• International Journal of Highway Engineering
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• v.19 no.5
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• pp.33-42
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• 2017

PURPOSES : The purpose of this study is to suggest the construction and quality control method for the re-repair of a deteriorated partial depth repair for sections of Portland cement concrete pavement. METHODS : An experimental construction was conducted to extend the repair width for removing an existing repair section. A removal method was used to ensure early performance for a deteriorated partial depth repair section. Bond strength and split tensile strength were measured at the near vertical interface layer between the existing pavement and repair material. The area was analyzed for various conditions such as the extended repair area and the removing method of the existing repair section. RESULTS : As a result of analysis of bond strength and split tensile strength, the bonding performance of a milling removed section was improved over a cutting and hand breaker removed section. The bond strength was analyzed to increase slightly as the extended repair width for removing the existing repair section increased. The split tensile strength did not show a clear relationship to an increased extended repair width of an existing removed repair section. CONCLUSIONS : The milling removal method should be applied in the removal of existing deteriorated partial depth repair sections. The extended repair width for a re-repair section should be wider than the existing partial depth repair with at least a 75-mm length and width for the bond strength and the split tensile strength.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.1-8
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• 2013

PURPOSES : This study is to evaluate the feasibility of using the alkali activated cement concrete for application of partial-depth repair in pavement. METHODS : This study analyzes the compressive strength of alkali activated cement mortar based on the changes in the amount/type/composition of binder(portland cement, fly ash, slag) and activator(NaOH, $Na_2SiO_3$, $Na_2CO_3$, $Na_2SO_4$). The mixture design is divided in case I of adding one kind-activator and case II of adding two kind-activators. RESULTS : The results of case I show that $Na_2SO_4$ based mixture has superior the long-term strength when compared to other mixtures, and that $Na_2CO_3$ based mixture has superior the early strength when compared to other mixtures. But the mixtures of case I is difficult to apply in the material for early-opening-to-traffic, because the strength of all mixtures isn't meet the criterion of traffic-opening. The results of case II show that NaOH-$Na_2SiO_3$ based mixtures has superior the early/long-term strength when compared to NaOH-$Na_2SiO_3$ based mixtures. In particular, the NaOH-$Na_2SiO_3$ based some mixtures turned out to pass the reference strength(1-day) of 21MPa as required for traffic-opening. CONCLUSIONS : With these results, it could be concluded that NaOH-$Na_2SiO_3$ based mixtures can be used as the material of pavement repair.

• Clinics in Shoulder and Elbow
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• v.17 no.2
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• pp.91-100
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• 2014

Partial-thickness rotator cuff tear (PTRCT) is not single disease entity but one phase of disease spectrum. Symptoms of PTRCT vary from being asymptomatic to severe pain leading to deterioration in quality of life. Pathogenesis of degenerative PTRCT is multifactorial. Whereas articular sided PTRCT is usually caused by internal causes, both internal and external causes have important role in bursal sided PTRCT. A detailed history, clinical examination and magnetic resonance angiography are used in the diagnosis of PTRCT. Treatment of PTRCT is chosen based on age, demands of patients, causes and depth of tear. In most patients, non-operative treatment should be initiated. Whereas debridement can be done for less than 6 mm of articular sided PTRCT and in less than 3 mm of bursal sided PTRCT, repair techniques should be considered for higher grade PTRCT than that. Although the effect of acromioplasty is not clear, acromioplasty may be performed when the extrinsic causes appear to be the cause of tear. Either transtendon repair technique or repair after tear completion provided satisfactory clinical outcomes in treatment of articular sided PTRCT.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.353-358
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• 2001

The cement concrete pavements are designed twenty years of performance life in Korea. At the present time, some expressways have been elapsed seventy percent of performance life which are detecting local failures. The most repair methods using to repair failures are partial depth repair and full section repair. These methods are most important bonding strength between rapid curing materials and substrate concrete pavements. This study was performed to evaluate bonding strength of the composites section made of rapid curing material and substrate concrete pavements. The pull-out tester was used to test bonding strength for the composites section made of each materials. In the results of the test, the bonding strength values of the epoxy mortar and acrylic mortar are higher than those of the other materials. The performance life of repaired section is affected by various factor. The bonding strength of bonded composites section may be affect the performance life, significantly.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.569-575
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• 2007

The repair of concrete surfaces does not normally take into account structural tolerance for longer service lift and better capabilities of concrete structures. In particular, the repair of surface spelling completes as mortar is applied, which does not display additional structural performances. The use of crimped wire mesh for better construction and fracture resistance, however, expects to have some reinforcement effects. Particularly, it is also expected that the repair of bottom part in structures built between bridges like irrigation structures results in the increase of flexural resistance. Therefore, this study is intended to perform the repair using crimp wire mesh and examine strength depending on the repair section and depth. For this, a slab with 150 mm in depth, 3,000 mm in length and 600 mm in width and total 8 objects to experiment such as upper part, upper whole, bottom part, bottom whole and crimp wire mesh reinforced are manufactured to perform flexural performance. The results of the analysis show that yield strength and failure load increase as the depth of repair materials in the experiment reinforced with crimp wire mesh get bigger. In the same condition, repair of bottom part is able to increase internal force of bending force. Besides, the results show that partial repair of structures under bending force cannot produce flexural performance. Consequently, the repair method with crimp wire mesh results in the increase of flexural resistance.

• Journal of the Korean Arthroscopy Society
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• v.13 no.3
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• pp.242-248
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• 2009

Purpose: To evaluate the clinical and radiologic results of the arthroscopic rotator cuff repair for partial articular surface tendon avulsion lesion. Materials and Methods: Twelve patients with symptomatic, partial articular surface tendon avulsion underwent arthroscopic rotator cuff repair between Mar. 2006 and Sep. 2008. The mean follow-up period was 18.3 months(12~36 months), and the mean age at the time of surgery was 46.9-year-old(19~64 years). Three cases had underwent rotator cuff repair after conversion to full-thickness tear and nine cases had transtendon repair with preserving bursal side cuff. Results: The mean VAS during motion was 6.2 before treatment and 2.0 at final follow-up (p<0.001). The passive forward flexion improved from $163.3^{\circ}$ preoperatively to $169.8^{\circ}$ postoperatively (p=0.038). The mean UCLA score improved from 18.4 preoperatively to 30.1 with 2 excellent, 8 good and 2 fair results at final follow-up. The mean KSS improved from 61.8 preoperatively to 76.8 at final follow-up. By examining the postoperative MR images of 5 patients, complete healing was observed in all of them. Conclusion: Arthroscopic rotator cuff repair may be an effective procedure for partial articular surface tendon avulsion in pain relief and improvement of the range of motion. If the remaining bursal side cuff fibers are intact, transtendon repair procedure with preserving the intact bursal layer of the tendon can be considered. If the remaining bursal side cuff fibers are friable or little, completion from partial-thickness to full-thickness tears with subsequent cuff repair can be considered.

• Computers and Concrete
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• v.20 no.5
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• pp.573-582
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• 2017

Chloride-induced cover cracking will aggravate the performance deterioration for RC structures under the chlorideladen environment, which may endanger the safety of structures and occupants. Traditional design method cannot ensure that a definite performance is satisfied. To overcome the defects, a study on the performance-based design method was carried out in this paper. Firstly, the limit state functions were established for the corrosion initiation and cover cracking. Thereafter, the uncertainty analysis was performed to study the effects of random factors on the time-dependent performances. Partial factor formulae were deduced through the first-order reliability method for performance verification. Finally, an illustrative example was presented and the sensitivity of cover depth to other parameters was carried out. It is found that the uncertainties of the random variables have great effects on the required cover depth. It is demonstrated that the performance-based design method can ensure that the target performance can be satisfied and support to formulate a rational maintenance and repair strategy for RC structures under the chloride environment.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.23-32
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• 2009

In this paper an experimental program was launched to determine the mechanical and durability properties of spall repair materials (RCC: 3 items, PCC: 2 items, PC: 3 items). Test items were mechanical property tests such as setting times, strengths, modulus of elasticity, plastic shrinkage, and durability tests such as dynamic modulus ratio, bond property with freeze-thaw, water absorption, chemical resistance, ultraviolet exposure. Modulus of the PC products exhibits ductile while the modulus is in the order of RCC > PCC > PC. At early ages the PC products experience higher plastic shrinkage than others, henceforth stable at 28 days. Other test results such as dynamic modulus ratio, absorption, and chemical resistance show that the PCs are superior to the PCCs and the RCCs. Except for PC-2, all patch materials had bond strength more than 1.3MPa after freeze-thaw cycles of 200~300 while the PCs and the PCCs seem to be better than the RCCs. With 500 hours of ultraviolet exposure, all patch materials showed to have no crack or deterioration at the surface.

• Clinics in Shoulder and Elbow
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• v.2 no.2
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• pp.178-186
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• 1999

Twenty-three patients with chronic shoulder pain beyond 6 months after the fracture of the greater tuberosity underwent arthroscopic treatment and were retrospectively assessed after an average of 29 months(range, 22 to 40 months). There were 18 men and 5 women with the average age of 39 years(range, 24 to 61 years). Fourteen were isolated fractures and nine were related to acute anterior instability episode. The average displacement of the fracture was 2.3mm(range, 0 to 4mm) on the anteroposterior view of the plane radiographs. At the time of arthroscopy, all patients had partial thickness rotator cuff tears in the articular surface. The cuff tears were located on the tuberosity fracture area and were an Ellman's grade I to n in depth. With the arthroscopic debridement or repair of the tear depending on the condition of the tear itself, as well as the subacromial decompression, the UCLA score revealed good to excellent results in 20 and fair in 3 patients. Nineteen of the patients had returned to the previous level of activities. The patient with a higher activity demand revealed a lower level of activity return(p=0.034). The partial thickness rotator cuff tear should be considered in patients with chronic shoulder pain after the minimally displaced fracture of the greater tuberosity, and arthroscopic debridement or repair is an appropriate procedure.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.77-88
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• 2006

The maintenance / repair of concrete pavements has become an issue as a result of increasing of concrete pavements' service year. Asphalt overlay is applied to the concrete pavements after partial repairs on all occasions. This thesis discusses the application standard, evenness, skid resistance, noise, economical efficiency, extension of life span, etc. of diamond grinding, a method of maintenance about concrete pavements. Based on this, it was applied to the field and measured the performance. It was measured the longitudinal evenness of before and after the construction through measurement equipment. and surveyed the skid resistance the each lane classified using the SN standard value. In case of noise, it is selected the kind of vehicle, velocity, then measured the noise between control and constructed site. In addition, it is evaluated the average texture depth. As a result of the analysis, longitudinal evenness is improved about $6{\sim}40%$, skid resistance is improved 66% at first section,37% at second section. Noise is reduced 3.4dB average, and average texture depth is 79% deeper than control section. Therefore, it can be concluded that diamond grinding is suitable as maintenance / repair method of concrete pavements.