Concrete Materials Laboratory

Concrete, Japan

Concrete Materials Laboratory

Concrete, Japan

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Ito M.,Vibration Isolating Materials Laboratory | Sakamoto T.,Vibration Isolating Materials Laboratory | Uehara M.,Concrete Materials Laboratory | Tsuruta K.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Flame resistance is an important requirement for products used in railway vehicles. Heretofore, a halogen-based fire retardant has been mainly applied; however, halogen acid is known to generate a gas which is poisonous to human beings in a combustive state. Accordingly, there is growing interest in halogen-free fire retardants. In recent years, the flame resistance of polymeric products has been increased remarkably through application of nanocomposites technology because nanocomposites, even in small quantities of additives improve their properties, of which flame resistance. For this reason studies have been carried out the application of nanocomposites to the floor sheet of railway vehicle.


Ueda H.,Concrete Materials Laboratory | Tamai Y.,Concrete Materials Laboratory | Kudo T.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Cement-based repair materials are generally used as concrete repair patches. However, these repair materials can generate cracks and shelling, and decreasing concrete structure durability. In this study, we carried out, among others, adhesive strength and water permeability tests to improve the durability of concrete structures repaired by the aforementioned materials, to clarify the properties of the interface between the concrete and the repair materials. Results showed that water permeability played an important role in the interface between the concrete and the repair materials. This evaluation makes it possible to improve the durability of repaired concrete structures.


Uehara M.,Concrete Materials Laboratory | Mizuno K.,Concrete Materials Laboratory | Sato T.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2012

The alkali-silica-reaction (ASR) suppression effect of Li-containing zeolite prepared from metakaolin was found to be greater than that of commercial Ca-A type zeolite. Material containing more Li-ABW type zeolite suppressed ASR more effectively when used as an admixture. In contrast, material containing more Li-EDI type zeolite was more effective in suppressing ASR when employed as grout for cracks. Trial samples were made of a new crack grout with Li-EDI type zeolite, which is more effective in suppressing ASR than a commercial crack grout with Ca-A type zeolite. No problems were detected with the physical characteristics of this material when used as grout.


Ueda H.,Concrete Materials Laboratory | Suzuki H.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2016

As water is related to many deterioration mechanisms affecting concrete structures, knowledge of water movement behavior in concrete is very useful for the effective maintenance of these structures. In this study, based on many data obtained from monitoring sensors embedded in concrete samples, it was clarified that properties of water penetration into concrete surfaces differ according to component materials, mixing proportions and curing methods of the concrete. It was also made clear that water penetration behavior into the interface between the concrete and the section repair materials depends on pretreatment methods applied before addition of the restoration materials.


Sato T.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

Two types of short sleeper were manufactured, both using fiber-reinforced geopolymers instead of ordinary Portland cement. One type of short sleeper was produced with reduced use of steel rods which provide tensile reinforcement, and the other without any steel rods. Plug pull-out tests and flexural tests on the two types of short sleeper showed that model, containing 1.5 vol% steel fibers without any steel rods, met the performance requirements of short sleepers. And the other type of sleepers, containing 1.5 vol% polyvinyl alcohol (PVA) fibers, 2.0 vol% polypropylene (PP) fibers, and 1.0 vol% aramid (AR) fibers with reduced use of steel rods, met the performance requirements of short sleepers.

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