PURPOSES : Concrete pavement is excellent in structural performance and durability. However, its functionality – such as noise and skid resistance – is a shortcoming. Functionality such as noise reduction and skid resistance of concrete pavement is affected by the texture surface, and the texture surface is classified according to the length of the wavelength. In recent years, Fine-size exposed aggregate concrete pavement has been applied, which has excellent structural performance and durability, and secures functionalities such as noise reduction and long-term skid resistance by randomly forming texture surface. Fine-size exposed aggregate concrete pavements are constructed by removing the surface cement binder to randomly expose coarse aggregate and their functionality is mainly governed by the surface texture. However, deteriorated concrete by tire-pavement friction and deicing agent may cause abrasion and aggregate loss on the surface texture; thus reducing their functional performances. Abrasion is created by the thin cutoff of aggregate texture under repeated tire-pavement friction. In addition, aggregate loss is defined by the detachment of aggregates from cement binder. This study aims to evaluate the abrasion and aggregate loss of Fine-size exposed aggregate concrete pavement surface texture under tire-pavement friction and scaling tests.
METHODS : In the study, abrasion and aggregate loss of tining and exposed aggregate concrete surface treatments were evaluated. Deterioration of each surface treatment was replicated by scaling test under ASTM C 672 test method. Afterward, abrasion test was conducted by ASTM C779 to simulate the tire-pavement friction under traffic. Consequently, abrasion and aggregate loss were measured.
RESULTS : Abrasion depth of non-scaling tining, 10-mm EACP, and 8-mm EACP was 1.76, 1.12, and 1.01mm, respectively. Compared to scaling surface treatments, the difference of abrasion depth in tining texture was the largest with value of 0.4mm. For both textures of finesize exposed aggregate concrete, abrasion depth difference was about 0.1mm. Moreover, The 10-mm EACP exhibited a 2.6% of aggregate loss rate caused by tire-pavement friction before conducting concrete deterioration test. After 40-cycle scaling test, aggregate loss increased up to 12.2%. For 8-mm EACP, aggregate loss rate was 1.7% on non-scaling concrete. Further, this rate was magnified up to 7.3% for the 40-cycle scaling concrete.
CONCLUSIONS : Under non-scaling or scaling tests, fine-size exposed aggregate concrete pavement showed better abrasion resistance than tining texture since tining was formed by aggregates and cement binder. Additionally, rate of aggregate loss was significant when EACP experienced the deicing agent under numerous cycles of freeze-thaw action.
PURPOSES: In this study, the effects of adding a superabsorbent polymer (SAP) to the concrete mixture on the strength of the concrete and abrasion resistance were analyzed, and whether the property of concrete can be improved by the internal curing effect of SAP was evaluated. METHODS: In this study, a total of eight different mixes were tested. The amounts of SAP added were 0%, 0.6%, 1.2% while that of silica fume were 0% and 6% based on the weight of the binder. The compressive test, rapid chloride penetration resistance test, and abrasion test were performed to verify the internal curing effects of SAP.
RESULTS : The compressive test showed that SAP concrete had greater compressive strength than ordinary concrete. Comparison of the compressive strengths of dry and wet cured specimens of each mixture showed that SAP concrete had a smaller difference compared with ordinary concrete. The rapid chloride resistance test showed that SAP did not increase chloride penetration resistance. However, since this experiment only considered wet curing, further investigation of dry curing is necessary. The abrasion resistance test showed that for the case of concrete cured under dry conditions without spraying the curing compound, the abrasion resistance of the SAP concrete improved by approximately 49% at 14 days and 27% at 28 days of curing compared with ordinary concrete.
CONCLUSIONS : The effect of SAP on the strength and abrasion resistance of concrete was analyzed. The results showed that the internal curing effect of SAP improved concrete strength and abrasion resistance. The internal curing effect maintains the overall internal humidity in concrete by supplying water held by the SAP to the dried cement paste.
PURPOSES : The purpose of this study is to analyze not only the strength but also the durability and abrasion resistance of concrete pavements as increasing the cases of domestic concrete pavement damage which do not meet the service years.
METHODS: The bottom layer of a two-lift concrete pavement was paved with original Portland cement (OPC) with 20~23 cm thickness. On the other hand, the top-layer, which is directly exposed to the environment and vehicles, was paved with high-performance concrete (HPC) with 7~10 cm thickness. For the optimal mixed design of the top-layer material of a two-lift concrete pavement, silica fume and polymer powder were mixed. Furthermore, it analyzes abrasion resistance of concrete as follow‘ ASTM C 779’which is dressing wheel abrasion test method.
RESULTS : As a result, abrasion resistance is improved with increasing the silica fume ratio. When the polymer powder is mixed, abrasion resistance of concrete is much improved. However, the effect of mixing ratio is not significant. It is very effective that adding both silica fume and polymer powder occur 20~40% of abrasion comparing with OPC variables.
CONCLUSIONS : The concrete strength and durability increased with silica fume and polymer powder. In particular, it is significant increasing strength of polymer powder under the flexural strength. In the abrasion resistance side, it is also significant when the silica fume and polymer powder used together.
In this thesis, it was considered that in durability characteristics of concrete pavements evaluation of strength characteristics as well as abrasion resistance is important as the domestic concrete pavements couldn't fulfill the public needs and cases of damage are increasing. In order to solve such problems, it is intended to compare the abrasion resistance in accordance with the mixing rate of admixtures (silica fume and polymer powder) which are incorporated in the upper layer of two-lift concrete pavement and find the optimum mixing rate for abrasion resistance by focusing on the high performance of concrete pavements through two-lift concrete pavements which use cellular sprayed concrete construction method. Both test results, which were performed based on ASTM C 779 B (dressing wheel abrasion test method) and ASTM C 944 (rotary cutter method) standards in accordance with silica fume and polymer powder mixing rate that was incorporated in the upper layer of two-lift concrete pavement, proofed that the abrasion resistance increased as the mixing rate of silica fume and polymer powder increased. However, it was also confirmed that if the mixing rate of admixtures is excessively increased it will not have an effect and it will rather decrease the abrasion resistance.
PURPOSES: In this study the influence factors related to abrasion resistance of interlocking concrete block have been evaluated, and comparisons between various domestic and foreign abrasion test methods was also accomplished. METHODS: The modified rotational cutting method suggested in ASTM C 944 was applied. Surface materials with different types of fine aggregate such as crushed sand, sea sand, and mixture of crushed and sea sand were tested to compare the aggregate effect for abrasion resistance. RESULTS: The different surface mixtures with various W/C ratios, mortar and fly ash ratios have been investigated for functional and economical considerations. CONCLUSIONS: This study had obtained reliable results by changing diamond blade of rotating cutter. Therefore, in order to improve the abrasion resistance of interlocking concrete block for road, a new mix design was proposed.
콘크리트는 일반적으로 구조물에 활용되는 재료로써 다양한 환경조건에 노출된다. 특히 물과 같은 매체를 통해 콘크리트에 유해한 인자가 유입되므로 많은 피해를 야기 시킨다. 이에 콘크리트 내구성을 높이기 위해 많은 재료가 개발되고 있는 실정이다. 그중에 실란과 실록산 화합물은 흡수방지제로 활용도가 높은 재료로 알려져 있다. 그러나 노후화되거나 열화된 콘크리트에 처리할 경우 기재 자체가 약해 쉽게 박리되어 그 기능을 상실하는 문제점이 있다. 그래서 본 연구에서는 실록산 화합물로 표면 처리된 멜라민-포름알데히드 수지를 활용해 콘크리트에 흡수방지제 효과와 동시에 표면강화 성능을 부여하기 위한 실험을 진행하였고, 이를 확인하기 위해 콘크리트의 기공률 및 표면경도 특성을 연구하였다.