CONCRETE SLABS -JAPAN

THE THICKNESS DESIGN OF CONCRETE SLABS, IN ACCORDANCE WITH THE PROVISION OF ROAD CONSTRUCTION ORDNANCE, MAY BE 20 CM, 23 CM AND 25 CM DEPENDING ON THE TRAFFIC VOLUME, HOWEVER, 23 CM IS BEING ADOPTED MOSTLY AT PRESENT AND 20 CM THICKNESS IS USED VERY SELDOM. AN ANALYTIC METHOD IS PROPOSED BASED ON THE RESULTS OF EMPIRICAL STUDY ON THE METHOD BY WHEEL LOAD STRESS AND TEMPERATURE STRESS AND COMBINATIONS OF BOTH. THIS METHOD REVEALS THAT THE PORTION OF THE MOST SEVERE STRESS CONDITION IN CONCRETE SLABS DOES NOT EXIST IN THE CORNER, BUT IN THE LONGITUDINAL EDGE. THIS CONFORMS TO THE FACT THAT LATERAL CRACKS PREVAIL IN CONCRETE SLABS. THE CONCRETE PAVEMENT MANUAL STIPULATED THAT REINFORCING WIRE MESH SHALL BE EMPLOYED IN ORDER TO PREVENT THE DEVELOPMENT OF CRACKS, AND FURTHERMORE DOWEL BARS TO TRANSVERSE JOINT AND TIE BARS TO LONGITUDINAL JOINT SHALL BE USED, BECAUSE THESE STEEL BARS HAD PROVED TO BE VERY EFFECTIVE IN INCREASING THE STRUCTURAL STRENGTH OF CONCRETE SLABS. THE FLEXURAL STRENGTH OF 40 KG/CM SQUARED OR OVER HAS BEEN ADOPTED FOR A LONG TIME AS THE STANDARD FOR THE DESIGN STRENGTH OF CONCRETE. HOWEVER, BECAUSE OF THE INCREASING TRAFFIC VOLUME REQUIREMENTS THIS VALUE WAS INCREASED TO 45 KG/CM SQUARED. THE COEFFICIENT 1.15 IS USED TO MULTIPLY THE DESIGN STRENGTH TO DETERMINE THE REQUIRED AVERAGE STRENGTH OF MIXED DESIGN OR THE PROPORTIONAL STRENGTH. FOR DETERMINING THE CONSISTENCY OF CONCRETE FOR USE IN PAVEMENT, A METHOD OF VIBRATORY CONSISTENCY TEST HAS BEEN DEVELOPED. FOR CONCRETE MATERIALS, IT IS COMMON PRACTICE TO USE PORTLAND CEMENT, RIVER SAND AND RIVER GRAVEL AND A WATER REDUCING AGENT AS AN ADMIXTURE. SINCE PROCUREMENT OF GRAVEL IS BECOMING DIFFICULT, THERE IS A TENDENCY TO EMPLOY CRUSHED STONE AS A SUBSTITUTE. IT IS PROPOSED TO PUT PRE-MORTAR MIXED CONCRETE TO PRACTICAL USE IN ORDER TO PRODUCE HIGH EARLY STRENGTH CONCRETE, AND THIS IS BEING CARRIED OUT EXPERIMENTALLY ON THE WORK SITE. SPECIAL CONCRETE PAVEMENTS SUCH AS PRE- STRESSED CONCRETE PAVEMENT, CONTINUOUSLY REINFORCED CONCRETE PAVEMENT, ETC. ARE AT PRESENT AT THE STAGE OF IN-SITU TEST FOR PRACTICAL USE.

• Supplemental Notes:
  • No Iv-8, pp 3-29, 11 FIG, 13 TAB
• Authors:
  • Ito, S
• Publication Date: 1967

Media Info

• Serial:
  • Perm Intl Assoc Road Congresses Proc
  • Publisher: Xiiith Congress, Tokyo

Subject/Index Terms

• TRT Terms: Admixtures; Alluvium; Concrete; Concrete pavements; Concrete tests; Consistency; Continuously reinforced concrete pavements; Design standards; Gravel; High early strength cement; Material reinforcement; Pavement cracking; Portland cement; Prestressed concrete; Sand; Slabs; Strength of materials; Stresses; Temperature; Thickness; Traffic volume; Vibration devices; Wheel loads
• Uncontrolled Terms: Lateral loads
• Old TRIS Terms: Concrete consistency; River deposits; Thickness design; Vibrators
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 00205545
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 3 1994 12:00AM