*Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*



*Life data measurement of failed road sections.*


### *Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*


**Table 4.** *Alternate visit comparison showing deterioration rate.*

*Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*


**Table 5.**

*Road deterioration status change.*

There is a steeper increase after 225 days in the hazard function in **Figure 15**. This shows that the tendency of the depth of the road to deteriorate increases after the 225th day. This is due to the value of *<sup>β</sup>*^ <sup>¼</sup> <sup>22</sup>*:*50 being far from 1, and the approximately 95% confidence interval for *<sup>β</sup>*^½ � <sup>10</sup>*:*02, 50*:*<sup>53</sup> does not contain 1. The plot of the reliability test that shows the trend of reliability (the probability of the depth of the road not deteriorating at time t) with time is given in **Figure 16**. The deterioration started after the 225th day. There was a sharp rate of deterioration (decrease in the reliability status) of the depth of the roads Lucky Way, Mission Road, New Benin


#### **Table 6.**

*The shape parameter β and the 95% confidence interval of β.*

**Figure 13.** *The failure rate or hazard function plot for the width of the roads.*

#### **Figure 14.**

*The reliability test plot for the width of the roads.*


#### **Table 7.**

*The shape parameter β and the 95% confidence interval of β.*

Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road after the 225th day.

Weibull Reliability Test for the Deterioration of the Length of the Roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road.

*Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*

**Figure 15.** *The failure rate or hazard function plot for the depth of the roads.*

**Figure 16.** *The reliability test plot for the depth of the roads.*


#### **Table 8.**

*The shape parameter β and the 95% confidence interval of β.*

The shape parameter *β* and the 95% confidence interval of *β* for the data on length of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road are given in **Table 8**. The road is reliable and there is not enough evidence for the deterioration of the road if the shape parameter *β* is close to 1 and the 95% confidence interval of *β* contains 1.

There is sufficient evidence for the deterioration of the length of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road since the value of ^*<sup>β</sup>* <sup>¼</sup> <sup>6</sup>*:*71 from **Table 8** is far from 1, and the approximately 95% confidence interval for *<sup>β</sup>*^½ � <sup>2</sup>*:*50, 17*:*<sup>99</sup> does not contain 1. The plot of the failure rate or hazard function, which describes the likelihood of deterioration in length during the next time increment is given in **Figure 17**.

**Figure 17.** *The failure rate or hazard function plot for the length of the roads.*

**Figure 18.** *The reliability test plot for the length of the roads.*

There is a steeper increase after 140 days in the hazard function in **Figure 17**. This shows that the tendency of the length of the road to deteriorate increases after the 140th day. This is due to the value of *<sup>β</sup>*^ <sup>¼</sup> <sup>6</sup>*:*71 being far from 1, and the approximately 95% confidence interval for *<sup>β</sup>*^½ � <sup>2</sup>*:*50, 17*:*<sup>99</sup> does not contain 1. The plot of the reliability test that shows the trend of reliability (the probability of the length of the road not deteriorating at time t) with time is given in **Figure 18**. The deterioration started after the 100th day. The rate of deterioration was minimal between the 100th to 150thday; after the 150thday, there was a sharp decline in the reliability status (increase in the deterioration rate) of the length of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road.

#### **7. Conclusion**

In this study, eight (8) roads from Nineteen (19) mapped failing roads by means of purposive sampling the Benin city area of Edo state in Nigeria were assessed. Data collection follows five different routes in five (5) different field visitations at intervals of three (3) months for each visit. During visits variational failure growth in terms of

*Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*

length, width and depth was obtained by tape rule measurements, rolling measuring rule, pegs, paints and photographs. Data collected were scrutinized and subjected to Weibull analysis to obtain road failure-specific sequences in reliability terms to validate and underscore quality impairments in constructed road pavements. Quality impairments originating from road component materials failure were evident in roads failing as early as six (6) months after construction. Progressive failure was noticed to be aided by further deterioration owing to lack of maintenance according to the types of road failures photographed in this paper. This is further augmented by relation to monotonicity failure theory elucidated in Gupta [26] with steady state progressive deterioration shown in the bathtub log-convexity property of the Weibull measurement count. A validation of quality impairment was deduced from a degenerating reliability Weibull analysis as corroborated in the literature of Efimenko and Moisejenko [2] and Bazhanov [5]. By undermining quality control process at construction, steep failures from a deteriorating pavement aided by the stress/strain mortal force of decrement prevailed early enough in the lifetime of the pavement to cause road failure.
