ACI 224 . 3 R-95 Joints in Concrete Construction Reported by ACI Committee 224
nance of joints in concrete structures subjected to a wide variety of use and environmental conditions. In some cases, the option of eliminating joints is considered. Aspects of various joint sealant materials and jointing techniques are discussed. The reader is referred to ACI 504R for a more comprehensive treatment of sealant materials, and to ACI 224R for a broad discussion of the causes and control of cracking in concrete construction. Chapters in the report focus on various types of structures and structural elements with unique characteristics: buildings, bridges, slabs-on-grade, tunnel linings, canal linings, precast concrete pipe, liquid-retaining structures, walls, and mass concrete.
RIGID PAVEMENT ANALYSIS AND DESIGN
This study was conducted to characterize and compare currently available rigid pavement analysis models and design methods and to develop new rigid pavement designs to be evaluated in full scale experimental projects in an actual highway environment. The analysis models considered include: ILLI-SLAB, JSLAB, WESLIQID, WESLAYER, JCS-1, H51, CRCP-2, and RISC. The design methods include: 1985 AASHTO Guide, Zero Maintenance JCP-1, California DOT, PCA, RPS-3 Texas SDHPT, ARBP-CRSI and Illinois DOT. The capabilities, limitations, and assumptions of each of these models and methods are discussed in detail to assess their adequacy to assist in the design and analysis of rigid pavements. Based upon the results obtained, several models and methods are recommended for use in the development of new rigid pavement designs. A set of rigid pavement designs, featuring trapezoidal cross sections, widened truck lanes, permeable drainage layer, longitudinal drainage pipe, precoated dowels, shorter joint spacing (for JRCP) and tied PCC shoulders was developed for field testing through experimental projects in the various climatic zones of the United States. A project description form (PDF) is provided for the interested State agencies. Guidelines were developed for joint load transfer design and joint spacing. Predictive models for doweled and nondoweled joints were developed (A).
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.