1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. SABS 0120 a Part 5 Section MF-1981 Base PART 5 : CONTRACT ADMINlSTRATION SECTION MF CONTENTS Clause Page Number START OF CONSTRUCTION . l General . 1 IMM
4、EDIATELY AFTER THE HANDING OVER OF THE SITE I Sources of Material Supply I . DURING CONSTRUCTION I . Methods of Construction I Non-plastic gravel I Maximum size I Addition of binder I Compaction against kerbs I Single size crushed stone base (waterbound macadam base) I Administration I Target gradin
5、g I . Problems with aggregates and gravel I Aggregate pH 2 Aggregate PI 2 Protection and maintenance 2 QUALITY CONTROL AND OTHER CONSIDERATIONS . ; 2 SABS 0120 8 Part 5 Section MF-1981 Base SABS 1200 MF : BASE NOTE: The clause number(s) given at the beginning or after the heading of a clause is/are,
6、 unless otherwise stated, the number(s) of the relevant clause(s) of SABS 1200 MF. START OF CONSTRUCTION GENERAL. For the purposes of this part of the code contract administration starts with instructions to the contractor to commence work as set out in Subclause 4.1 of Section 0. SOURCES OF MATERIA
7、L SUPPLY. The recommendations given in Subclause 2.1 of Section ME are applicable to this sect ion. DURING CONSTRUCTION METHODS OF CONSTRUCTION Non-Plastic Gravel (Subclause 5.4.4). Coarse gravel containing non-plastic or slightly plastic soil fines and used.in the construction of a gravel base will
8、 usually require slushing and rolling in addition to the compaction specified to enable a firm. well-knit surface to be obtained. In such a case. after being processed and compacted as specified in Subclause 5.4.4 of SABS 1200 MF. the base should be well watered over short sections at a time and slu
9、shed and rolled with compactors andlor heavy flat wheel rollers of mass at least 12 t. Watering and rolling should continue over a section until all excess fines have been brought to the surface of the layer. Such excess fines should be uniformly distributed over the surface of the layer by means of
10、 stiff brooms, and watering, rolling. and brooming should continue until all areas deficient in fines have been suitably corrected. Finally. all excess fines should be removed Erom the surface of the layer. Maximum Size (Subclauses 3.3.l(a) and 3.3.2(a). In order to ensure optimum workability of the
11、 material, the maximum size of. stones should, if possible, not exceed one-third of the thickness of the layer. Addition of Binder_ (Subclause 5.4.2(c). Where a binder material is to be added to the base material, between 30 X and 50%. as directed, of the required amount of gravel should be dumped o
12、nto the road and spread over its full width. The binder material should then be dumped on top of the gravel, spread, and intimately mixed with the gravel until a uniform mixture is obtained. The remainder of the gravel should then be brought onto the road and mixed with the material containing the b
13、inder until a uniEom mixture is obtained. Water should not be added until the binder is fully mixed with the gravel. Compaction Against Kerbs. The contractor should pay special attention to the placing and compaction of base material against kerbs and channels to ensure that the kerb or channel is n
14、ot damaged by the rollers or compactors and that the required compaction is achieved right up to the edge of the kerb or channel. Single Size Crushed Stone Base (Waterbound Macadam Base). The coarse aggregate is first compacted until the density is deemed to be satisfactory (i.e when there is virtua
15、lly no movement or only a slight amount of movement in the layer under a 12 t flat steel wheel roller). While rolling continues the interstices are Eilled. by brooming and watering, with fine aggregate or natural filler conforming to a specified grading. ADMINISTRATION Target Grading (Subclarwe 3.3.
16、l(b). Where the grading of the material available is consistently above or below the average of the applicable grading limits given in Table 1 of SABS 1200 MF. the Engineer may fix a target grading to suit the average grading of the material available provided that the target grading is within the g
17、rading limits given in Table 1 of SABS 1200 MF. The target grading should follow a smooth curve without any marked gaps or excessive quantities of a particular size and should preferably not be near the f iner limits of the grading envelope. The material should then be required to conform to the tar
18、get grading within the following tolerances: Nominal aperture size of sieve. mm 26.5 19.0 9.5 to 1.18 0.30 0,075 Tolerances on target grading, % passing by mass Problems with Aggregates and :ravel. Where the contractor has been allowed to select the source of the base material, it would be reasonabl
19、e to assume that his tendered price covers the cost of dealing with the problems outlined in 3.1.1 and 3.2.3. Under all other circumstances he would be entitled to claim extra payment (unless the project specification had given him adequate warning), but should obtain the engineers authority before
20、proceeding on the lines set out in 3.1.1 and 3.2.3. May 1981 Approved by the COUNCIL OF THE SOmH AFRICAN BUREAU OF STANDARDS SABS 01 20 : Part 5 Section MF-1981 Base 3.2.3 Aggregate pH (Subclause 3.3.2(b). Crusher run having a pH of less than 6 (material that is yellow in colour is particularly susp
21、ect in this regard) should be checked for soluble sulphate content prior to delivery. Hydrated lime may be added under controlled conditions, preferably during crushing and screening, to bring the pH to not less than 10,O immediately after treatment. In certain cases and only with the prior consent
22、of the engineer, neutralizing additives m.ny be incorporated during construction of the base. Aggre ate PI (Subclause 3.3. (c). Fines, if required for correcting areas deficient in fines, should -proved by the engineer before use and should all pass a 4,75 mm screen. The PI of the fraction passing t
23、hrough this screen should not exceed 4 and the material should be free of shales, micaceous and organic materials, and other deleterious matter. Where the PI of available fine aggregate exceeds 6 the PI may be reduced by the admixture f not less than 3 X by mass of hydrated lime to achieve a residua
24、l PI of not more than 4 before the fine aggregate is added to the mixture. Protection and Maintenance (Subclause 5.8). The engineer should appreciate that he accepts responsi- bility for, and will pay for, any damage that is done to the surface, if he authorizes the use of an unprimed base by vehicular traffic. QUALITY CONTROL AND OTHER CONSIDERATIONS The relevant recommendations of SABS 0157) should be applied to the construction of a base.
