Recently there are many study on the effect of improving the compressive strength of MWCNT-cement composites. However study related to MWCNT-cement yet insignificant to the domestic. The MWCNT have excellent mechanical characteristics which are mixing cement. MWCNT-cement composites can be expected improving compressive strength. This parametric experimental study have verified to increasing compressive strength of mortar composites mixing MWCNT as W/C, curing age.
Traditional demolition methods for maritime bedrock may not adequate specially for urban areas and historical places due to hazard of explosive and noise. Therefore, an use of soundless chemical demolition agent (SCDA) increased to reduce the noise and avoid from explosive methods. However, there is no guideline or design code for using SCDA. In this study, crack control for maritime bedrock demolition using SCDA is performed.
In the paper, accelerated corrosion test for RC (Reinforced Concrete) samples with normal steel and FRP Hybrid Bar are performed and their flexural capacity is evaluated. Furthermore UV(Ultrasonic Velocity) measurement is attempted for analysis of variation of UV due to corrosion conditions. For commercial production of FRP Hybrid Bar, bond strength evaluation through long-term submerged corrosion test is required.
In the paper, newly invented FRP Hybrid Bar and normal steel are embedded in RC beam member, and ICM(Impressed Current Method) is adopted for corrosion acceleration. Corrosion amount level of 4.9∼7.8% are measured in normal RC member and the related reduction of flexural capacity is measured to –25.4∼-50.8%. But, durability evaluation through long-term submerged condition is required for actual utilization.
This study was evaluated fluidity properties on the performance of fiber dispersion of basalt fiber in mortar matrix as part of a basic study for development to fiber reinforcement mortar using basalt fiber. Results of assessment, fiber dispersion performance of of fiber reinforcement mortar using basalt fiber, showed that viscosity agent is more effective to improve the fluidity and fiber dispersion than superplasticizer.
The ultimate load of beam reinforced with polymer cement slurry(PCS)-coated rebar that is developed to replace the epoxy coated rebar having many defects is almost the same as that using plain rebar, and is higher than that of epoxy-coated rebar. In special, that using EVA 100% with ultra high early strength cement is a little bigger than that using plain rebar. In this study, it is also apparent that PCS-coated rebar can replace epoxy-coated rebar to solve the corrosion problem in marine construction field.
In experimental results, the prediction equation for 28 day-strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 day-strength. In order to acquire the reliability, all mixture were repeated as 3 times and each mixture order was carried out by random sampling. The prediction equation for 28 day-strength of GGBF slag concrete by 1-day strength won the good reliability.
Concrete represents the mostly widespread structural material for construction of buildings due to its mechanical properties such as durability, variability and availability of resources. But, cement production is associated with large energy consumption and consequently with high CO2 emissions. This paper analyzed the amount of CO2 emissions in various concrete mix design on the viewpoint of service life periods using Korean LCI DB.
This study is the study of the strength characteristics of the study of the natural durability enhancement materials that can reduce cracking of the concrete. The durability enhancement materials of natural were substituted 10%, 20%, 30% of cement, the results were confirmed excellent strength as the more increasing the natural durability enhancement.
As the results of study, the difference of marshall stability is insignificant according to steel mesh reinforcement. But property of flexural toughness index of steel mesh reinforced asphalt concrete is improved 2.2 times compared to the Plain.
In this study, longitudinal strain distribution of rebar in the 1-directional tension test are evaluated with an image processing method (IPM). From these results, it is estimated that the necking region can make the over estimation of elongation of rebar, therefore, the estimation except the necking region can be suggested to evaluate the true elongation of rebar.
In this study, longitudinal strain distribution of spliced rebar in the 1-directional tension test are evaluated with an image processing method (IPM). From these results, it is estimated that the coupler can decrease the elongation at the ultimate load, therefore, the spliced rebar with coupler should be evaluated to be used in the RC structure with LSD.
In this study, sulfuric acid resistance of sulfur polymer surface protected concrete was evaluated. From the test result, the case of the surface protected test specimen showed no degradation of the concrete surface. Therefore, it is considered as applying on waste water disposal plants, drainage pipelines, etc is possible.
This study analyzed the temperature rise and thermal cracking in the nuclear containment structures owing to the hydration heat of cementitious materials. The main parameters investigated were the one-layer casting height of concrete to examine the shortening of construction time of the structures. The current mixture proportions of concrete needs to be modified to increase the one-layer height of concrete, minimizing the likelihood of the occurrence of thermal cracks.
Recent developments in technology, the use of complex composite section, such as composite truss girder is increasing. These sections, the tensile stress will be generated internal and external constraints caused by other materials. Thus, the effects of the panel point on the concrete slab was studied through the structural analysis.
Purpose of this study is investigates mechanical property of Chemically Bonded Phosphate Ceramic(CBPC). For the purpose of the investigation of mechanical property, compressive stress and length change ratio were evaluated. Evaluated results of compressive stress was shown that compressive stress increased depending on aging time. On the other hand, length change ratio decrease depending on aging time.
In this study, fluidity and compressive strength characteristics of latex modified mortar was compared with each latex types. From the test result, fluidity of the product "A-a" was most outstanding and the product "B-b" revealed the highest compressive strength. Following this experiment range, when using the produce "B-b" it is considered to be able to secure proper fluidity and strength.
In this study, deterioration degrees of concrete was investigated at a lab under cycling freeze-thaw, which is major durability performance deterioration factors of concrete. After 300 cycles of freeze-thaw, relative dynamic modulus of elasticity and compressive strength of concrete mixed with normal Portland, SF, and Ny over 90 to 93% showed relatively low resistance of approximately 78 to 87% of those values of FA-PP-02. The SF-01 specimen showed the most excellent freeze-thaw resistance among the tested high performance concrete.
This study was intended to estimate the effect of adding stone dust into cement mortar on the rheological properties. it was found that higher the content of stone dust decrease the yield stress but there was no noticeable correlation between stone dust dosage and the plastic viscosity.
Differential scanning calorimetry of the aggregated impregnated with PCM indicates 4~10 J/g of the amount of heat storage capacity. The results show that it is considered that lightweight aggregate concrete impregnated with PCM may have thermal energy storage capacity.