SYMBOLS
a calorimeter calibration constant
[J/K/h]
A cross-sectional area [mm2] Ac air content [%]
Ap area of the tracing paper sheet
[mm2]
Apf wet area [mm2]
b calorimeter calibration constant
[J/K2/h]
b Van Genuchten parameter [-] c set-up thermal capacity [J/K] ca aggregates thermal capacity
[J/kg/K]
cc cement thermal capacity [J/kg/K] cCc container thermal capacity [J/kg/K]
cw water thermal capacity [J/kg/K] Cacc CO2 concentration in accelerated
conditions [%]
Cb basic creep [μm/mm] Cnat CO2 concentration in natural
conditions [%]
Ctot total creep at a certain age
[μm/mm]
d minimum aggregate size [mm]
d1, d2 lateral dimensions [mm]
dap average depth of water
penetration [mm]
di intruded pore diameter [nm]
ds interplanar spacing [nm]
D diameter [mm]
D maximum aggregate size [mm] D/d aggregate size ratio [-]
Dnssm non-steady-state migration
coefficient [10-12 m²/s] E energy [eV]
XI
Ea activation energy [J/mol] EDF expected durability factor [-]
Es secant modulus of elasticity [MPa] fc compressive strength [MPa] fck characteristic compressive strength
[MPa]
fcm average compressive strength
[MPa]
fcst splitting tensile strength [MPa] fct flexural strength [MPa]
fct direct tensile strength [MPa]
F maximum load [N]
F(x) cumulative particle distribution
function (Weibull or Log-logistic) [%]
gi p-wave acceleration [m/s2] G gauge length [mm]
h height of the specimen [m] I intensity crossing the circuit [A] Ir span [mm]
k Spectral series constant [eV] K constant [m/s]
K measure of particle size spread [-] Kapp apparent gas permeability
coefficient [m2]
Kb positive integer as a function of
the type of binder and aggregates [-]
Kc capillary water absorption
coefficient [kg/m2·√s]
KCO2 carbonation rate at certain CO2 concentration [mm/√years]
Kcorr,CO2 corrected carbonation rate at
certain CO2 concentration [mm/√years]
Kr relative gas permeability
coefficient [-]
Ks specific strength ratio [-] L length of the specimen [mm] L0 length comparator reading of the
reference bar [μm]
Li length comparator reading of the
specimen at certain age [μm]
Lm average chord length [mm] Ls spacing factor [µm]
ma mass of the aggregates [kg]
mc mass of the cement [kg] mCc mass of the container [kg]
mw mass of the water [kg]
MD median diameter of intruded pores
larger than 4.50 nm [µm]
Mdry mass of the oven dry sample [g] Mp mass of the tracing paper sheet [g] Mpf mass of the wet area reproduction
in the tracing paper [g]
Mpyk mass of the pyknometer full of
water [g]
Mrd mass of the oven dried aggregates
[g]
Msat mass of saturated aggregates
inside the pyknometer [g]
Msat mass of the vacuum saturated
sample weighed in air [g]
Mssd mass of the saturated aggregates
with dry surface [g]
Mx mass of the sample at certain age
[g]
nr order of reflection
N total number of air void chord
lengths [-]
p paste content [%] P pressure [N/nm2 or Pa] Patm atmospheric pressure [Pa]
Ps strength contribution in
percentage [%]
PV total intruded pore volume down
to a diameter of 4.50 nm [ml/g]
q heat production [J/g/h]
qnat percentage of natural aggregates
[%]
Q cumulative heat production [J/g] Q0 mass prior to the test [kg] Qg gas flow rate [m3/s]
Qn mass at saturation point [kg] R universal gas constant [J/mol/K] Ra asphalt [%]
Ra surface roughness [mm] Rb ceramic particles [%] Rc concrete and mortar [%] Rg glass [%]
XII
Rn contribution to strength of the
natural aggregates [MPa]
Rr contribution to strength of the
recycled aggregates [-]
Rs electrical resistance of the sponges
[Ω]
Ru unbound natural aggregates [%] Sa autogenous shrinkage before the
loading [μm/mm]
SD saturation degree of the sample
[%]
SL sampling length [mm]
St total shrinkage before the loading
[μm/mm]
Sx shrinkage at certain age [μm/mm] t exposure period [s, h, year] te equivalent age [h]
T temperature [°C]
Ta total chord length of air voids
[mm]
Tc temperature under semi-adiabatic
conditions [K]
Tp total chord length of paste [mm] Tr temperature of reference [K] Ttot total surface distance traversed
[mm]
U applied voltage [V] v p-wave velocity [m/s]
vi asymptotic p-wave velocity [m/s] V potential difference between
electrodes [V]
w/c water/cement ratio [%], WA24 24 hours water absorption [%]
Wd weight of the dried specimen
weighed in air [g]
Ws weight of the saturated specimen
[g]
Ww weight of the saturated specimen
measured under water [g]
x percentage of particles passing a
specific sieve [%]
xd average penetration depth [mm] X1 gypsum [%]
X2 other impurities [%]
y(x) profile height function [mm] Z atomic number [-] α heat loss [J/K/h] αs specific surface [mm-1] δ standard deviation [-] ∆T temperature rise [K] ∆t time interval [h]
εa average strain on the last loading[-
]
εc strain caused at a certain load [‰] εc1 peak strain [‰].
εe effective porosity [-] εp average strain on the last
unloading [-]
εs strain in the sealed specimen
under load at a certain age [μm/mm]
εu strain in the unsealed specimen
under load at a certain age [μm/mm]
γ mercury surface tension of [N/nm] η dynamic viscosity [Pa·s]
T open porosity after drying at a
certain temperature [%]
λ mean particle size [mm] λx X-ray wavelength [nm]
µ empty calorimeter thermal
capacity [J/kg/K]
θ angle of X-ray incidence [º] θi mercury intrusion angle [º]
ρ density [kg/m3]
ρa apparent specific gravity [Mg/m3] ρc electrical resistivity [Ωm]
ρrd dry bulk specific gravity [Mg/m3] ρssd saturated with surface dried bulk
specific gravity [Mg/m3]
ρw density of water [kg/m3] σ shielding constant [-] σ/E elastic strain [-]
σa stress corresponding to one third
of the compressive strength [MPa]
σc/fcm relative stress [-]
σp stress corresponding to the
1
1. PROBLEM STATEMENT
Although human activities have always had an impact on the environment, after the industrial revolution, the technological development achieved has not only meant that humankind has a greater capacity for economic growth but also a greater negative impact on the environment. In the last 50 years, a growing social concern about the protection and conservation of the environment has developed among worldwide society. Generally, the book “Silent spring” by Rachel Carson (1962) is considered as the catalyst of the awakening of the environmental awareness in the general public. In any case, the 1970s was a crucial time period in the development of the environmental conscience. Firstly, the creation of the Club of Rome and the subsequent publication of their environmental concerns on the limited nature of the natural resources in the so-called Meadows Report (Meadows et al., 1972) played an important role highlighting the interdependences between environment and economy despite all the criticism received regarding the adopted assumptions and methodologies. And later that same year, the celebration of the United Nations Conference on the Human Environment was the first sign of worldwide recognition that the protection and improvement of the environment is a major issue affecting the human well-being and the economic development.