The paper deals with the behavior of fluid cement pastes, formulated from Self Consolidating Concretes (SCCs), and the experimental correlation of fundamental rheological properties, such as the yield stress and the viscosity, with measurements from field tests, such as the mini-cone slump flow test. As a matter of fact, several...
The gradual evolution of the material properties of a cement-based material, i.e. the stiffness of cement paste, is the result of the continuous change of the microstructure with the progress of the hydration process. Based on an existing micromechanical model for the simulation of the shear and elastic modulus of...
In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection
method and the microstructure in cement-based material is investigated. Three cement pastes
(Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25
°C were examined. The ultrasonic shear wave reflection...
Cracking is one of the most common concerns cited by owners of structures adjacent to construction or mining blasting. While a large database of case studies documenting the relative insignificance of ground motion induced by responsible blasting compared to weather effects on cracks in nearby structures has been established, the...
Most studies of crack response have focused on opening and closing of a crack in the plane of the wall in which the crack occurs. Crack movement also occurs perpendicular or normal to the plane of the wall. This paper will examine and compare the in-plane and out-of-plane (normal) response...
Surveillance of large geotechnical projects requires autonomous collection of data from a wide range of instrument types. An equally large range of data formats are employed by these measurement systems. A data exchange protocol is needed to make field data available for interpretation on a variety of platforms. This paper...
Blasting and climatological response of cracks are compared for structures constructed of concrete block typical of home construction in Europe. While much has been written comparing micrometer crack response of wood frame structures typical of residential construction in North America, little has been written concerning response of structures more typical...
This is the text of a public address at the Nigerian Institute of International Affairs delivered soon after the inauguration of Nigeria’s Fourth Republic. It identified several priorities after fifteen and a half years of military government. The country’s eroded legislative, judicial, and other state institutions needed to be rebuilt...
This opinion piece, written by two long-term students of Nigerian politics, proposed a different course to the one taken following the death in mid-1998 of a military tyrant and the elected president he had imprisoned. It called for the creation of a caretaker national government of respected civilians that would...
This revised version of a paper presented at a conference at M.I.T. on State, Conflict, and Democracy in 1997 pulled together key dimensions of a Nigeria that had drifted far from constitutional and democratic governance. State and society had become increasingly criminalized; the educational system and other social sectors were...
More than taking Nigeria back into the “dismal tunnel” of military rule, after seizing power in November 1993, Sani Abacha raced through the playbook he knew as a senior member of Babangida’s junta. Like Babangida, he pushed back the announced date for the return to civilian rule, launched an exercise...
When this testimony was given, there was still hope that Ibrahim Babangida would transfer the presidency to the elected Moshood Abiola before he left office on August 27, 1993. In that way, Nigeria would join the wave of post-Cold War democratizing nations. I had earlier called for a “transition in...
A long-running wager took place between the Babangida regime (1985-1993) and Nigerian civic, professional and political groups that the former would honor its commitment to usher in a Third Republic via free and fair elections. The June 12, 1993 elections were as free, fair and competently administered as could be...
This paper was written at the midway point in the governing of Nigeria by a paradoxical individual, Ibrahim Babangida. It should provoke further studies of his 8-year rule, 1985-1993, that seemed transformative during much of this period but ended in disarray and disappointment. The ideological orientation of the Nigerian economy;...
In this article, a Nigerian military system of governance is explicated. It was the dominant mode of governance in Nigeria until civilian rule was restored in 1999, initially under a former military ruler. Starting from the first military coup in January 1966, Nigeria experienced over 33 years of this system,...
As many systems of military and autocratic rule came under challenge in Africa, Nigeria lost its leadership position in a democratizing era with the collapse of the Second Republic, 1979-1983. Four military heads-of-state followed. One of the most hopeful transitional experiments in Africa, conducted under General Ibrahim Babangida, 1985-1993, ended...
In this essay, key features of Nigerian governance since independence are reviewed. The military had ruled the county for thirteen years and civilian politicians, in two phases, had done so for ten. Military governments involved significant participation by civilians, so there was overlap between these successive systems. Moreover, the military...
The forcible ending of Nigeria’s second attempt at constitutional civilian rule since independence in 1960 is a mixed story. The 1983 general elections were tarnished by violence and fraud. They took place in a context of economic decline and policy disarray. However, the opposition still retained an important share of...
This article resumes the exploration of Nigeria’s political economy and the entrenchment of a prebendal mode of attitudes and behaviors. It takes up the shift to a mono-mineral export economy, the socio- economic proclivities of the dominant class, the considerable expansion in the state’s economic role, and the distinct pattern...