Hydrogen gas storage place has been increasing daily because of its consumption. Hydrogen gas is a dream fuel of the future with many social, economic and environmental benefits to its credit. However, many hydrogen storage tanks exploded accidentally and significantly lost the economy, infrastructure, and living beings. In this study, a protection wall under a worst-case scenario explosion of a hydrogen gas tank was analyzed with commercial software LS-DYNA. TNT equivalent method was used to calculate the weight of TNT for Hydrogen. Reinforced concrete and composite protection wall under TNT explosion was analyzed with a different distance of TNT. The initial dimension of the reinforced concrete protection wall was taken from the Korea gas safety code book (KGS FP217) and studied the various condition. H-beam was used to make the composite protection wall. Arbitrary-Lagrangian-Eulerian (ALE) simulation from LS-DYNA and ConWep pressure had a good agreement. Used of the composite structure had a minimum displacement than a normal reinforced concrete protection wall. During the worst-case scenario explosion of a hydrogen gas 300 kg storage tank, the minimum distance between the hydrogen gas tank storage and protection wall should be 3.6 m.

Concrete pavement proportions are increasing in Korean expressways, resulting in increased maintenance cost. The length of degenerate concrete pavements that have exceeded the design life (20 years) was 1150 km in 2015 and 2605 km in 2020 and is expected to rapidly increase. To extend the service life of concrete pavements, life-cycle cost (LCC) analysis was conducted on asphalt and concrete overlays, based on the different maintenance methods. LCC analysis was performed when the shoulder was used and when it was not used between 6000 and 35,000 AADT traffic according to the two-lane and four-lane traffic. During overlay, one lane was completely blocked, and the value per vehicle was converted into the user cost using the Construction Analysis for Pavement Rehabilitation Strategies software, according to whether the shoulder was used to maintain the number of lanes. In addition, LCC analysis was conducted by examining the construction cost and life-cycle according to each overlay method. When the shoulder was used, the total construction cost decreased, owing to the reduction in user cost, indicating that the implementation of the traffic measure of using the road shoulder improves user satisfaction and cost. The asphalt overlay was observed to be more favorable than concrete overlay in terms of the initial total construction cost. However, under a 20-year cycle, the economic efficiency of concrete overlay was higher than that of asphalt overlay. After repairing the deteriorated target sections of concrete pavements, the overlay method (asphalt or concrete) ought to be selected according to the target service life for beneficial economic effect. Concrete overlay was to obtain about 20% or greater LCC effect compared to asphalt overlay, and at least 5% or more additional LCC effect obtained when the shoulder was used.

Many researchers have studied explosion prevention and fire resistance of high-strength concrete mixed with organic fiber and steel fibers. The fire resistance of high-performance fiber reinforced cement composites is desirable in terms of physical and mechanical properties. However, the use of a polymer as an alternative to organic fiber has not been clearly studied. In this study, a slurry infiltration method was used to obtain slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs) specimens. Powder polymer was used instead of organic fibers during mixing of the slurry. The compressive and flexural strengths of the specimens after 1 hr of high temperature exposure according to the KS F 2257 (ISO 834) standard fire-temperature curve were measured. The addition of the polymer before and after high temperature (about 945 °C) exposure affected the strength of the SIFRCCs. The compressive and flexural strengths were decreased after exposure to high temperature in comparison with SIFRCCs without polymer because polymer create capillary pores due to melting and burning when exposure to high temperature. This minimizes the vapor pressure inside the concrete model and reduces the failure of the concrete model. The experimental results showed that the flexural strength at a high temperature for 1.0 % polymer content was the highest at 53.8 MPa. The flexural strength was reduced by 40~50% when compared to the flexural strength before high temperature exposure and comparing to SIFRCCs without polymer, the compressive strength in 1.5% polymer is lower, owing to voids that are created in the SIFRCCs after exposure to a high temperature.

The development and importance of tunnels are increasing worldwide, and countries like Korea, where about 70% of the total land is covered with mountain regions, need more tunnel constructions to connect different routes of roads for safe and efficient transport. This study applied fire to the 200 mm × 200 mm × 200 mm concrete specimens, similar to the Rijkswaterstaat (RWS) fire, through an electric furnace. Thermocouples were placed inside the specimens to analyze the temperature during the occurrence of fire. Experimental and simulation thermal analysis during the occurrence of fire was analyzed. The experimental temperature at different depths agreed with the simulation results. Different international fire curves were applied to study the temperature inside the concrete through simulation by LS-DYNA. Concrete with different thicknesses of fireproof board was analyzed through simulation, and using fireproof board reduces the inside temperature during fire occurrence. Among the studied international fire curves, modified hydrocarbon fire curves had a high-temperature effect on concrete.