The housing problem in Nigeria is both quantitative and qualitative. The qualitative aspect, which has to do with the maintenance of the existing stock, has assumed greater significance because of the need to preserve the existing stock and bring it to acceptable standards of living. Tenants in institutional housing are major stakeholders who directly bear the brunt of the disrepair of the houses. Hence they have a role to play to optimise the maintenance of their houses within the very limited resources available to the maintenance departments. The study was carried out to evaluate the maintenance awareness and responsibilities of tenants and quantitatively analyse their satisfaction with the state of maintenance of their houses. The results showed that the tenants had a high level of maintenance awareness and responsibility but their satisfaction with the maintenance of their houses was just average.

A study of tenants’ maintenance awareness, responsibility and satisfaction in institutional housing in nigeria

A real time differential asphalt pavement quality sensor of the present invention is adapted to measure asphalt density in real time using a differential approach. Two sensors, one in the front of a roller and another behind the roller, measure reflected signals from the asphalt. The difference between the reflected signals provides an indication of the optimal compaction and density of the asphalt pavement. The invention looks at the change in variance over successive passes to determine when the optimal level of compaction has been reached.

Real time asphalt pavement quality sensor using a differential approach

Accurate pavement performance estimation is very important for the managing and maintaining of surface transportation infrastructure. In the present study, a new model for the prediction of present and future performance of flexible pavements is developed using the fuzzy logic approach. The database of the model is able to use numerical measurements and also linguistic statements. Many models developed in the literature neglect the parameters that have little bearing on performance. However, it is a well known fact that these parameters do have an effect on performance to some degree. Different parameters were considered in the model as accepted by the authorities, and as having little bearing on performance. For each parameter, a certain weight was appointed, and the parameters that affected performance were assigned greater weights while the others were assigned smaller weights. As a result, the current model in the fuzzy logic approach is more flexible than the current Pavement Serviceability I...

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Performance model for asphalt concrete pavement based on the fuzzy logic approach

This paper presents a pavement maintenance management system (PMMS) composed of the following modules: (1) Pavement‐network identification; (2) pavement condition survey and rating procedures; (3) distress‐prediction models; (4) maintenance activities and strategies; and (5) economic analysis and prioritized maintenance programs. Modules 1 and 2 follow the PAVER procedures. The distress‐prediction models are developed from local network data for load associated distress and climate/durability related distress. These models predict the extent of distress—not condition indexes. Nineteen different maintenance activities are defined in module 4. Each distress is assigned the most appropriate maintenance activity in order to bring any given pavement section up to target condition for each year. In module 5, the PMMS incorporates a unit‐cost analysis of all maintenance activities and a cost‐benefit scheme that permits the determination of the most economic order of maintenance activities in terms of work quanti...

Practical applications of models for pavement maintenance management

Presented in this paper is a methodology for nondestructive pavement testing and its application in the rehabilitation program of the Talara and Piura Airports, located in the Pacific region of Peru approximately 1000 to 1100 km north of Lima. The area's water table is 2 to 8 m under the subgrade surface and the annual rainfall is less than 150 mm. Each airport has a 2500-m runway and is used mainly by medium-sized and small jet aircraft such as B-727s, B-737s, and F-28s. The existing pavement materials do not meet standard specifications for plasticity, gradation, and California bearing ratio, and the thickness is less than that recommended by the Federal Aviation Administration. Nevertheless, 15 years' experience generally indicates adequate pavement performance. It was concluded that the most practical way to interpret the actual performance of these marginal materials is to use nondestructive testing to determine the elastic parameters of the existing subgrade and pavement. The methodology used in Piura and Talara is based on the Hogg model of a thin plate on an elastic foundation. The subgrade modulus can be determined without prior knowledge of the thickness or the characteristics of the pavement layers. The pavement modulus can then be calculated for any given load and center deflection. The survey indicates that existing pavement materials in such arid zones can generate sufficient bearing capacity to support traffic loads of B-727s, B-737s, F-28s, and DC-8s. The test results were used to upgrade the existing airport so that they could carry 600 annual operations of B-727s with total gross weights of 160,000 lb for 20 years.

Using nondestructive testing in the semi-arid zone of peru

A methodology of optimizing expenditures for rural road maintenance and rehabilitation is presented. The optimum schedule for pavement overlay and rehabilitation is determined, resulting in minimal costs during the road's economic horizon. In developing countries, the economic horizon usually varies between 10 and 20 years; in Ecuador, it was established at 17 years. During this period most of the road's socioeconomic benefits are obtained. The economic residual value is small relative to other transportation expenditures. Total expenditures during the service lifetime include construction, maintenance, pavement overlay or rehabilitation, and vehicle‐operating costs. The methodology was used in the evaluation of 2,700 km of rural roads in the Ecuadoran province of Chimborazo. The analysis shows that total expenditures will be the least when adequate, timely maintenance is implemented. Due to budget and other administrative limitations, maintenance cannot always be carried out as needed. In such cases, a p...

Optimizing Rural Road Conservation Expenditures

The profile and clearance heights at seven bridges of the New Jersey approach roads to the George Washington Bridge needed upgrading. To do this, nondestructive test (NDT) techniques were carried out on the pavement surfaces to determine the subgrade properties under the existing pavement. The NDT dynamic load and the measured deflection basin were analyzed to calculate the subgrade parameters, the elastic modulus (E) the CBR, and the modulus of reaction (K). The testing and calculation of 100 points, under heavy traffic volume, were completed in four hours. The subgrade parameters were used to design the reconstructed new pavement structure for local environmental conditions and for 20‐yr projected traffic loading.

Jacob Greenstein

Papers

Practical applications of models for pavement maintenance management

Optimizing Rural Road Conservation Expenditures

Use of NDT and Pocket Computers in Pavement Evaluation