Organizational, direct support and general support maintenance repair parts and special tools lists : drier-mixer, bituminous-concrete materials, wheel mounted, gasoline engine driven, 2 wheel, pneumatic tires, 3 to 10 ton per hr. (NSN 3895-00-755-4761) : Wylie model PM-415-MIL.

Includes index.

Direct support and general support maintenance repair parts and special tools lists : mixer, concrete, trailer mounted, gasoline driven; 16 cu. ft. w/water cooled engine NSN 3895-00-807-7985 ... w/air cooled engine NSN 3895-00-985-5335 ....

Includes index.

Organizational maintenance repair parts and special tools lists : mixer, concrete, trailer mounted, gasoline driven ; 16 cu. ft. w/water cooled engine, NSN 3895-00-807-7985, Construction machinery model 16SM, serial numbers 148883 thru 148982 & serial numbers 153351 thru 153609, w/air cooled engine, NSN 3895-00-985-5335, Construction machinery model 16SM, serial ...

Includes index.

Organizational maintenance repair parts and special tools lists : drier-mixer, bituminous-concrete material, wheel mounted, GED, 2-wheel, pneumatic tires, 3 to 10 ton per hour NSN 3895-00-832-6230, K.E. McConnaughay MDL HTD-A-67.

Includes indexes.

Direct support and general support maintenance repair parts and special tools lists : drier-mixer, bituminous-concrete material, wheel mounted, GED, 2-wheel, pneumatic tires, 30 to 10 ton per hour NSN 3895-00-832-6230.

Includes indexes.

Direct support and general support maintenance repair parts and special tools lists : non-tilt mixer, concrete NSN 3895-00-444-1531, T.L. Smith Company model 499A.

Includes index.

Organizational maintenance repair parts and special tools lists : non-tilt mixer, concrete, NSN 3895-00-444-1531, T.L. Smith Company model 499A.

Includes index.

Unit, direct support and general support maintenance repair parts and special tools list for saw, concrete, self propelled, abrasive disk, model C-3000-30, NSN 3895-01-303-8909.

"October 1991."

Unit, direct support, and general support maintenance repair parts and special tools lists : drier-mixer, bituminous, concrete material, wheel mounted, GED, 2-wheel, pneumatic tires, 3 to 10 tons per hour (NSN 3895-00-832-6230).

"June 1992."

Organizational maintenance repair parts and special tools lists : concrete - mobile mixer, body M919, model 8CM - 24/F, NSN 3895-01-028-4391.

Includes index.

Technology of repair for corroded reinforced concrete

A number of factors relating to various methods of repair for chloride initiated corrosion damage of reinforced concrete have been studied. A novel methodology has been developed to facilitate the measurement of macro and micro-cell corrosion rates for steel electrodes embedded in mortar prisms containing a chloride gradient. The galvanic bar specimen comprised electrically isolatable segmental mild steel electrodes and was constructed such that macro-cell corrosion currents were determinable for a number of electrode combinations. From this, the conditions giving rise to an incipient anode were established. The influence of several reinforcement and substrate primer systems upon macro-cell corrosion, arising from an incipient anode, within a patch repair have been investigated. Measurements of electrochemical noise were made in order to investigate the suitability of the technique as an on-site means of assessing corrosion activity within chloride contaminated reinforced concrete. For this purpose the standard deviation of potential noise was compared to macro-cell galvanic current data and micro-cell corrosion intensity determined by linear polarisation. Hydroxyl ion pore solution analyses were carried out on mortar taken from cathodically protected specimens. These specimens, containing sodium chloride, were cathodically protected over a range of polarisation potentials. Measurement of the hydroxyl ion concentrations were made in order to examine the possibility of alkali-silica reactions initiated by cathodic protection of reinfored concrete. A range of mortars containing a variety of generic type additives were examined in order to establish their resistances to chloride ion diffusion. The effect of surfactant addition rate was investigated within a cement paste containing various dosages of naphthalene sulphonate.

Aspects of the prevention and repair of chloride-induced corrosion of steel in concrete

Sodium formate, potassium acetate and a mixture of calcium and magnesium acetate (CMA) have all been identified as effective de-icing agents. In this project an attempt has been made to elucidate potentially deleterious effects of these substances on the durability of reinforced concrete. Aspects involving the corrosion behaviour of embedded steel along with the chemical and physical degradation of the cementitious matrix were studied. Ionic diffusion characteristics of deicer/pore solution systems in hardened cement paste were also studied since rates of ingress of deleterious agents into cement paste are commonly diffusion-controlled. It was found that all the compounds tested were generally non-corrosive to embedded steel, however, in a small number of cases potassium acetate did cause corrosion. Potassium acetate was also found to cause cracking in concrete and cement paste samples. CMA appeared to degrade hydrated cement paste although this was apparently less of a problem when commercial grade CMA was used in place of the reagent grade chemical. This was thought to be due to the insoluble material present in the commercial formulation forming a physical barrier between the concrete and the de-icing solution. With the test regimes used sodium formate was not seen to have any deleterious effect on the integrity of reinforced concrete. As a means of restoring the corrosion protective character of chloride-contaminated concrete the process of electrochemical chloride removal has been previously developed. Potential side-effects of this method and the effect of external electrolyte composition on chloride removal efficiency were investigated. It was seen that the composition of the external electrolyte has a significant effect on the amount of chloride removed. It was also found that, due to alterations to the composition of the C3A hydration reaction products, it was possible to remove bound chloride as well as that in the pore solution. The use of an external electrolyte containing lithium ions was also tried as a means of preventing cathodically-induced alkali-silica reaction in concretes containing potentially reactive aggregates. The results obtained were inconclusive and further practical development of this approach is needed.

Robustness of corroded reinforced concrete structures

Short Term Scienti c Mission, COST ACTION TU-0601

Precast concrete wall-foundation connection. Development of a seismic dissipative connection

Seismic events are a major factor to consider in structural design of buildings in many countries. With the purpose of saving lives, most of the design codes lead to structural solutions that withstand large seismic actions without collapsing, but without taking into account a possible usage of the structures after the earthquake. As a result, it is necessary to consider the time needed to repair/retrofit the damaged structures (i.e. the downtime) since this period of inactivity may result in huge financial implications for the occupants of the buildings. In order to minimise the damages and simplify repair operations, structural solutions with rocking systems and negligible residual displacements have been developed during the last two decades. Systems with precast concrete rocking walls were studied with the aim of investigat- ing suitable and convenient structural alternatives to minimise the damage in case of an earthquake. Experimental, numerical and analytical analyses on post-tensioned solutions, with and without energy dissipation devices, were carried out in this research. The energy dissipation devices were made from steel angles that were further developed during the research. Different solutions for these devices were experimentally tested under cyclic loading and the results are presented. Numerical and analytical work on steel angles was also carried out. Regarding the concrete rocking wall systems, two concrete rocking wall systems were studied: post-tensioned walls and post-tensioned walls with energy dissipation devices. In the latter, the solution was to fix them externally to the wall, allowing their easy replacement after an earthquake. It is shown that the dissipaters are a viable solution for use in precast concrete rocking wall systems. A building case study is presented. The comparison between a traditional monolithic system and a hybrid solution was carried out, allowing the evaluation of the efficiency of the solution that was developed.

Tensile properties of polymer repair materials - effect of test parameters

In this research, five types of polymer repair materials were selected for investigation of the influence of sample shape, deformation rate and test temperature on the mechanical properties determined with an uniaxial tensile test. The results showed the clear effect of measurement conditions on tensile strength, elongation and modulus of elasticity. The highest tensile strength and modulus of elasticity were exhibited by epoxy resin for the filling of concrete cracks, which achieved 1% elongation. The lowest coefficient of dispersion characterized the results of tensile test carried out using dumbbell samples at a deformation rate of 50 mm/min. The effect of temperature varied with the material type.