Reactive Powder Concrete Slabs Research Articles

Residual strength capacity of reinforced reactive powder concrete two-way slabs subjected to drop weight

This paper presents an experimental investigation of the effect of the impact force on the residual strength capacity of simply supported reactive powder slabs. Eight specimens of reinforced reactive powder concrete slabs with dimensions of 500 x 500 mm and 70 mm in four categories were used. The influences of slab compressive strength (conventional concrete and reactive powder concrete), steel fiber proportion (1, 1.5, and 2%), percentage of reinforcement in the tension zone (ρ1=0.007, ρ2=0.011, ρ3=0.0179), and the number of impacts (two impacts, four impacts, and six impacts) were all investigated in this test. Investigations were carried out to ascertain each slab's residual response, including first cracking load, residual failure load, residual steel reinforcement strain, maximum central deflection, and crack pattern. The results showed that using reactive powder concrete instead of normal concrete increased the mechanical properties of concrete and resulted in a significant increase in failure load. In addition, the central deflection and strain increased. Increasing the reinforcement ratio increased the failure load while simultaneously decreasing the deflection due to the improvement in slab moment resistance. Furthermore, it was discovered through experiments that the addition of steel fiber to the mixture enhanced the slab’s post-cracking reactivity. The presence of steel fiber raised the slab strength resistance by 21.63% as the steel fiber ratio increased from 1% to 2%. This is because the addition of steel fiber increased the slab's tension resistance.

Punching Strength of Reactive Powder Reinforced Concrete Flat Slabs

This research is devoted to investigating experimentally the punching shear strength of reactive powder concrete slabs under monotonic loading. All slabs have the same flexural reinforcement and same dimensions (1000mm length,600mm width,50mm thickness). The experimental program includes casting and testing of sixteen slabs tested under monotonic loading. The major parameters adopted in the current research include the shape of column (circle, square), column size (twocolumn sizes), number of columns (one, two), and the distance between two columns (3d,5d,7d). Results showed that, the slabs with circular column sections have slightly higher ultimate load than those with square column sections. An increasing column area increases the load of punching shear failure. It was found that the ultimate failure load for slabs with two columns is greater than the slabs with one column. Related to the effect of distance between the two columns for monotonic, it was found that the slabs maximum load reaches the maximum value at distance between the two columns equal to(7d) for a circular section with a diameter of 85mm and 113mm and square section with dimensions of (100*100)mm. While the maximum failure load reaches the maximum value when the distance between two columns (d) for a square section with the dimension of (75*75)mm. Related to the crack patterns, it was noticed that for slabs with larger columns sections with the distance between columns equal to 7d, the failure zone extended (in a large direction) to the slab sides.

Study on leaching damage mechanism of calcium ions of reactive powder concrete (RPC) under ion corrosion

The damage of dissolution and leaching of calcium ions caused by ion corrosion to the macroscopic mechanical properties of RPC is investigated, and the microscopic mechanism of ion corrosion is revealed. Through the unconfined compression test, the effects of different ion corrosion types on the unconfined compression strength (UCS) and failure morphology of RPC, and standard cement mortar (SCM) were studied. The effect of ion corrosion on the micro-structure and element ratio of hydration products was analyzed by SEM/EDS. In addition, through the calcium leaching model test, the effect of NaCl and MgSO4 corrosion on calcium dissolution and destruction of RPC slabs was studied, and the composition of the precipitate was determined by XRD analysis method. A damage constitutive model of RPC with ion corrosion and loading coupling was established, providing a theoretical basis for calculating the ion corrosion depth. The results show that RPC has better resistance to the damage of calcium leaching caused by ion corrosion than SCM. After 90 days of chloride ion and sulfate ion corrosion, calcium precipitation and recrystallization appeared on the surface of RPC, where an insoluble substance formed, and the ion corrosion depth was 13.32 mm and 11.30 mm, respectively.

Behavior of Reactive Powder Concrete Slab with Smeared Reinforcement under Impact Load

This research focuses on studing the main points that concern on the behavior of reactive powder concrete (RPC) slab reinforced by smeared steel fibers subjected to impact load. The rectangular pulse force is used to represent an impact load. The material properties of the reactive powder concrete with the smeared reinforcement are simulated in the range of elastic behavior. The numerical modeling of the RPC slab structure with smeared steel fibers reinforcement is implemented by using ANSYS-LS-DYNA-software. The mode shapes and frequencies values of the RPC slab model are extracted by modal analysis. Impact load analysis of the RPC slab model with smeared steel fibers reinforcement is carried out for different cases. The effect of different amounts of smeared reinforcement and different locations of impact load are investigated. The results show that the first mode shape is governing impact load problems. Also, the effect of smeared reinforcement is so small within elastic range. In addition, it is observed there is a simple ratio between amount of smeared reinforcement and maximum displacement in force vibration.

Performance of Self-Compacted Reactive Powder Concrete Slab Under Harmonic Dynamic Loading

Many types of loading the structure must sustain in addition to dead and live loads according to the function of structural element type that must be taken in analysis. Dynamic resistance to loading of reinforced concrete slabs using self-compact reactive powder concrete, with different boundary conditions at the sides in addition of static loading was studied. The reinforced concrete slabs were designed under static load according to ACI-318R-2014 and then the adequacy was checked under harmonic dynamic loading. The static loading consists of dead load and residential live load considering according to ASCE-07-2010. Modeling analysis was performed to determine the eigenvalues and eigenvectors values and then frequency response analyses of the slab by finite elements method that adopted for analysis. The results indicated that in case of self-compacted reactive powder concrete rather than normal concrete gave deflection less and also there was a different result of deflection according the type of slab boundary condition supports.

Experimental and numerical study of influence of crude oil products on the behavior of reactive powder and normal strength concrete slabs

This paper examines the usefulness of using reactive powder concrete (RPC) as a better option for constructing crude oil tanks. The effect of 2 types of crude oil products (kerosene and gas oil) on the structural behavior of RPC and normal strength concrete (NSC) slab specimens is experimentally and numerically investigated after being immersed for 180 days. The experimental program consisted of three groups of slab specimens; reference group (cured normally and tested at the age of 180 days), immersed in kerosene product group, and immersed in gas oil product group. Each of the groups consisted of testing (3) RPC slabs with a thickness of (20, 40 and 60 mm), and (1) NSC slab with (60 mm) slab thickness. A numerical finite element (FE) analysis has been done for the reference and immersed RPC slabs using the damage-plasticity constitutive model that readily available in the software package ABAQUS. The test results showed that the effect of each type of crude oil products on the load-bearing capacity of RPC slabs was nearly negligible with the highest reduction of 2.58% from its ultimate load after immersion in gas oil product. On the other hand, NSC slabs lost about (10.15 and 12.57%) of the ultimate load after being soaked in kerosene and gas oil respectively.

Numerical analysis of ultra-high strength fibre-reinforced concrete slabs

Reactive Powder Concrete (RPC) is one the latest developments in concrete technology, also known as ultra-high-performance concrete (UHPC). It is characterised by the use of high cement content, with very high mechanical strength, high durability, in most cases, a quantity of steel fibres. A hollow core slab, also known as a void slab, hollow core plank, or simply a concrete slab is a precast concrete slab frequently used in the construction of floors in multi-story apartment buildings. The presence of holes in the reinforced concrete is necessary to act as ducts for services as well as having the structural purpose of reducing the weight of the slabs. This study examines previous experimental research results for 26 slabs in terms of examining the behaviours of reactive powder concrete slabs with longitudinal hollow cores of various sizes under various loading situations by changing the a/d ratio. The ANSYS computer program was used to investigate the behaviours of some of these slabs, and parametric studies were used to study the effects of the compressive strength of the concrete, types of support, and different steel reinforcement diameters. The results obtained using finite element solutions showed good agreement with experimental results.

Experimental Investigation of Impact Load Effect on the Flexural Behavior of Reactive Powder Concrete Slabs with Different Thicknesses

Recently, buildings have been exposed to terrorist attacks that generate impact loads on their elements and affect their serviceability loads, which is the thing that inspired researchers to investigate the properties of reactive powder concrete, such as strength, serviceability loads, impact load, and the influences of impact loads on standard weight concrete separately. Therefore, the main goal of this paper is studying the flexural behavior of reactive powder concrete after applying impact load caused by the attacks. For this study, three reactive powder concrete slabs: the first one is with 80-mm thickness, the second one is with 60-mm, and the third one is with 40-mm thickness, were statically loaded after being subjected to impact load. Moreover, then a number of the three slabsꞌ properties were investigated, such as flexural load capacity, deflection, and number and widths of cracks. The laboratory tests have approved that the slab with the higher thickness and steel fiber has improved and provided the best serviceability loads after being dynamically loaded.

Effect Of Reinforcement Ratio On Punching Shear Strength Of Reactive Powder Concrete Slab Reinforced With CFRP Bars

This work is devoted to study the effect of reinforcement ratio (ρ) on punching shear strength of reactive powder concrete slab reinforced with CFRP bars. The experimental program includes investigating the effect reinforcement ratio (ρ) on the first crack, type of failure, load – deflection curve and compression the ultimate punching shear capacity with ACI – 440 equation. All tested slabs were with dimension (1150 × 1150) mm and tested under concentrated load on column at the center of the slab.

Punching Shear Strength Of Reactive Powder Concrete Slab Reinforced With CFRP Bars

This work is devoted to study punching shear strength of reactive powder concrete slab reinforced with CFRP bars. The experimental program includes investigating the effect thickness of slab on the first crack, type of failure, load – deflection curve and compression the ultimate punching shear capacity with ACI – 440 equation. All tested slabs were with dimension (1150 × 1150) mm and tested under concentrated load on column at the center of the slab.

Behavior of High-Speed Railway Ballastless Track Slabs Using Reactive Powder Concrete Materials

AbstractThe precast ballastless track slab has been widely applied in the Chinese high-speed railway system. However, the current slabs, made of normal concrete (NC) materials and designed in a “plane” structural configuration, were found vulnerable to the train loads and temperature effects. This paper proposed an innovative slab type, which was made of an alternative reactive powder concrete (RPC) material and designed in a “frame” structural type. Four frame slabs with different cross section profiles were parametrically investigated, and the best configuration was proposed. The results demonstrated the proposed RPC slabs can well meet the requirements of the stiffness and strength. Compared with the NC plane slabs, the warping deformation of the RPC frame slabs were decreased as much as by 41.7% and 37.0%, respectively, under the −10°C temperature gradients and the combination of train and temperature effects. The simulated tensile stresses were within the corresponding RPC strength capacity. The crac...

Simulation of the Reactive Powder Concrete (RPC) Behavior Reinforcing with Resistant Fiber Subjected to Blast Load

In research or experimental works related to blast loads, the amount of explosion material and distance of explosion point are very important. So, in this paper has been attempted to present a parametric study of the reactive powder concrete subjected to blast load. The effect of the different amount of TNT adopted the literature, distance of explosion point from RPC slab and also the location of explosion charge (horizontal and vertical coordinates form the center of specimens) has been investigated. In order to the analytical simulation of RPC behavior against blast and also the accuracy of acquired results, at first using ABAQUS software, a RPC slab studied in the literature has been verified. The obtained results are showed that the simulated model of RPC is match with literature one. In the next stage, a case study of the effect of explosion charge and also the distance of explosion point from RPC and NSC (normal strength concrete) slabs have been examined, and the results have been compared. It’s noted that the NSC slab is supposed to be a reinforced concrete, whereas 2% volume of special short steel fibers were used in the RPC specimen. The acquired results have been showed that the RPC have better blast explosion resistance than reinforced normal strength concrete.

Effect of Steel Fiber on Punching Shear Strength of Non-Rectangular Reactive Powder Concrete Slabs

Effect of Steel Fiber on Punching Shear Strength of Non-Rectangular Reactive Powder Concrete Slabs

English

In this paper, the material performance of Reactive Powder Concrete (RPC) with two different curing conditions, water-curing of 25°C and heat-treatment of 90°C and 95% relative humidity was experimentally studied. An experimental investigation is carried out to study the influence of using steel fiber and heat-treatment on RPC slab specimens. All the slabs are simply supported along the four edges and loaded concentrically by a square plate of dimensions (70×70×25 mm). The test results showed adequate improvements by increasing adding steel fiber, using of heat-treatment on the compressive strength, indirect tensile strength and modulus of elasticity. It also showed a great positive effect on the flexural strength. The 28-day compressive strength varied between 163.4 and 194.6 MPa for the non-heat-treated and heat-treated specimens. Test results proved that the increase slab thickness leads to significant increase in ultimate load. The ultimate load of RPC slabs that have 20, 40 and 60 mm thickness are 17.5, 13.0 and 12.6% respectively compared to RPC slab specimens non-heat-treated when steel fibers are used at 2% by volume and the percentage increment when thickness decrement. It was found that the deflection at ultimate load, showed a significant decrease when the slab thickness was increased. Key words: Reactive powder concrete; mechanical properties; curing conditions; steel fibers

Ultimate Bearing Capacity of Steel-Reactive Powder Concrete Composite Beams

Concrete slab in the negative moment area of continuous steel-concrete composite beams is prone to crack due to the low tension strength of common concrete, which could result in the decreasing of the strength and durability. To solve this problem, a method of replacing the concrete slab with reactive powder concrete (RPC) slab which is of super high strength, durability, toughness and volume stabilization is presented. According to the constitutive relation and the high tension strength of RPC, the normal section failure mode is defined as the critical crack state, and the calculation formula of ultimate bearing capacity is deduced. Finally, some parameters that influence the ultimate bearing capacity are analyzed, such as the height ratio of RPC slab to whole beam, width ratio of RPC slab to steel beam, and the ratio of reinforcement of RPC slab. Compared with the steel-concrete composite beams, it is indicated that in the precondition of RPC slab unallowable crack in negative moment area, the ultimate bearing capacity of steel-RPC composite beams can still be increased, and the crack resistance, stiffness and durability can all be enhanced greatly.