixture includ­ing fly ash and fiber and coating them with four different liquid polymers at a uniform thickness following the curing process while one set of sam­ples was maintained under the same conditions as a control group without coating.In addition,cylindrical samples were prepared to determine the compressive strength of the concrete mixture.Following the curing process in an unconfined open-air laboratory environment for another 28 days,con­crete samples were tested to determine the flexural strength and deflection characteristics under center point loading equipment.The results revealed that all four coating types enhanced both the flexural strength and the av­erage maximum deflection of the beams compared to the control group.While the enhancement in the flexural strength changed approximately between 5%and 36%depending on the coating type,the improvements in average maximum deflections varied between 3.7%and 28.4%.