High-efficiency Carbonation Modification Methods of Recycled Coarse Aggregates

To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.

Effect of High Temperature Curing on the Frost Resistance of Recycled Aggregate Concrete and the Physical Properties of Second-Generation Recycled Coarse Aggregate under Freeze-Thaw Cycles

With the emphasis on environmental issues,the recycling of waste concrete,even recycled concrete,has become a hot spot in the field of architecture.But the repeated recycling of waste concrete used in harsh environments is still a complex problem.This paper discusses the durability and recyclability of recycled aggregate concrete(RAC)as a prefabricated material in the harsh environment,the effect of high-temperature curing(60℃,80℃,and 100℃)on the frost resistance of RAC and physical properties of the second generation recycled coarse aggregate(RCA_(2))of RAC after 300 freeze-thaw cycles were studied.The frost resistance of RAC was characterized by compressive strength,relative dynamic elastic modulus,and mass loss.As the physical properties of RCA_(2),the apparent density,water absorption,and crushing value were measured.And the SEM images of RAC after 300 freeze-thaw cycles were shown.The results indicated that the frost resistance of RAC cured at 80℃ for 7 days was comparable to that cured in the standard condition(cured for 28 days at 20℃±2℃ and 95%humidity),and the RAC cured at 100℃ was slightly worse.However,the frost resistance of RAC cured at 60℃ deteriorated seriously.The RAC cured at 80℃ for 7 days is the best.Whether after the freeze-thaw cycle or not,the RCA that curd at 60℃,80℃,and 100℃ for 7 days can also meet the requirements of Grade III RCA and be used as the aggregate of non-bearing part of prefabricated concrete components.RCA_(2) which is cured at 80℃ for 7 days had the best physical properties.

Optimization of Coarse Aggregate Content based on Efficacy Coefficient Method

The influence of coarse aggregate content on concrete properties was investigated.From the perspective of Frame Concrete Theory,six groups concrete were produced with the same proportion except for coarse aggregate content,with coarse aggregate content of 0%,40%,50%,60%,75%,and 80%,respectively.Slump,compressive and flexural tensile strengths,elastic modulus,and water penetration were tested to research the effect of coarse aggregate content on concrete.The experimental results reveal that slump reduces with increasing of coarse aggregate content,while compressive strength,elastic modulus and flexural tensile strength increase with the coarse aggregate content increasing,and water penetration reduces with coarse aggregate content increasing before 75% then increased.Workability,strength,durability and economical indexes system were established to optimize the coarse aggregate content in concrete based on efficacy coefficient method.The optimization results show that when coarse aggregate content is 60%,the system efficacy coefficient reaches to 0.89,and it expresses the better comprehensive performance.

Shear behavior of coarse aggregates for dam construction under varied stress paths

Coarse aggregates are the major infrastructure materials of concrete-faced rock-fill dams and are consolidated to bear upper and lateral loads. With the increase of dam height, high confining pressure and complex stress states complicate the shear behavfor of coarse aggregates, and thus impede the high dam＇s proper construction, operation and maintenance. An experimental program was conducted to study the shear behavior of dam coarse aggregates using a large-scale triaxial shear apparatus. Through triaxial shear tests, the strain-stress behaviors of aggregates were observed under constant confining pressures： 300 kPa, 600 kPa 900 kPa and 1200 kPa. Shear strengths and aggregate breakage characteristics associated with high pressure shear processes are discussed. Stress path tests were conducted to observe and analyze coarse aggregate response under complex stress states. In triaxial shear tests, it was found that peak deviator stresses increase along with confining pressures, whereas the peak principal stress ratios decrease as confining pressures increase With increasing confining pressures, the dilation decreases and the contraction eventually prevails. Initial strength parameters （Poisson＇s ratio and tangent modulus） show a nonlinear relationship with confining pressures when the pressures are relatively low. Shear strength parameters decrease with increasing confining pressures. The failure envelope lines are convex curves, with clear curvature under low confining pressures. Under moderate confining pressures, dilation is offset by particle breakage. Under high confining pressures, dilation disappears.

Performance Degradation of the Repeated Recycled Aggregate Concrete with 70% Replacement of Three-generation Recycled Coarse Aggregate

The feasibility of using different generations recycled coarse aggregate（RCA） on structural concrete was fully evaluated by studying the performance of the recycled coarse aggregates and their corresponding concretes, the different generations of RCA were recycled by following the repeated mode of ‘concrete-waste concrete-coarse aggregate-concrete＇. Moreover, the focus was on ‘three generations＇ of repeated RCAs, the RCA was produced by crushing and regenerating the artificial accelerated degraded concrete, the process was designed to follow the nature degradation of the concrete with a coupling action of accelerated carbonation and bending load. The properties of x-generation（x=1, 2 or 3） of repeated RCA were systematically investigated and the compressive and splitting tensile strengths of relating structural concretes（with 70% replacement of x-generation of RCA） were studied accordingly. The results show a competent compressive and splitting tensile strength of 30 MPa at 28 th day of structural concretes with all generations of repeated RAC. And the gradual degraded performance of the repeated RCAs was observed with an increased numbers of repetition（1〉2〉3 generations）, the overall performances of all repeated RCAs fulfill the Class Ⅲ according to Chinese Standards GB25177-2010. Our gained insight demonstrates a feasibility of using at least 3 generations of repeated RCA for the production of normal structural concrete.

Effect of CO_(2) Curing on the Physical Properties of Recycled Coarse Aggregate with Different Attached Mortar Contents

The effects of carbon dioxide (CO_(2)) curing conditions (temperature,relative humidity and CO_(2) curing time) on the physical properties of recycled coarse aggregate (RCA) with varying attached mortar (AM) contents were studied.Before and after CO_(2) curing,the physical properties in terms of the apparent density,water absorption and crushing value of RCA were tested and the quality of RCA was determined.Besides,scanning electron microscope was used to observe the microstructure of RCA.Results show that the physical properties variation of RCA with higher AM content are more significant,and the quality of RCA with lower AM content is easier to be upgraded during CO_(2) curing.The physical properties of RCA with 40.8% AM content are earlier stable than that with no less than 44.5% AM content during CO_(2) curing.The optimal temperature and relative humidity are 50 ℃ and 55% for CO_(2) curing,respectively.CO_(2) curing is incapable of upgrading the quality of RCA with AM no less than 50.6%.The quality of RCA with 44.5% AM content can be upgraded only under the optimum CO_(2) curing conditions.Under relative humidity higher than 40% and the CO_(2) curing time more than 12 h,CO_(2) curing upgrades the quality of RCA with 40.8% AM content.

Finite Element Analysis on the Uniaxial Compressive Behavior of Concrete with Large-Size Recycled Coarse Aggregate

To model the concrete with complex internal structure of concrete with large sized aggregates the effect of internal structure on uniaxial compression behavior are studied.Large-sized recycled aggregates behave differently in the concrete matrix.To understand the influence on concrete matrix,a finite element model was developed to model recycled aggregate concrete composed of multiple randomly distributed irregular aggregates and cement mortar.The model was used to calculate the effect of large-size recycled coarse aggregate(LRCA)on the strength of recycled aggregate concrete and simulate the compressive strength of cubes and prisms.The factors such as the strength of new concrete,the strength of old concrete,the defective element content,the shape of LRCA,the incorporation ratio of LRCA and the size of LRCA that can affect the strength of concrete are analyzed in this paper.Results showed that the influence of various factors on concrete strength are in the following desend-ing order:(i)strength of newly poured concrete;(ii)original strength of recycled aggregates;and(iii)defects.It can be seen that the cracking of the phase material elements starts along the bonding zones between gravel and mortar or the new and old mortar,then spreads to mortar and finally to LRCA.The cracking tendency is most significant in LRCA,which means that the fracturing is related to the fracture of the LRCA.After evaluating the variations in strength and quality of the recycled concrete,the influences on concrete strength and quality were studied.The results showed that the proposed concrete model with LRCA was successfully applied to studying the uniaxial compressive behavior of concrete with large-size recycled coarse aggregate.

Different Curing Systems on Mechanical Properties of Ultra-High Performance Concrete with Coarse Aggregate

High durability and high tensile strength makes ultra-high performance concrete( UHPC) an ideal material for bridges,while its early shrinkage in the construction of cast-in-situ mass concrete leads structure crack-easily,which restricts the application of UHPC in deck system. Whether reasonable amount of coarse aggregate can influence the strength of UHPC and improve the shrinkage performance or reduce the cost is still in doubt. Besides,in order to improve its constructability and workability, whether autoclaved curing system of UHPC can be changed remains to be further researched. In response to these circumstances, a systematic experimental study on the strength of UHPC mixed with coarse aggregate in different ratios has been presented in this paper. The three curing systems,namely standard curing,180-200 ℃/1. 1 MPa autoclaved curing,and hot water curing were tested to reveal the relationship between UHPC's properties and curing systems,and the UHPC ' s microstructure was also preliminarily studied by scanning electron microscope( SEM). The experimental research can draw the following conclusions. Under the condition of the same mix ratio, autoclaved curing guarantees the highest compressive strength,followed by hot water curing and standard curing. The compressive strength of concrete increases with the temperature in the range of 25 to 90 ℃ hot water curing,and high temperature in precuring period can speed up the strength development of UHPC,but the sequence of precuring period does not obviously affect the results. In 90 ℃ hot water and autoclaved curing,the strength is over 150 MPa,and it has little relation with gravel ratio. While the value increases first and then decreases in a lower temperature curing with the increasing of gravel amount,even only about 80 MPa at room temperature. The strength increases moderately along with the increase of the curing age by standard curing,especially in the initial stage.

Numerical Comparative Study on the Effective Replacement Thickness of Traditional Stone Coarse Aggregate or Steel-Slag Aggregate Mixtures in Improved Soft Fine Soils

This study uses Steel Slag Coarse Aggregate (SSCA) as a mixture replacement, preamble material to improve soft soils, which is economic, and has good effect environment. Recently, the development and utilization of by-product, waste and recycle materials must be studied and investigated as a source of improved material for soft soils as, an economic and good effect environmental. The study analyzes effects of both replaced mixtures, (SSCA) or (TSCA) on improved soil bearing capacity and expected settlement after verifying the model. Numerical modeling of the one of real store loaded strip using, PLAXIS, 2D, strain deformation behavior to achieve field visible and measured deformations of untreated soft soil. Numerical studies were devolved to investigate geomechanics parameters improved to compare between using (SSCA) or (TSCA) as, replacement mixture. Results demonstrate that using (SSCA) improved compressibility and strength of shallow soft soil layer significantly than using (TCSA) mixture, while (SSCA) improved strip footing ultimate bearing capacity, (UBC), by 84.4% compared with increase of 20.5% when using (TCSA) mixture at the same thickness. In addition, the study highlights the effective (SSCA) replacement thickness ranges between (0.65 ~ 0.80) footing width.

Effect of Partial Replacement of Coarse Aggregate with Electronic Waste Plastic in Light Weight Concrete

This study assessed the usefulness of the replacement of coarse aggregate partially with electronic waste(e-waste)plastic in lightweight concrete since developing countries have been challenged with management of e-waste as well as high cost of coarse aggregates for concrete production.Coarse aggregates were replaced with e-waste plastic in concrete at 5%,10%,15%,and 20% for a concrete class of C20.The particle size distribution of the e-waste plastic aggregates was determined as well as the slump,compressive strength,water absorption and bulk density of the concrete.Generally,the slump decreased as the e-waste increased.The compressive strengths decreased for the 5%and 10%replacement of coarse aggregates with e-waste but increased for the 15% and 20% replacement of coarse aggregate with e-waste.0% water absorption was obtained for the 15% and 20% e-waste content while the 10%e-waste concrete obtained 0.01% and the 5% e-waste obtaining of 0.013% after 28days of curing.The densities of 5%,10%,15% and 20% e-waste plastic content decreased as compared to the 0% e-waste plastic content.The values of compressive strength obtained showed that coarse aggregate replacements by e-waste plastic at 15% and 20% may be appropriate for lightweight concrete of class C20/25 since compressive strengths ranged between 16.09 Nmm^(-2) and 22.87 Nmm^(-2).This implies that partial replacement of coarse aggregate with e-waste plastic may be useful for lightweight concrete as well as helping in eradicating the environment of the menace of e-waste plastic.

Assessment of Geotechnical Properties of Laki Limestone for Coarse Aggregate, Nooriabad, Jamshoro Sindh, Pakistan

Present study is aimed at assessment of geotechnical properties of Laki limestone as coarse aggregate which is being quarried in Nooriabad area,Sindh,Pakistan.Coarse aggregate samples(n=20)of limestone were collected for the evaluation of physico-mechanical properties of the aggregate.Petrographic analysis revealed that the aggregate comprises of hard,compact,massive,crystalline and fossiliferous limestone.It is devoid of any reactive silica(chert,chalcedony)and other harmful constituents like clays or organic matter.Average values of specific gravity,absorption,bulk density,void content and combined index(EI+FI)of collected samples are 2.5,2.1%,1.54 g/cc,38.55%and 13.04%respectively.The values of specific gravity(2.3-2.9),absorption(0-8%),bulk density(1.28 g/cc-1.92 g/cc)and void content(30%-45%)are varying within the range of normal weight aggregate as per American concrete institute(ACI)specifications.On the other hand,absorption values of aggregate samples are slightly higher(2.1%)than the reference range(2%)but meet other requirements.Mechanical properties including aggregate impact value(8.58%),aggregate crushing value(26.66%),Loss Angeles abrasion value(24.77%),sodium sulfate soundness(4.72%),water soluble sulfate(0.006%)and water soluble chloride(0.005%)are found to be within corresponding guidelines set by ASTM.On the other hand,average carbonate content is found to be 89.64%indicating that Laki limestone is of slightly low purity.Except absorption,all physical and mechanical properties lie within specified ranges.It is concluded that Laki limestone is suitable for use as road aggregate and concrete mix design.

Chloride diffusion in concrete with carbonated recycled coarse aggregates under biaxial compression

Chloride attack on concrete structures is affected by the complex stress state inside concrete,and the effect of recycled aggregates renders this process more complex.Enhancing the chloride resistance of recycled concrete in a complex environment via carbonization facilitates the popularization and application of recycled concrete and alleviates the greenhouse effect.In this study,the chloride ion diffusion and deformation properties of recycled concrete after carbonization are investigated using a chloride salt load-coupling device.The results obtained demonstrate that the chloride ion diffusivity of recycled concrete first decreases and then increases as the compressive load increases,which is consistent with the behavior of concrete,in that it first undergoes compressive deformation,followed by crack propagation.Carbonation enhances the performance of the recycled aggregates and reduces their porosity,thereby reducing the chloride diffusion coefficient of the recycled concrete under different compressive load combinations.The variation in the chloride ion diffusivity of the carbonized recycled aggregate concrete with the load is consistent with a theoretical formula.

Effect of Lateritic Stone Aggregate and Coconut Husk Fiber on the Properties of Concrete

Natural stone aggregate forms the bulk volume of concrete and has contributed to the increased cost of concrete production. This has led to the search for alternate aggregates such as lateritic stone for concrete production. This paper investigates the engineering properties of concrete produced with lateritic aggregate (LA) as the coarse aggregate replacement and coconut husk fibre (CHF) as reinforcement. Natural stone aggregate was replaced by LA at 0%, 10%, 20%, 30%, 40%, and 50%, with 0.25% constant CHF by weight. A mix proportion of 1:1.5:3 with a water-cement ratio of 0.6 was used for producing concrete. A total of 162 specimens (90 cubes and 72 beams) were prepared and tested at the 7, 14, 21, and 28 days of curing. The highest compressive strength was 43.36 N/mm2 (10% LA replacement) as compared to the control of 41.51 N/mm2. The 10% LA replacement obtained the highest flexural strength of 5.35 N/mm2 as compared with the 5.29 N/mm2 for the control. The water absorption of the concrete increased from 2.8% (control) to 3.57% (50% replacement LA). Scanning electron microscopy (SEM) revealed micro gaps between CHF and LA concrete. The study, therefore, concludes that the use of LA and CHF positively influenced the strength properties of concrete. 10% LA replacement of coarse aggregate and 0.25% CHF is recommended to practitioners for use.

Quantification of coarse aggregate shape in concrete

The objective of this study is to choose indices for the characterization of aggregate form and angularity for large scale application. For this purpose, several parameters for aggregate form and angularity featured in previous research are presented. Then, based on these established parameters, 200 coarse quartzite aggregates are analyzed herein by using image processing technology. This paper also analyzes the statistical distributions of parameters for aggregate form and angularity as well as the correlation between form and angularity parameters. It was determined that the parameters for form or angularity of coarse aggregates could be fitted by either normal distribution or log-normal distribution at a 95% confidence level, Some of the form parameters were influenced by changes in angularity characteristics, while aspect ratio and angularity using outline slope, area ratio and radius angularity index, and aspect ratio and angularity index were independent of each other, respectively; and consequently, the independent parameters could be used to quantify the aggregate form and angularity for the purpose to study the influence of aggregate shape on the mechanical behavior of concrete. Furthermore, results from this study＇s in-depth investigations showed that the aspect ratio and the angularity index can further understanding of the effects of coarse aggregates form and angularity on concrete mechanical properties, respectively. Finally, coarse aggregates with the same content, type and surfaces texture, but different aspect ratios and angularity indices were used to study the influence of coarse aggregate form and angularity on the behavior of concrete. It was revealed that the splitting tensile strength of concrete increased with increases in the aspect ratio or angularity index of coarse aggregates.

Bond-Slip Behavior of Steel Bar and Recycled Steel Fibre-Reinforced Concrete

Recycled steel fiber reinforced concrete is an innovative construction material that offers exceptional mechanical properties and durability.It is considered a sustainable material due to its low carbon footprint and environmental friendly characteristics.This study examines the key influencing factors that affect the behavior of this material,such as the steel fiber volume ratio,recycled aggregate replacement rate,concrete strength grade,anchorage length,and stirrup constraint.The study investigates the bond failure morphology,bond-slip,and bond strength constitutive relationship of steel fiber recycled concrete.The results show that the addition of steel fibers at 0.5%,1.0%,and 1.5%volume ratios can improve the ultimate bond strength of pull-out specimens by 9.05%,6.94%,and 5.52%,respectively.The replacement rate of recycled aggregate has minimal effect on the typical bond strength of pull-out specimens.However,the ultimate bond strengths of pull-out specimens with concrete strength grades C45 and C60 have improved compared to those with C30 grade.The specimens with longer anchorage lengths exhibit lower ultimate bond strength,with a reduction of 33.19%and 46.37%for anchorage lengths of 5D and 7D,respectively,compared to those without stirrups.Stirrup restraint of 1φ8 and 2φ8 improves the ultimate bond strength by 5.29%and 6.90%,respectively.Steel fibers have a significant effect on the behavior of concrete after it cracks,especially during the stable expansion stage,crack instability expansion stage,and failure stage.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete under High Temperatur

This research aims to study the effect of elevated temperature on the compressive strength evolution of concrete made with recycled aggregate.Demolished building concrete samples were collected from four different sites in Saudi Arabia,namely from Tabuk,Madina,Yanbu,and Riyadh.These concretes were crushed and recycled into aggregates to be used to make new concrete samples.These samples were tested for axial compressive strength at ages 3,7,14,and 28 days at ambient temperature.Samples of the same concrete mixes were subjected to the elevated temperature of 300°C and tested for compressive strength again.The experimental result reveals that the recycled aggregate concrete samples have good quality at ambient and elevated temperatures and are considered fairly close to the concrete made with natural aggregate.However,recycled aggregate concrete at high temperatures showed higher strength degradation than natural aggregate concrete,but with differences that do not exceed 5%to 10%.The concrete samples made from recycled coarse aggregates also reached the design strength.It can be considered acceptable,considering the high variation in the concrete’s thermal response found in the literature.

Influence of the Granular Class of Crushed Granites on the Litho-Stabilization of Samo Laterites (South-East of Côte d’Ivoire)

Most of the laterites found in Ivory Coast do not meet the technical conditions to be used in their natural state for the design of road foundations. Also, to meet the growing needs for road materials, various amendments are made to them, including litho-stabilization. Thus, this study proposes to understand the influence of the granular class of natural aggregates on the performance of laterites. To achieve this objective, different proportions of crushed granites of class 0/5, 0/15 and 5/15 have been incorporated into the soils of southern Côte d’Ivoire, especially in Samo. This modified soil has been subjected to mechanical tests such as the modified Proctor and CBR test. The results obtained show that the dry densities of the incorporated laterites containing crushed granites increase with the content of natural aggregates and decrease with the increase in the water content. Likewise, the CBR bearing indices at 95% of the Modified Optimum Proctor of the different compositions (laterites + crushed granites) increase with the proportion of aggregates. The addition of coarse aggregates to the laterites therefore promotes the establishment of a framework which improves its bearing capacity. From 20% to 30% crushed granites respectively of class 0/15;0/5 and 5/15, the values of the CBR obtained are greater than those of 30% therefore these modified soils can be used as a foundation layer for traffic of T1, T2 and T3 type. Likewise, the laterites’ mixtures with at least 40% crushed granites of class 0/15 and 0/5 can also be used for the foundation and base layers.

Establishment of a three-dimensional particle library for graded crushed stone based on a new aggregate morphology characterization method

The morphology of graded crushed stone(GCS)particles has an essential influence on the performance of aggregate mixtures.The impact of particle shape is a comprehensive effect that cannot be considered separately,leading to difficulties in establishing the relationship between the mixture properties and the aggregate morphology by using laboratory methods.The discrete element method(DEM)is an effective way widely adopted to reconstruct the morphology of particles and simulate performance tests of granular materials.However,selecting limited particles characterizing a real particle-assembly for simulation is still a challenge in current research due to the inherent rich variability of particle shapes.In this study,based on the acquisition of three-dimensional(3D)aggregate shapes by using laser scanning,ellipsoid index(EDI)translating the particle shape as a function of surface area,volume,and contour length is proposed to comprehensively evaluate aggregate morphology.Further,a particle library capable of characterizing aggregate morphology distribution is established based on the statistics of the corresponding morphological characteristics of particle samples.The model reliability is validated by carrying out a series of experimental and numerical penetration tests with nine different gradations.The established particle library can be used to model aggregate mixtures and the proposed simulation framework is promising for optimizing the mixture gradation design numerically.

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate concrete

Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete(SSRAC)are analyzed by a series of axial compression tests.Two different types of fine(coarse)aggregates are considered:sea sand and river sand(natural and recycled coarse aggregates).Variations in SSRAC properties at different ages are investigated.A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of concrete.Supportive results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion content.The elastic modulus of SSRAC increases with age.However,the Poisson’s ratio reduces after 2 years.Typical axial stress-strain curves of SSRAC vary with age.Generally,the effect of coarse aggregates on the axial deformation of SSRAC is clear;however,the deformation differences between coarse aggregate and cement mortar reduce by adopting sea sand.The aggregate type changes the crack characteristics and propagation of SSRAC.Finally,an analytical expression is suggested to construct the long-term stress-strain curve of SSRAC.

The Permeability and Strength of Green High Performance Concrete

The permeability,alkali silica reaction,workability and strength of GHPC(green high performance concrete) were studied in this paper.The results show that GHPC has an excellent durability and the effects of mass ratio of flyash to high calcium slag,water binder ratio,content of water reducer,and crushed coarse aggregate type on the workability and strength of GHPC were considerably evident.A new path for the concretes continuous development was put forward.