Building Management Hawaii June/July 2013 - (Page 26)

Asphalt Alternatives Concrete parking and driveways deliver. By Wayne Kawano ConCrete /aSphalt D riveways and parking areas are an integral part of total site building management. From the perspective of a building’s maintenance and financing, the cost benefit value of concrete for driveways and parking areas are becoming more evident to building owners. By choosing concrete pavements, building managers are selecting a more cost-effective, durable pavement that will require much less maintenance over its lifetime. A concrete parking area delivers beauty, durability, value and significant environmental benefits. It stands the test of time better than any other leading building material. Concrete service life is measured in decades but when the end finally comes, concrete can be crushed and recycled into a high quality aggregate for many applications. Environmental concerns and new technologies make concrete an even smarter choice today. Pervious concrete, a specialized concrete innovation, allows rainwater to pass through and thereby supports ground water recharge and tree growth—both of which are crucial to the Islands. Example of pervious concrete Pervious concrete may also reduce or eliminate the need for traditional storm water management systems. Additional benefits of lighter colored concrete is that it reduces the “heat island” effect as well as lowering lighting costs. Concrete can also be made using residual fly ash from our coal burning power plant (in Kapolei). Fly ash is a byproduct from burning pulverized coal in electric power generating plants. During combustion, mineral impurities in 26 June - July 2013 BMH Ultra-Thin Whitetopping (UTW) at H-1 Aiea/Honolulu Loop the coal fuse in suspension, cool and solidify into spherical glassy particles called fly ash. The fine powder resembles Portland cement but it is chemically different. Rehabilitating a deteriorated asphalt pavement? An alternative to consider is Ultra-Thin Whitetopping (UTW). UTW is a process in which a 4-inch-thick, high-strength, fiber-reinforced concrete is placed over an existing asphalt surface that has been milled, broomed and cleaned. The resulting composite pavement delivers the long life and performance characteristics of concrete pavement at a competitive cost. Work with a contractor who will help you: • Prepare the subgrade for best performance—compacted and uniform. Pavement thickness requirements and performance strength depends on load-bearing capacity and uniformity of the subgrade. • Choose the correct material and proportions. Quality concrete starts with consistent, high quality material per the American Society for Testing and Materials (ASTM) C94, a Standard Specification for Ready-Mixed Concrete. The standard addresses requirements for production and delivery of ready mixed concrete. Typically concrete specified at 28-day compressive strengths of 4,000 psi (pounds per square inch) is adequate for most areas. Compressive strength is the most common and easiest property of concrete to measure, as such, most often used when specifying concrete. • Select the optimum concrete thickness. For driveways and parking areas accommodating light trucks, typically a 5- to 6-inch-thick concrete pavement is required. The American Concrete Institute (ACI) 330 Guide for Design and Construction of Parking Lots has a design table for thickness design based on traffic category and subgrade values or soil condition. • Determine joint guidelines. Laying out joints in a slab requires good engineering judgment based on a four basic rules: – Joint spacing should not exceed 24 times the pavement thickness with a maximum spacing of 15 feet. – Lay out joints to form relatively square panels. – Joints should have a depth of at least one-fourth the slab thickness to create a weakened plane to form the control joint. – Concrete pavements should not interface with adjacent columns, walls or utility structures....Isolation joints extend the full depth. Wayne Kawano is president of the Cement and Concrete Products Industry of Hawaii (CCPI). CCPI is a nonprofit trade organization formed in 1965 dedicated to serving Hawaii’s concrete construction industry by providing technical resources, consultation and educational training/ certification for concrete products and techniques.

Table of Contents for the Digital Edition of Building Management Hawaii June/July 2013

Special Section: BIA Renaissance Awards
Solar & More - Made In The Shade
Solar Options For Condos
Beyond PV…The Power Of The Negawatts
Solar On The Highrise
On The Farm With PV
The Reality Of Exploring Solar
Steep-Slope Solar
Concrete & Asphalt - Fresh Surfaces for Work & Play
Pavement Maintenance 101
Asphalt Alternatives
Rocky Road
Pavement Preservation
Painting Top 5 Painting Tips
Painting & Exterior Finishes
Lead & Rules
On Site: Renting Delinquent Units

Building Management Hawaii June/July 2013