A series of 16 reinforced concrete beams was tested to evaluate the flexural performance of RC beams strengthened by epoxy bonded plates after repair. The key parameters for this study were the repair materials, polymer, cementitious materials and strengthening materials, steel plates and carbon fiber sheets. The repaired specimens failed by a typical flexural mode with minor interfacial bond failure. The results show that the flexural performance of the strengthened beams is varied depending on the repaired material. Specimens with epoxy polyester resins and latex modified cementitious mortars are effective for repairing the concrete beams, compared to specimens repaired with cement mortar. The flexural capacity of specimen strengthened by epoxy bonded steel plates or carbon fiber sheets after repair are less than those of strengthened specimens without repair. The interfacial behavior between was the repair material and strengthening material observed as the major influencing factor for the composite structures.

The expanded use of fiber reinforced polymer (FRP) tendons as prestressing and post-tensioning tendons requires that these tendons be subjected to high axial loads while bent or harped around a curved surface. This paper describes the behavior of one type of CFRP tendon when subjected to combined axial loading and harping. Four test series to study the tendon fiber strain distribution and seven test series to study the tendon ultimate strength were conducted. The tendons were subjected to various combinations of axial loading and harping around a curved surface. Test parameters for the ultimate strength tests included tendon axial load, bend angle, and curvature of harping point. Harping points were set to either 1 in. (25 mm), 5 in. (127 mm), or 20 in. (508 mm) radius. Ultimate strength tests included static strength tests and fatigue tests. Results of the static tests indicate that at failure, the flexural strains at harped point far exceed the average fiber strain recorded in uni-axial tensile strength tests. The flexural strain is defined as the difference between strain readings from a 0.125 inch (3.2 mm) strain gage placed on the tendon bend outside face and the tendon average axial strain. No flexural strains were observed away from the tendon bend beyond about 6 in. (152 mm). Based on the tests, an expression for the tendon flexural strain at harped point as a function of axial load, bend angle, and harping plate curvature was developed. This expression for flexural strain at harped point was used in a maximum strain failure criteria model that accurately predicts the failure of specimens tested in this research. The results of the fatigue testing indicated no degradation of tensile strength due to fatigue loading.

In this study, the properties of self-flowing concrete, of which flow was more than 60 cm, containing fly ash were experimentally investigated and compared with those of ordinary concrete. Flow test, slump test and setting time test on five types of self-flowing and three types of ordinary concrete mixtures were carried out to obtain the properties for flowability and workability of fresh concrete. The mechanical properties of hardened concrete were also investigated in terms of compressive strength, splitting tensile strength, modulus of elasticity, creep and drying shrinkage. In fresh concrete, it was found that self-flowing concrete had excellent workability and flowability compared with ordinary concrete. Self-flowing concrete also had good mechanical properties at both early and late ages with compressive strength reaching as high as 40 MPa at 28 days. The creep of self-flowing concrete investigated was greater than that of ordinary concrete at early ages, and drying shrinkage was much higher.

An experimental study was designed to accomplish the following: 1) Compare strengths of cylinders prepared by vibration or rodding following current ASTM C 3 1 and C 192 requirements for the number of layers; 2) investigate whether the experience of the operator affects cylinder strength when vibration and rodding are used to consolidate the specimens; and 3) compare the strengths of 100 x 200-mm rodded cylinders prepared by using two or three layers. Two experiments were designed: 1) a half-fraction, factorial design with the following factors: cement content, slump, cylinder size, consolidation method, and operator; and 2) a comparative design to compare the strengths of 100-mm diameter cylinders rodded using two or three layers with the strengths of 150-mm diameter cylinders. The following summarizes the observations from the first experiment: Overall, the 100-mm cylinders (three layers) were 1.5% stronger than the 150-mm cylinders. However, due to a significant interaction effect of size*cement content; there was a 3.4% difference at the high cement content and no statistically significant difference at the low cement content. Overall, the rodded cylinders were 4.2% stronger than the vibrated cylinders. There was a significant interaction effect of method*size; therefore, the rodded 100-mm cylinders were 7.4% stronger than the vibrated 100-mm cylinders, but there was no difference between the 1 50-mm cylinders prepared by the two methods. Also, the rodded 100-m cylinders were 4.6% stronger than the rodded 150-mm cylinders, but the vibrated 150-mm cylinders were 1.6% stronger than the vibrated 100-mm cylinders. The experience of the operator had no effect. There was no significant interaction between slump and method. There was no significant interaction between cement content and method. In the second experiment it was found that the strength differences between 100-mm and 150-mm rodded cylinders were reduced by one-half when two layers, instead of three were, were used to cast the 100-mm cylinders.

This paper provides details on five projects where high-performance concrete was used for construction of concrete floors and pavements. Four of these projects are located in Australia and one in Malaysia. Emphasis is placed on strict quality assurance in accordance with AS/NZS 9002 Quality Systems for Production and Installation. Assessment of the concrete quality was made in accordance with the inspection and test plan proposed by the concrete manufacturer and the project specification. The main assessment criteria for each of the following projects were performance based. Chullora printing facility used 80-MPa and lOO-MPa concrete to achieve a very high abrasion resistance, very flat floor to accommodate the continuous turning actions of computer guided vehicles transporting full rolls of newsprint. lOO-MPa textured road pavement was constructed at Wilton Road, Maldon to facilitate frequent turning of heavy vehicles on a public road adjacent to the cement works. National Rail Corporation freight terminal crane roadway was constructed at Chullora using lOO-MPa concrete with a 10-MPa flexural strength. The roadway was subjected to road loadings 24 hours after concrete placing. A distribution centre at Bukit Raja in Malaysia, for which a 40-MPa concrete was specified for the construction of a very flat floor with a high abrasion resistance. An 80-MPa concrete was specified for the construction of a trial pavement for the network of roads within the North Parkes underground gold mine in western New South Wales. The performance criteria was consistently achieved on each project, due to a very well co-ordinated team effort. Because normal concrete is not suitable for this type of construction, high-performance concrete must be specially designed in conjunction with specific methods of floor or pavement construction to yield significantly reduced overall maintenance and life cycle cost savings.