EX P LANATl(il\l CY TEIII.IS
Exposure Conditions
Mild conditions.
a i r .
Mndcrate conditions. Conditions under which the concrete is
a) sheltered from severe rain and is not subject to freezing when w e t ; or
b) buried i n non-aggressive soil.; or
c) continuously under fresh water.
Severe condition?..
a) Driviny rain;
b) a l t e r n a t e wetting and drying o u t ;
c) freezing when w e t ;
d) fresh water ( a t the water-line);
c) splashing or s p r a y i y with fresh water;
f ) corrosive fumes or heavy condensation of water;
g) aggressive soil;
h ) s a l t - l a d e n a i r .
very severe c o n d i t i o n s .
a) Sea-water (below or at the water-line);
b) sea-wat.er spray or windborne s a l t s ;
c) water containing sulphates or chlorides;
d ) highly corrosive fumes.
Strength Concrete. A s t r e n g t h concrete is designated by its spec:ified s t r e n g t h followed by the s i z e of
stone used in its manufacture, e.g. 30 MPa/l9 mm r e f e r s to a Grade 30 mix made with 19 mm stone.
Joints. The location of j o i n t s is controlled by design requirements and construction l i m i t a t i o n s . All
j o i n t s are "construction j o i n t s " within the general meaning of the term. Joi.nts shown on the drawings or
i n the schedule are "designated j o i n t s " . The Engineer may, i n collaboration with the Contractor, approve
f u r t h e r j o i n t s before the casting of concrete, which j o i n t s w i l l then become "designated j o i n t s " .
terms "constructional j o i n t s " , "movement j o i n t s " , "contraction j o i n t s " , and "expansion j o i n t s " are used
to i d e n t i f y various types of designated j o i n t s .
formed during concreting when plant f a i l u r e , inclement weather, or some other unforeseen event has
enforced a h a l t i n the placing of concrete and has thus created E! s i t u a t i o n i n which a construction j o i n t
hds to be made i n a location t h a t was n e i t h e r designated nor approved before the commencement of
concreting.
MATERIALS
APPHGVAL OF MATERIALS. The Contractor s h a l l supply i n good t i m e to the Engineer, for his approval,
samples of the aggregates (and, i f so ordered, of the water) that. he proposes to use f o r the concrete and
s h a l l furnish evidence t h a t the water and aggregates comply w i t h the requirements of 3 . 3 and 3.4.
Evidence s h a l l be i n the form of e i t h e r
a) a statement frol;, an approved laboratory of the r e s u l t s of tests, or
b) an a u t h o r i t a t i v e report or record of previous experience.
CENKNT
Applicable Specifications.
milled granulated blastfurnace slag (see SABS 626) s h a l l comply with the relevant requirements of the
following s p e c i f i c a t i o n s :
BS 1370 Low h e a t Portland cement
SABS 471 Portland cement (ordinary, rapid-hardening, and s t J p h a t e - r e s i s t i n g )
SABS 626 Portland blastfurnace cement
SABS 031
Alternative l'ypcxs of Cement.
when s p e c i f i c a l l y authorized by the Engineer. (See 8.1.3.2 and E.1.3.3.)
Sllorage of Cement. Separate storage f a c i l i t i e s s h a l l be provideC, on the S i t e f o r each type of cement
used.
Cemant t h a t is stored on the S i t e s h a l l be kept under cover t h a t provides proper protection a g a i n s t
moisture and other f a c t o r s t h a t may promote d e t e r i o r a t i o n .
Storage of cement i n bulk i n weather-proof silos or s i m i l a r c o n t a i n e r s w i l l be permitted provided t h a t
the cement drawn f o r use is measured by mass and not by volume.
WATER. Water s h a l l be clean and f r e e from injurious amounts of acids, a l k a l i s , organic matter, and other
substances t h a t may impair t h e strength or d u r a b i l i t y of concrete.
AGCR)LGATES
Applicable Specification. Both the coarse agsregate (stone) and the f i n e aggregate (sand) s h a l l comply
with the relevant requirements of SABS 1083.
use of Plums. Where plums are required to be used, or are permitted, they s h a l l
a) be h a r d , clean stone of mass 15 t o 55 kg;
b) c o n s t i t u t e not more than 20 % of the volume of the concrete;
c) have no adhering film or coating;
d) be such t h a t no plum has a dimension g r e a t e r than one-third of the smallest dimension of the concrete
member or greater than 300 mm, whichever is less;
e ) each be surrounded by concrete of depth a t least 80 mm; and
f ) have an aggregate crushing value a t least equal to t h a t specified for coarse aggregate i n SAnS 1.083.
Storage of Aggregates. Aggregates of d i f f e r e n t nominal s i z e s s h a l l be s t o r e d separately and i n such a
way t h a t
a) segregation is minimized; and
b) intermixing of d i f f e r e n t materials and contamination by foreiyri matter is prevented.
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