Stabilising Road Pavement Safe Work Method Statement

For skin exposure, immediately remove contaminated clothing and rinse affected area with large quantities of clean water for minimum 20 minutes. Do not scrub or use soap initially as this can drive alkaline material deeper into skin—gentle flushing is most effective. After thorough rinsing, wash with mild soap and continue rinsing. Seek medical assessment for any exposure causing redness, pain, or skin damage. For eye exposure, immediately flush with clean water or eye irrigation solution for minimum 20 minutes, holding eyelids open to ensure thorough flushing of all surfaces. Remove contact lenses if present after initial flushing. Seek immediate emergency medical treatment—eye exposure can cause permanent damage including blindness. All cement and lime exposures should receive medical assessment even if symptoms seem minor initially. Chemical burns from alkaline materials develop progressively over hours and early intervention prevents serious injury. Never apply ointments, creams, or neutralising agents without medical direction.

Adequate dust suppression is achieved when visible dust generation is minimal and dust does not extend beyond the immediate work zone. Visual assessment is primary monitoring method—if dust clouds are visible beyond 10-20 metres from operation point or persist after material is wetted, dust suppression is inadequate. Workers downwind of operations should not be experiencing dust exposure affecting breathing or visibility. Increased water application rates during spreading and pulverising operations usually resolves dust issues. However, avoid over-wetting which causes material to become muddy and affects compaction—moisture content must remain within specification range. Wind speed significantly affects dust generation—if dust cannot be controlled despite maximum water application, suspend operations until wind speeds decrease below 30km/h. Some specifications require air quality monitoring using particulate meters measuring dust concentrations at work zone boundaries. If monitoring shows PM10 particulate levels exceeding 50 micrograms per cubic metre (or other specified limits), implement additional dust controls or cease operations. Remember that dust control is both worker safety issue and environmental compliance requirement—complaints from nearby residents indicate inadequate dust suppression.

Water cart operators should maintain minimum 5-metre distance when making initial water application to freshly spread lime. This separation allows the exothermic reaction to commence without exposing operator to generated steam and heat. The reaction between quicklime (calcium oxide) and water produces temperatures exceeding 150°C and generates large volumes of steam creating scalding hazard. Even hydrated lime produces significant heat though less extreme than quicklime. After initial reaction subsides (typically 1-2 minutes), distance can be reduced for subsequent water passes achieving final moisture content. Apply water in multiple light passes rather than heavy single application—this distributes reaction heat over time reducing intensity. Ground workers should remain outside 10-metre radius from active lime wetting operations. The exothermic reaction creates additional heat stress for workers—schedule lime stabilisation during cooler parts of day where possible. Brief all personnel on lime reaction hazards before commencing operations. Some workers may be unfamiliar with lime properties and approach wetted areas without understanding heat generation risks. Emergency response equipment including burn dressings should be immediately available during lime stabilisation work.

Generally, pavement stabilisation should not proceed during rain or when rain is forecast within the curing period (typically 24-72 hours depending on stabilising agent). Rainfall during spreading operations washes away dry stabilising agent before mixing occurs, wasting material and preventing proper treatment. Rain during or immediately after mixing dilutes the stabilising agent reducing effectiveness and potentially causing complete failure of stabilisation. Rainfall on freshly compacted stabilised pavement before adequate strength development causes raveling, erosion, and loss of compaction. Some specifications explicitly prohibit stabilisation work when rain is forecast within 24 hours or when existing pavement is wet. Exceptions exist for bitumen emulsion stabilisation which is less affected by moisture, though excessive water still creates problems. If unexpected rain occurs during operations, immediately apply temporary surface protection using plastic sheeting or rapid-setting sealing products if available. Bitumen emulsion prime coat can provide rain protection if applied immediately after compaction. If rain damages freshly stabilised pavement before adequate curing, affected areas may require removal and re-stabilisation. Prevention is always preferable—monitor weather forecasts closely and avoid commencing stabilisation when rain is likely within curing period.

P2 particulate respirators are minimum requirement for workers exposed to cement, lime, or silica dust during spreading, pulverising, and compaction operations. These half-face respirators filter 94% of airborne particles providing protection against respirable crystalline silica, cement dust, and lime dust. P2 respirators must be properly fitted—facial hair prevents adequate seal reducing protection. Annual fit testing is mandatory for all workers wearing tight-fitting respirators ensuring proper seal is achieved. For extended duration work (more than 4 hours continuous) or high-dust environments, upgrade to powered air-purifying respirators (PAPRs) providing higher protection level and reduced breathing resistance. PAPRs use battery-powered fans drawing air through filters delivering clean air to full facepiece or hood. They provide protection even with facial hair and reduce heat stress compared to tight-fitting respirators. All respiratory protection must comply with AS/NZS 1716:2012 standard. Respirators require maintenance including filter replacement, cleaning, and inspection before each use. Workers must be medically cleared to wear respirators—some medical conditions preclude respirator use. Inadequate respiratory protection during stabilisation work causes chronic lung diseases including silicosis which is irreversible and progressive. These conditions develop over years of cumulative exposure making prevention essential.

Curing duration depends on stabilising agent type and strength requirements. Cement-stabilised pavement typically requires minimum 7 days curing before opening to traffic, with some specifications requiring 14 or 28 days for full strength development. Light construction traffic may be permitted after 3-5 days if adequate early strength is achieved. Lime-stabilised pavement often allows earlier trafficking—typically 3-7 days depending on lime content and site conditions. Bitumen emulsion stabilisation may allow trafficking within 24-48 hours after adequate curing. During curing period, maintain traffic management protecting stabilised pavement from public traffic. Barriers, signage, and traffic controllers prevent unauthorised access. If pavement must remain open to traffic during curing, implement speed restrictions and axle load limits preventing damage to developing pavement. Apply surface sealing immediately after compaction preventing moisture loss—cement requires moisture for hydraulic reaction to progress. Water curing using light spray maintains surface moisture but avoid over-wetting causing saturation. Monitor cured pavement for raveling, cracking, or damage particularly after rain events. Some projects specify strength testing before trafficking is permitted—core samples or deflection testing verify adequate strength development. Never allow full traffic loading on stabilised pavement before specified curing period completes—premature trafficking causes permanent damage requiring costly repairs.