When dealing with the issue of repair of concrete pavement repair using dowel bar retrofit technique, it is very desirable for the repair material to have high fluidity that can ensure good compaction and facilitate flow to tight spaces, preferably without the use of a vibrator. The focus of this project was on identifying critical properties that control long-term performance of repair concrete, especially rapid-setting materials extended using pea gravel (maximum size aggregate 9.5 mm). In the first phase of this project, four commercial rapid-setting materials (CRSMs) were selected and development of mixture proportions in terms of optimum pea gravel content and water content was performed. Optimized mixtures were further evaluated at three different initial temperature conditions. The properties evaluated included workability, setting time, rate of compressive strength developed, slant shear bond strength, freeze-thaw resistance, air-void system characteristics of hardened concrete, drying shrinkage and cracking potential. It was observed that some of the CRSMs evaluated did not meet requirements of ASTM C 928. All, except one, CRSMs tested exhibited low resistance to freezing and thawing but all had high resistance to cracking. In the second phase of the project, rapid-setting self-consolidating concrete (RSSCC) was developed using ternary blend of cementitious materials, high-range water reducer (HRWR) and accelerators. Slump flow, visual stability index (VSI), compressive strength at various ages and the power consumption values for the mortar mixer indicated that a five minutes mixing sequence involving a 2-step addition of HRWR produces stable RSSCC mixture. The results of various tests carried out indicate that it is possible to develop a small aggregate size-based self-consolidating repair concrete that achieves a compressive strength of 19 MPa at the end of 6 hrs, has good bond characteristics and has excellent freezing and thawing durability (DF>90%).

The subjects of the symposia are on composite materials with matrices behaving as brittle in normal or special conditions. Brittle matrix composites are applied in various domains (civil engineering, mechanical equipment and machinery, vehicles, etc.) and in the last decades their importance is increasing together with their variety. Papers include: aggregate-binder composites (concretes, fibre concretes, rocks); sintered materials (ceramics); high strength composites with brittle matrices. In principle, the general problems of structures made of composite materials are not included in the papers. Various approaches to the material engineering problems are presented in the papers.

Effective load transfer across Portland cement concrete pavement joints significantly decreases pavement deterioration. Areas of concern with using dowel bars include high costs, due to the labor-intensive procedure of retrofitting, and corrosion associated with standard mild steel epoxy-coated dowels. This research addresses these problems by evaluating four dowel bar details tested in an accelerated manner. Retrofit testing was performed using mild-steel epoxy coated dowels and fiber reinforced polymer (FRP) dowels. The details tested provide comparisons among dowel bar materials, depth of placement, number of dowels used, and dowel diameter. Verification testing of previously tested details is also presented.